Video Handbook 2015

2015

Video Handbook

version 2.2.0

DVD Video vs DVD-ROM2

2015 Video HandbookMatt Stephens | Production Project Manager | ELT | Cambridge University Press 2

Introduction2

This 2015 handbook has been designed as a thorough update to the 2012 DVD Handbook and also something of an expansion, adding in whole new chapters on file size, video quality and a thorough description of the program Handbrake, which can be used to compress video in order to make it compatible with the various video inclusive produce such as eBooks we create. The handbook will be updated periodically as the business needs require either with new content and chapters or by expanding on existing content. Suggestions and requests for inclusion can be sent to [email protected]

The 2015 handbook

The Quantel Digital Fact Book, which remains the definitive guide in the field of digital video. It’s a free resource and the latest edition is a searchable web-based version.http://digitalfactbook.tv

Alternatively a PDF of the 2008 version can be found here:ELT PC Share/OPERATIONS TEAM/PRODUCTION UNIT/STAFF FOLDERS/Matt/Documents/Video/PDF/Quantel Digital Fact Book.pdf



Introduction 2

Video Basics

Video Standards 5

Aspect Ratios (Introduction) 6

DVD

DVD Video vs DVD-ROM 8

Region Encoding 9

Copy Protection 10

DVD Disc Capacity 11

DVD Authoring (Introduction) 13

DVD Navigation 15

DVD Copyright 17

DVD Menu Creation 18 Size and Working Area 18 Anamorphic Compression 18 Safe Area 19 Fonts 19 Broadcast Safe 20 Buttons and Sub Pics 20 Menu Button Navigation 21

DVD Video Chaptering 23

DVD Testing 24

DVD Final Assets 25

Outputs: Introduction 25 DVD-R 25

Table of Contents3

DDP as a successor to DLT 25DDP Format and Structure 26Outputs in CAMS 26 DDP 26 UDF 26Burning a disc from a DDP 27

Source Files: Introduction 28Source Files in relation to DVD 28High-Definition Source Files 29Delivery of Source Files 30Source Files out of scope 30Source Files in CAMS 31

Subtitles

Subtitles: Introduction 32 Anti Aliasing 33 Timecode 34 Subtitle Formatting 35 Spruce Technologies Subtitle (STL) 36 Header 36 Indivdual Subtitles 37 Subtitles for other product types 39 VTT Subtitles for Presenation Plus 39 Timecode conversion 41 Resources 41

Digtial Video

Digtal Video (Introduction) 42

Video Codecs 44

A new video standard 44 LaserDisc/Analogue 44 VCD/MPEG-1 44 DVD/MPEG-2 45 H.264/MPEG-4 45


Video Compression 46

Frame Rate 46 GOP Pattern 46 Picture Size 47 Data Rate 47

Bitrate Calculating 48 How to estimate video file size 48 Video quality 49 Sample video specifactions 50

Handbrake

Handbrake (Introduction) 51

What is Handbrake? 51 Upgadring to the latest version 51 Handbrake: Main Interface 52 Source 53 From DVD-Video 53 Single file 53 Video 54 Audio 55 Subtitles and Chapters 56 Picture Settings 56 Handbrake Presets 57

The 5 presets 57 Settings for other aspect ratios 58



Video Standards5

There is no one set of video specifications used across the world. For various reasons, different countries have amended and adapted a set of similar but very different standards.

A system called PAL is used in UK, Europe, Africa, South America the East and Australia. An alternative system, NTSC, is used in the USA, Canada and Japan. Finally SECAM is used in France and the remaining territories (though this is now being phased out).

Prior to the introduction of Plasma/LCD/LED televisions, TVs were constructed around a cathode ray tube (CRT) and displayed a picture that was made up from a series of horizontal lines. A PAL signal is comprised of 625 lines, whereas NTSC only contains 525, leading to historic assumptions that NTSC was of a lesser quality (though in reality video quality is determined by a great number of factors, not least of all the quality of the source material, and not so easily labelled in terms of ‘best’ and ‘worst’).

NTSC equipment is traditionally limited by generally not being able to play a PAL or SECAM signal (whereas PAL can, as a rule, play NTSC). Although then, whilst PAL is the dominant video standard in the world in terms of number of televisions/territories that use PAL, ironically it makes more sense to adopt NTSC, as NTSC TV sets will be able to natively play NTSC and PAL TV sets can easily convert an NTSC signal.

An example of this reasoning can be seen with music DVDs which are very often sold in the UK despite being an NTSC picture (often consumers would not even realise).

NTSC PAL or PAL/SECAM SECAM

All DVDs produced by Cambridge University Press should therefore be in the NTSC television standard to ensure maximum global compatibility. It is important to note that this needs to be specified to suppliers at the start of a project as whilst modern video equipment can be easily converted to film in either standard, once video has been shot, converting one video standard to another can be expensive.



Aspect Ratios: Introduction6

Aspect Ratio refers not to the size of a video image, but rather to it’s proportions. At its most basic, it’s an expression of width vs height with both represented as a number separated by a colon. A picture that is completely square would therefore be 1:1 and a picture that is twice as wide as it is tall would be 2:1. Video can be produced in any number of aspect ratios (most commonly seen at the cinema where films come in many different aspect ratios). For our purposes however, we will limit the discussion to two only.

4:3 is the original aspect ratio and as old as the history of cinema itself. 4:3 is something of an incorrect term as the actual proportions are 1.37:1 as officially approved by the Academy of Motion Picture Arts and Sciences (who annually host the Oscar awards) and this ratio is known in the industry as Academy.

This aspect ratio was for many years the standard used on television sets and therefore it is a very common, though now somewhat dated ratio. Archive footage will often be in this ratio.

Driven by the desire of fans to see films as they were shown in the cinema, rather than cropped at the edges to fit a 4:3 television, a change began in the late 1980s.

Videos began to be released in new ‘widescreen’ formats with black bars added to the top and bottom of the picture in order to achieve the desired effect (a process known as letterboxing).

As widescreen became more popular, television manufacturers looked to change the shape of television screens to match this new content. As discussed above, there is no single standard for aspect ratios: 2.4:1, 2.35:1, 1.85:1 and 1.66:1 are all common cinema sizes (the curtains hide this by not opening the same amount for every film).

A compromise was reached by creating a new standard of 16:9 which would accommodate many of the smaller widescreen sizes without problems (though larger sizes would still require black bars at the top and bottom of the screen.

All video produced for Cambridge University Press should be shot/rendered at 16:9 ratio as standard.


1.85:1 FlatLetterbox

1.33:1Academy Standard 4.3 16:9 Widescreen

Letterbox

2.35:1 ScopeLetterbox

4.3 Aspect ratios

1.33:1 is the standard that was used in early feature �lms and was the standard in television throughout the 20th century.

16:9 Letterbox presents a 16:9picture in the 4:3 frame by

using black bars to mask the topand bottom of the picture.

1.85:1 Flat is the standard aspect ratio for many feature�lms. Again, this is masked to

�t the 4.3 frame.

2:35:1 Cinemascope is the wider cinema format for many feature

�lms. Again, this is masked to�t the 4.3 frame.

As the image is smaller than thewidescreen frame, black bars need to be added to the edge to ‘pillarbox’ the image. As the image is not resized, no

quality loss should occur.

16:9 WidescreenPillarbox

1.85:1 Flat 2.35:1 Scope

16:9 Widescreen 1.85:1 FlatWidescreen

2.35:1 ScopeWidescreen

As the image was already set to the correct aspect ratio removing the barsand zooming the picture will �t a 16:9frame. As the image is zoomed, some

quality loss will occur

As the image was already set to a wide aspect ratio the amount it needsto be zoomed is reduced. As the image was wider than 16:9 some black bars atthe top and bottom will be necessary.As the image is zoomed, some quality loss will occur

DVD only supports a 4:3 aspect ratio, however, by compressing a 16:9 image horizontally, the entire image can �t into the necessary shape. The DVD player then expands out this image to �t a 16:9 television. The advantage of this process is to allow the entirety of the 4:3 frame to be used with the minimum of black bar letterboxing. video presented in this manner is said to be “anamorphically enhanced”,or “enhanced for 16:9”.

16:9 AnamorphicWidescreen

16:9 Widescreen

16:9 Widescreen 1.85:1 FlatWidescreen

2.35:1 ScopeWidescreen

No conversion necessary As the image was already set to a wide aspect ratio the amount it needsto be resized is reduced. As the image was wider than 16:9 some black bars atthe top and bottom will be necessary.As the image is shrunk, no quality loss should occur

Widescreen Aspect ratios

DVD video has a 4:3 picture aspect ratio, the same proportions as pre-widescreen televisions. One way of creating an image that is wider would be to add black bars to the top and bottom of the frame. However would mean that the video is not making full use of the frame (the black bars are essentially dead space). A more effective way to achieve a 16:9 ratio is to anamorphically enhance the image. Simply put, the image is squashed horizontally, making it appear quite tall and thin. This allows an image to be stored that is wider than the frame it’s set in. During playback by a DVD player the image is then stretched back out to the 16:9 widescreen format, restoring the image to its correct proportions and removing the distortion. None of this process will be visible to the end user.

All DVDs shall use a widescreen picture that has been enhanced for widescreen televisions. As the source footage may have been created in a number of different aspect ratios, the chart below demonstrates how these will translate into one single picture size.




DVD, or Digital Versatile Disc, is a type of optical media measuring 12cm across, the surface of which is marked with millions of pits that are read by a laser, just as a needle reads a groove on a vinyl record. In this regard, it performs and functions (and looks) like a compact disc. Where DVD varies is in capacity - a standard DVD can hold roughly six times more information - and in the applications for which it can be used. For the purposes of this document, we will deal specifically with DVD Video, which is a disc that contains specifically formatted video files that can be read by a set-top DVD player and viewed on a television.

This is a key distinction as other types of disc may work in a computer only and not function in a set-top DVD player. These discs are know as DVD-ROMs and may contain any manner of files including video, though if the video has not been correctly encoded and authored, it will not be compatible with a set-top player.

The distinction between the two types of disc is expressed with the two different symbols that will need to be placed on the on-body label and also any related packaging:

The DVD video logo should be used on every disc that can be played in a set-top DVD player regardless of whatever other content may feature on the disc. The symbol acts to inform the customer that this is a video disc.

WILL play on a set-top DVD player.WILL play in a computer DVD drive.WON’T play in an Audio CD player.MIGHT contain files a computer can read.WILL contain video and audio.

The DVD-ROM logo should be used on discs that are designed to play in computers ONLY. The symbol should therefore be used to specify that the disc would not play in a set-top player, even if it in fact contains video files.

MIGHT play on a set-top DVD player.WILL play in a computer DVD drive.WON’T play in an Audio CD player.WILL contain files a computer can read.MIGHT contain video and audio.

If a disc is a DVD Video and also contains ROM content, it is acceptable to use both symbols to emphasize this fact and highlight a potential sales feature, however the disc must always be referred to in the first instance as a DVD Video and not a DVD ROM.

It is important to follow these conventions correctly in order to both be understood by your DVD supplier and also in order to correctly identify your disc to the customer.



Region Encoding9

This feature was introduced at the request of the film studios, so that they could limit which discs could be sold and played in different parts of the world. The map was broken into 6 distinct regions (territories) as illustrated below (an additional two regions, 7 and 8, are reserved for pre-releases and international venues such as cruise ships). This process of territories can be seen as largely redundant, as many DVD players are designated and sold as region free, that is to say they will play discs from all 6 regions. Unless the content of one of our discs was subject to a licensing agreement that explicitly forbade us from selling in other countries, we should request that our discs be set without region encoding as standard.

DVD Regions 1 2 3 4 5 6

A similar system has been incorporated into Blu-Ray discs. The regions have now been simplified down to only three territories, A, B and C. As with DVD, we should create Blu-Ray discs without region encoding.

Blu Ray Regions A B C



Copy Protection10

DVD has two forms of copy protection that are available. The first is Content Scrambling System, or CSS. The purpose of this type of protection is to prevent a user from copying the contents of a DVD to their computer hard drive, the first step necessary in order to copy a disc. Attempting to do so will simply create a deliberate error when copying and result in incomplete files that will not work correctly.

A DVD authoring house cannot usually produce discs themselves that have this feature but rather set a flag on the DVD that will instruct the replicating facility to include CSS when manufacturing the disc. This does mean that any DVDs written on recordable discs will not contain the CSS protection, only those manufactured (eg created by SONY).

This type of protection is free from any licencing arrangements and can be added by the DVD author when creating the final disc. Although imperfect and easy to bypass with the correct software it does give the impression of a quality product and that we have done what we can to protect the intellectual content. The resultant disc may be described as Copy Protected. Therefore we should still request this to be added to our DVDs as standard.

The second form of protection is Macrovision (now owned by Rovi), a patented solution that prevents a user from copying the television output signal of a DVD to a video or DVD recorder. This is somewhat dated and has a very limited benefit as if someone were to copy a DVD, they would most certainly use a computer to duplicate the disc as detailed above. Additionally, there is a licencing fee which is payable to Macrovision for every disc manufactured featuring this protection. We should therefore not use Macrovision protection on our discs.



DVD Disc Capacity11

12cm DVDs come in four capacity sizes. A standard DVD-5 can hold roughly 2 hours of high quality video and is both cheap and easy to manufacture. This should be our preferred format wherever possible. A DVD-9 is a dual-layer disc; it has two separate layers sandwiched together and glued one on top of the other, which the laser can read individually (the laser is able to penetrate Layer Zero to read Layer One). DVDs 10 and 18 are double-sided versions of 5 and 9. They are expensive to manufacture and require the user to turn the disc over in order to read the other side of the disc. Due to both sides of the disc being read by a DVD player, it is not possible to have an on-body label. These discs should generally be avoided.

Layer Zero

DVD-5Single-sided, single -layer discCapacity: 4.75 GB

Layer One

Layer Zero

DVD-9Single-sided, dual-layer discCapacity: 8.54 GB

Layer Zero

Layer Zero

DVD-10Double-sided, dual-layer discCapacity: 9.4 GB (2 x 4.75 GB)

Layer Zero

Layer One

Layer One

Layer Zero

DVD-18Double-sided, dual-layer discCapacity: 17 GB (2 x 8.54 GB)

The above diagram shows how the different capacity DVD discs store information. It is important to remember that the more data a disc holds, the higher the manufacturing cost will be.


A common mistake with DVD video is to think of the discs as having a set length in the same way a video cassette did. As such, a DVD video does not literally hold two hours of video, but rather has an unspecified length that will be determined by the overall file size of the video. The higher the data rate of the video (the more information the file contains each second it plays), the fewer minutes will fit on a disc. For simplicity we may say a DVD-5 will hold two hours, but this is not an absolute and your DVD authoring house will be able to easily increase this length, though it will be at the expense of the quality of the video.

The above table gives an overview of the approximate length of video that can be fitted on a DVD disc assuming an average level of quality.

The capacities listed above are assuming a video data rate of approximately 5 Mb/s

2 hours x 60 (there are 60 minutes in every hour) ) = 120 minutes.120 minutes x 60 (there are 60 seconds in every minute) = 7200 seconds (s).7200 seconds x 5 (5 Mb/s is the sample data rate) = 36,000 Megabits (Mb)

36,000 Megabits ÷ 8 (there are 8 bits (b) to 1 byte (B)) = 4500 MegaBytes (MB)4500 MegaBytes ÷ 1024 (A Gigabyte contains 1024 Megabytes) = 4.39 Gigabytes (GB).

Although this works out slightly under for size, we must remember that audio, menus and the DVD file structure will all take up disc space.



DVD Authoring (introduction)13

Unlike videotape, where duplication of the physical units is the only cost to bear, DVD also bears a cost for Authoring, the process whereby video, audio, subtitles and menus are organized together in a very specific way. It is not a case of placing videos onto a disc, but rather a set prescriptive process where only compliant video and audio are added into a rigid structure. All of this is necessary to create a DVD.

During this process the disc navigation is also established; the rules that determine which how the up/down/left/right DVD remote buttons arrows relate to each other and also the destination of each button. In additional to this, navigation information about what happens when each movie ends, or when the menu button on the remote control is pressed is all carefully added. Chapter markers can be positioned in each video track and added and subtitles are correctly prepared and synchronized to the video.

A few basic limitations as to the number of movies and menus per disc exist and these are as follows:

The video and audio tracks in a movie exist separately, even though they will play together as one. This is because DVD supports more than one audio track per movie, as well as multiple subtitle tracks.


The video, audio, subtitles and chapter markers are arranged in the authoring software in a similar manner to that illustrated below. All the assets on a DVD are governed by timecode – a coded reference to hours/minutes/seconds/frames. This code is embedded in the video and it is this that allows the audio and subtitles to synchronize perfectly to it.

An example of how tracks are laid out in DVD authoring software. Each audio and video track is displayed as a long block, with subtitles forming smaller, individual blocks for each title card that appears on screen. Chapter markers appear as vertical lines, running through the tracks.



DVD Navigation15

Although content will vary from project to project, there are some basic rules that should govern all discs we create. A common way of DVD authoring is to begin with a wireframe diagram that details how each menu and each movie interact with each other. This is crucial as it will ensure navigation works in the way you want it to and it also acts as a checklist that all menu buttons are accounted for and the user experience is documented.

Every DVD must have an opening action for when it is placed in a DVD player and that will usually be playing a copyright. Starting with the presentation of the copyright and Cambridge video sting, the below chart demonstrates how a simple two-film disc might be constructed.

Copyright WarningStatic graphicanamorphic 16x9user actions disabled

copyright warning

Cambridge University Press stinganamorphic video: 16x9user actions disabled

Languge Menu (if applicable)Static graphicanamorphic 16x9

Main MenuStatic graphicanamorphic 16x9

Play all

Chapter Menu 1Static graphicanamorphic 16x9Chapter names TBC

Video Title Set 1anamorphic video: 16x9anamorphic 16x9Chapter stops TBC

Chapter Menu 2Static graphicanamorphic 16x9Chapter names TBC

Video Title Set 2anamorphic video: 16x9anamorphic 16x9Chapter stops TBC


User Navigation Assumptions• The disc first play must be the copyright screen. This should have all user commands disabled (remote control buttons).• This should lead automatically into the Cambridge University Press video sting. This should also have all user commands disabled.• This should lead into a language selection screen (if applicable).• This in turn leads to the main menu. Branching off from this will be1. An option to Play All video content.2. A button linking to Chapter Menu 1.3. A button linking to Chapter Menu 2 (if applicable).4. Buttons linking to further Chapter Menus (if applicable).5. A button linking back to the Language Menu (if applicable).• Each Chapter Menu should have buttons linking to the respective chapters as well as a Play All option. They also all link back to the Main Menu.

A well designed DVD will allow the user to navigate the entire disc contents without ever having to press anything other than enter. • On inserting the disc in the player, the user gets directed to the main menu with the first button highlighted.• Pressing enter leads to the first sub-menu with the first button highlighted.• Pressing enter leads to the first movie which, when it ends, takes users back to the first sub-menu with

the second button highlighted.• Pressing enter leads to the second movie which, when it ends, takes users back to the first sub-menu with

the third button highlighted.• This continues through all the buttons on the first sub-menu until the final button which should lead users

back to the main menu with the second button highlighted.• Pressing enter leads to the second sub-menu with the first button highlighted.• Pressing enter leads to the first movie which, when it ends, takes users back to the second sub-menu with

the second button highlighted.• And so on ...



DVD Copyright17

The following copyright notice was forwarded to us by one of our video vendors (Silversun) and has been agreed to by the Legal department. This should be placed on screen for no less than 10 second as the ‘first play’ on every DVD video we create.

COPYRIGHT NOTICE

THE COPYRIGHT PROPRIETORS HAVE LICENCED THE MATERIAL IN THIS DVD/VIDEOGRAM FOR PRIVATE AND DOMESTIC USE ONLY. ANY OTHER USE OF THE WHOLE OR ANY PART OF

THE MATERIAL (INCLUDING ADAPTING, COPYING, ISSUING COPIES, RENTING, LENDING, PERFORMING, BROADCASTING INCLUDING IN A CABLE/TELEPHONY SERVICE OR MAKING

THE SAME AVAILABLE TO OR VIA THE INTERNET OR ANY AUTHORIZING ANY OF THE FOREGOING) IS STRICTLY PROHIBITED.

This is how the copyright appeared on the DVD for Prepare, levels 1-7.

This copyright notice should be directly followed by the Cambridge University Press sting (animated logo). Note that there are two different versions, one with and one without mention of Cambridge English Language Assessment. Both the copyright notice and the sting should have all actions disabled, that is to say the end user cannot skip, pause, fast-forward or otherwise avoid watching them.



DVD Menu Guidelines18

Size and Working AreaAny menu designed for NTSC video must be 720 pixels across (as is the case for all standard definition video) and 480 pixels high (as is the case for NTSC video only). The resolution must be 72dpi (the same as the resolution of televisions and video monitors). Any deviation from these will produce an unworkable menu. The final file format should be an uncompressed TIFF and never a JPG or PSD.

In the above example, a menu has been created in Photoshop with the working dimensions of 534x480. This enables all content to be laid out in such a way as to fill a widescreen image. The menu has then been resized with unconstrained proportions to 720x480 which compresses the image vertically.

Anamorphic CompressionAs previously discussed in the section on aspect ratios, in order to accommodate the wider aspect ratio of modern televisions in a picture that can only be a 4:3 aspect ratio size (in the cast of DVD, 720 pixels wide), the image must be compressed to fit the frame and uncompressed back by the DVD player. Menus therefore need to be created in a widescreen format and then squashed, or anamorphically compressed, in order to display correctly on a widescreen television.

The purpose of anamorphic is really to optimise the screen resolution. If the width of a DVD image is 720 pixels, but a widescreen television displays 1024, then in order to fit the 16:9 image in the DVD frame size, you would need to add black bars at the top and bottom of the image to preserve the aspect ratio. Anamorphic removes this need to stretching the picture to fit the frame and then allowing the television to un-stretch it back to fit. This means that every single pixel in the picture is actually used and not wasted on black bars. This also means the image will not need to be zoomed in on the television, further improving the picture quality. Anamorphic video is often described as being optimised for 16:9 televisions.


FontsAs DVD has a low resolution of 72dpi what we may normally consider to be a large font size (eg 16) will actually be too small for DVD. All text on DVD menus should use a minimum size of 20 point, ideally using a san-serif font so as to avoid thin lines. Any time a line appears on screen finer than two pixels it runs the risk of flickering or pulsing, so pick your fonts and font size with this firmly in mind. Cambridge University Press only holds the license of certain fonts for digital products. Please refer to Content Service’s Fonts for e-product.doc for further details.

Any DVD menu should be tested on a television and never solely on print or on a computer monitor. The high quality of a printer or monitor will give a misleading impression of the quality of the menu.

The first 5% at the edge of the screen should be assumed to be invisible to end users. Although you see it on a computer, you must not assume it will be visible on a television.The next 5% is known as Action Safe. Although this should be visible, it is not advisable to place buttons, subtitles or any other important information here.

5% Invisible Area

5% Action Safe Area

80% Title Safe Area

Safe AreaWith all television sets, the only way manufacturers can ensure that the picture extends exactly out to the border of the screen is to allow the image to extend slightly beyond the border, effectively chopping off the very edge of the image. This is known as overscan. As different television manufacturers produce sets slightly differently, so the amount of overscan varies from set to set. Unlike video games, where overscan can effectively be ‘tuned’ to fit your TV, DVD video cannot and therefore the menus must be configured by the designer to take this into account.

This then leaves the inner 80% of the screen which is known as Title Safe. This is where the content of menus should be placed.


In order to keep menus broadcast safe, output levels need to be altered from 0-255 to 15-240 (no absolute black or white).

A Gaussian Blur of 0.2 should be applied to menus in order to soften the image for television screens.

Broadcast SafeUnlike a computer monitor, a television cannot display extremes in black and white. A pure white (a value of 255 red, 255 green, 255 blue on an 8-bit scale of 0-255) and pure black (a value of 0 red, 0 green, 0 blue on an 8-bit scale of 0-255) contains more contrast than the television can effectively handle. We must strip back some of the dynamic range in the levels.

A thorough explanation of the broadcast safe process can be found here:http://www.adhishyajnik.com/broadcast-709-levels-and-rgb-levels.html

Buttons and Sub PicsIn addition to each menu, it is necessary to create a sub-menu that details the size and shape of the button highlights. These need to be exactly the same size and shape of the menus, though are limited to four colours only (0/0/0 black; 255/255/255 white; 255/0/0 red; 0/0/255 blue). As you will need to reserve one of these for the area outside of the buttons (the transparency) this leaves you only 3 colours to define any button shape. As this for the button, the previous discussion of broadcast legal will not apply.

A common and easy way to create a sub-pic is to use the text from your menu in white against a plain black background (see above).


Plain white text on a black background can be improved and made to look less harsh by using the red and blue to map the grey areas surround the text.

The DVD author can use the 4 colours or black, white, red and blue and use these to define the button highlight areas. Each of these colours can be converted in the DVD authoring software to any RGB colour the author wishes and set to an opacity rating of 0-15.

Converting the sub-pic image to indexed colours allows us to remove variations in shading down to a maximum of 4 (one of these will need to be reserved for the transparent background).

Using the Colour Table we can then manipulate the grey edges of the text into solid red and blue. Although this looks strange, it allow the DVD author to create a softer, more detailed button highlight.

An example of the completed menu with subpic visible (the white text has been turned to a red sing the DVD authoring software.


The navigation for buttons should be based around a logical, intuitive pattern that advances the user forwards and backwards through the buttons in a progressive cycle. On a chapter menu, the vertical navigation should rotate through the buttons top-to-bottom. On horizontal navigation, the buttons should cycle left to right, row by row across the entire screen (see diagram below).

1 2 3

4 5 6

previous main next

Shown above is an example of chapter menu button navigation. The chapter buttons are laid in an obvious sequence, spread over two rows and rising numerically from left to right. On the completed menu, these would have screen-grabs if the respective chapters. Beneath these are options for next and previous (if ap-plicable) and a return to main menu option.

Button

primarydirection

primarydirection

primarydirection

primarydirection

alternativedirection




The desired button navigation can be expressed in the form of a simple diagram (see left).

For each direction, the ideal button direction is show as the primary direction. Should a button not be located in that direction, an alternative direction is also illustrated.

Menu Button Navigation



DVD chapter points23

Cambridge University Press will provide a list of DVD chapter points using the standard SMTPE timecode. When we receive test footage from video producers, they always add burnt-in timecode (BITC) on screen so that we can reference what they have shot. We can then use this to establish our chapter points. Only in-points are necessary as the next chapter provides the corresponding out-point. This will be accompanied with the chapter title and a brief description of the corresponding image. A sample log is listed below:

The number of chapters should practical and appropriate to the source video. Too many chapters can make playback cumbersome and navigation confusing. It is better to keep it simple (i.e., a chapter introducing each topic or unit of work).

The in-point of a chapter should ideally be set a second or two after a scene change if possible as when skipping chapters on a DVD, often the chapter will engage half a second early which can show as a flash-frame of the previous scene. This occurs due to the nature of compressed video (as discussed in a later chapter) and is therefore unavoidable.



DVD Testing24

Any DVD needs to be tested on a standalone DVD player and a television. Relying on computer playback is not an adequate test as the differences in screen size and resolution and even the distance you sit from the screen will not make for a representative experience. Just as something designed for print would need to be seen on a page, a DVD needs to be seen on a television.

The connectors used to transmit the picture between the television and DVD player will have a considerable impact on the picture quality. The lowest quality connections would be RCA Composite Video (all video channels combined into one connector); S-Video (separates out the black and white and colour signals); Component Video (separates the brightness or luminance and the variations in the red and blue channels) and the highest quality would be digital HDMI (transmits the picture and sound as a digital signal directly to the television).

We can never assume that the end user will watch a DVD on high-end computer and should instead test a DVD on the type of equipment that it is essentially designed for. Issues surrounding font size and underscan (as previously discussed) may look much worse on a DVD player and television and it is important to know this so that problems can be overcome prior to design sign-off. Ideally the person testing will sit sufficiently back from the television screen so as to get a model viewing experience.

Model LNS2651D MB382LL/ADate May 13, 2006 October 14, 2008Screen 26” LCD 24”, glossy glass covered screen, LCDPixels 1366 x 768 1920 × 1200, with LED backlightingAspect Ratio 16:9 16:10Contrast Ratio 4000:1 1000:1Response Time 8 ms 14 msBrightness 500 cd/m2 330 cd/m2Colours 12.8 billion 16.7 million True ColourPixel Density (in pixels per inch) 94.3

The above comparison demonstrates how almost every measurement may vary considerably between a computer monitor (in this case an Apple Cinema Display) and a typical television (the same spec as the Samsung model in the testing area). The computer monitor actually has a different aspect ratio to the DVD video (16:10 instead of 16:9) and has a much greater number of pixels in the display.



DVD Final Assets25

When it comes time to call in final files on a DVD-Video project, careful thought needs to be given over to deciding what level of assets we call in. Although the obvious answer seems to be the DVD disc itself, as we will see this alone would prove inadequate. Just as with a book, where calling in a PDF would enable us to print though would provide no possibility to amend later without the Indesign file that created it, a DVD disc has very limited use beyond being a playable disc.

Outputs: Introduction

As discussed previously in the section on Testing, it is crucial that at some point in the projects lifespan a DVD is tested on a DVD disc on a DVD player. It stands to reason then that the DVD-R disc could be considered the final deliverable on a DVD project. This however is not the case for several reasons. Whilst DVD-R compatibility across players and computers is excellent and there would be no real issues with duplicating several copies of a disc on your computer, it is not considered safe enough to manufacture (or replicate) from. Many replicators either refuse outright to create glass master (the physical disc from which all other discs are manufactured) from a DVD-R or require a waiver absolving them of any responsibility should the manufactured discs later turn out to be defective.

DVD-R

In the first wave of DVD authoring, masters were supplied for replication on DLT tapes due to their high capacity (10 - 20 GB), relative low price per GB storage and their ability to be verified bit-for-bit that what is being replicated is 100% what is on the tape. These drives were however expensive in themselves used outdated connections to the computer (SCSI) and more recently have been entirely replaced by using a DDP transfer. This has become possible with vastly increased and improved internet connections. Aspera transferring - a software/hardware system now owned by IBM and used by Apple to upload movies to iTunes - means a process that might have taken a day can now be carried out very quickly. A DDP image can outputted by DVD Authoring software such as Sonic Scenarist or DVD Studio Pro and written directly onto a hard-drive rather than tape.

DDP as a successor to DLT


As with Audio, DVD-Videos are now to be supplied to manufacturing in the DDP format. The DDP folder contains multiple files, none of which are immediately readable by a computer without special software. DDP offers a secure way of transferring data as it contains a checksum - in built error-checking software to ensure the folder contents match 100% what was meant to be written.

The UDF (Universal Disc Format) file, which is a single file that contains all the information that is written to the DVD disc. This disc image technically exists within the DDP and by following certain steps, the UDF can be easily viewed on a computer.

Outputs in CAMS

Outputs DVD-Video

Enfocus Dummy

DVD-Video UDF

(virtual)

CAMS Package

CAMS Request

DDPDDP Files

DDP UDF

The files we add into CAMS under Outputs need to reflect that which we can manufacture from with the same relationship to the final product as a print PDF has to a book. In this regard, the DDP is the file that we need to hold as by holding this asset we can manufacture discs from it with any replicator in the world. The same cannot be said about any other form of Output file(s). Although the DDP itself is not playable on a computer in the same way an ISO or UDF file would be, it can be very easily prepared for playback (see next section).

CHECKSUM_CRC32.TXT ChecksumCONTROL.DAT Lead-in information for mastering. http://www.dvdforum.org/DVD_Cutting_Master/CMF-DVD-6.htmDDVID.DAT Contains the technical details of the disc. http://www.dvdforum.org/DVD_Cutting_Master/CMF-DVD-2.htmgear.log Log file from the DDP creation software (Gear Pro).IMAGE.DAT The entire UDF-Bridge volume for the disc. http://www.dvdforum.org/DVD_Cutting_Master/CMF-DVD-7.htmVOBTABLE.DAT specfices the start and end sectors of the VOB files on the disc. http://www.dvdforum.org/DVD_Cutting_Master/CMF-DVD-5.htm

DDP Format and Structure

required files


Burning a disc or playing video from a DDP

Once a DVD project is complete it will be necessary to load both the final DVD disc and also the supporting assets into CAMS. The disc itself will be provided by the DVD production company in the form of an DDP file. This will usually be transmitted to us electronically in time to pass to manufacture, though it could even written to a dsic as a DDP rather than a DVD-Video. Although unreadable in itself you can easily turn this DDP into an playable volume by following these steps:

Open the DDP folder in Finder and find IMAGE.DAT. This will be the largest file and the one that contains the DVD-Video disc information.Open Toast Titanium and go to ‘Copy’ in the main header section. Select ‘Image File’ and then drop and drag the DAT file into Toast.

The image file is now available to either burn to a DVD disc or mount as a virtual disc to your hard drive. Press ‘Mount’. Double click on the disc to open it. Open the Video TS

folder and you will see all the disc contents.The disc will appear on your desktop with the same appearance and properties as an actual disc.

Double click on the disc to open it. Open the Video TS folder and you will see all the disc contents. You should not attempt to play any of these individual files, but rather play the Video TS folder itself with VLC player software.


assets which form part of the DVD disc

DVD ROMContent

DVD Project

Video Files(M2V)

Audio Files(AC3)

Subtitle Files(STL)

Menu Files(TIFF)

Sub-Picture Files(TIFF)

Source Files in relation to DVD

Deciding what source files we need for a video project is a little more complicated than for most other product types. There are such a wide number of files and, as is often the case, the files that made those files and so on. If we were to call in quite literally every file that constitutes a ‘source’ of the final DVD product, we may well be looking at the contents of multiple computers (the computer that edited the video; the computer that created animated content; the computer that created the DVD menus; the computer that authored the DVD disc etc.) and

would ultimately lead to hard drives full of assets that we don’t necessarily need, do not have the software to open and modify and also don’t have the knowledge of how to manipulate. Clearly then, care must be taken to differentiate between assets that are worth holding on to at this end and those that are best left with the post-production house in case of future editions and changes.

Source Files: Introduction

Having designated the DDP of the DVD as the output, the logical first place to start is all the assets that are gathered together for the process of DVD authoring. As the authoring process irrevocably changes the files that are the building blocks of the DVD (static menus are converted from single uncompressed images to compressed movie files), it would make perfect sense to have a copy of every asset file that goes into the DVD authoring software and the DVD project file that links them all together. If such a set of files were available to us, then we would have the ability to open the disc project, add or remove any individual elements such as movie tracks, menus or subtitles and then create a new compile of the disc and therefore a new gold master disc that could be manufactured from.

Even without the DVD authoring software necessary to open and modify the DVD project file, we would have the oppertunity to approach a vendor who did have this software and make the requested changes through them.One particualr benefit would be for adaptations where the video is unchanged, but perhaps a new audio langauge, menu langauge or subtitle language could be added.

Item File TypeDVD Project The DVD authoring

software project file.Video Files video onlyAudio Files corresponding audio

track(s)Subtitles STL, SRTMenu Files both static and

motion menus.Sub-Picture The button highlight

on menus.DVD ROM Content

Various


DVD ROMContent

DVD Project

Video Files(M2V)

Audio Files(AC3)

Subtitle Files(STL)

Menu Files(TIFF)


High-De�nitionOutput from

Edit Suite

SubtitleTranscript

Menu Source Files

(PSD)

Sub-PictureSource Files

(PSD)

requiredassets whichdo notform part ofthe DVD disc

required files


Complete hi-resolution outputs of each finalised video track in either of the following formats:

Edit Suite Export FormatAVID DNxHR HQXif edited on AVIDhttps://en.wikipedia.org/wiki/DNxHD_codec

APPLE HD PRO-RES 4-2-2 HDif edited on Apple Final Cut Pro (FCP)https://en.wikipedia.org/wiki/Apple_ProRes

Which format we receive will depend entirely on the edit suite used by the post production house.

High-Definition Source Files


DVD ROMContent

DVD Project

Video Files(M2V)

Audio Files(AC3)

Subtitle Files(STL)

Menu Files(TIFF)



Edit Suite

SubtitleTranscript

Menu Source Files

(PSD)


(PSD)


The video used in the DVD authoring, whilst important, is a medium quality highly-compressed version, supplied out of necessity for DVD in a format that does not lend itself particualrly well to editing or conversion. As all new video projects are now shot and edited in high-definition, this compressed DVD MPEG-2 video represents a fraction of the potential video quality.

What is needed is a high-definition output of each movie file in the project as exported from the edit suite. The exceptionally high quality of this file would allow any amount of conversion to other quality settings and formats, giving us an unprecedented ability to future-proof each video we create. For professional post-production houses, the editing software will either be one of the products developed by Avid (such as Media Composer) or Apple’s Final Cut Pro. Both will output a movie that conforms to the high-def standard of 1920x1080 pixels and typically a bit-rate of around 20 - 28 Mb/s and a 10-bit sample depth.

required files


The below diagram also makes reference to the source files that created the menus themselves. Whilst this would in an ideal world be desirable, in theory this could lead to a particulalry large number of files, with Photoshop files, stock images, After Effects projects and more. With any video project, there will be hours, or even days worth of footage that is shot but not used in the final edit. These are known as the rushes and may consist or alternate or unusable takes or even dropped scenes that were filmed but that did not make it to the final edit. The combined size of these files would be substantial and it’s also worth remembering that each of these shots would have been dropped from the final edit for a reason. It is not therefore recommended that we ask videos producers to supply rushes to us.

Source Files out of scope


DVD ROMContent

DVD Project

Video Files(M2V)

Audio Files(AC3)

Subtitle Files(STL)

Menu Files(TIFF)



Edit Suite

SubtitleTranscript

Menu Source Files

(PSD)


(PSD)


The assets discussed will require a hard-drive to transport to us due to the sheer size of data involved. High definition video alone equates to roughly 150-210 megabytes (MB) per minute. It would be impracticle to receive video source files through any other method. Additionally, the hard drive itself will allow for easy access to the files once we have them without the need for lengthy CAMS downloading, and for supply to third parties if conversion work etc is needed.

Delivery of Source Files


DVD-Video Project

Source DVD-Video MPEG-2 VideoCAMS Package

CAMS Request

Source Files in CAMS

Menus

Dolby AC3 AudioMovies

TIFF Files

RAW

Final edited video

SubtitlesSTL Files

Once obtained, these assets can then be added to CAMS. The diagram to the right is a suggestion of how assets might be loaded based on a file structure that would relate closely to the way the assets should be assembled by the DVD author when creating the disc. It separates the files that actually intended for the DVD from those used to create those assets.

In addition to the final MPEG-2 compressed video file (which is stated earlier is a lossy format) we might have a high-definition copy of the final edit of the video which would allow us to easily repurpose the video for anything requiring a higher level of quality than that of DVD.

Movies

Stock ImagesImages

MPEG-2 Video Dolby AC3 Audio

It is suggested that this same asset structure is used on the hard drive provided by the video producer which will create a consistent approach to assets and greater ease when adding packages to CAMS. I would also suggest that the hard drive from the supplier also contain the DDP images of the DVD-Videos so that everything is together in one place. A policy on where the hard drive will be kept once we have it has yet to be agreed upon but my suggestion would be a locked cabinet in Content Services and a system whereby anyone wanting access to one of the drives would have to sign it out for a limited period of time.



Subtitles32

At the most basic description, subtitles involve superimposing a layer of image over the video track. Commonly this image takes the form of words that match what is heard on the audio track. You will find a lot of issues discussed below will look very similar to the chapter on DVD menus. This is because on a DVD menu, the button highlight is in fact technically a subtitle file itself and therefore has exactly the same features and the same limitations. Before reading further, it would be a good idea to take a quick look here at the previous section. It would also make sense at this point to introduce a few key features of subtitles ahead of the detailed discussion of the subtitle file itself.

Subtitles: Introduction

This is a very different scenario from subtitles on videotape, where the subtitle had to be permanently recorded (or burnt in) to the image, making it unremovable. Subtitles on a digital product, are stored in the Alpha Channel, a separate element of the video stream used solely to contain transparent images. This channel can be made visible or invisible thereby turning the subtitles on and off.

Subtitle

Subtitle

Alpha Channel

Video track with Alpha channel enabled

Video track


Anti-AliasingLike any video image, a subtitle is made up of tiny squares (pixels). However as subtitles consist of words (usually in white) against a transparent background, the thickness of the words can cause an issue. Televisions struggle with anything less than a few pixels in width and especially so if this is combined with extreme light and dark areas such as black and white. As a result, the edges of the words will tend to appear very stark and blocky. At worst, this can appear very flickery and render the text harder to read.

The first picture shows the letter ‘A’ against a plain black background (on a subtitle, this black would be transparent). On the second picture, enlarging the ‘A’ reveals the jagged edge where the image has no alternative to being either black or white. On a diagonal line this leads to a stepped, jagged appearance. However, by blurring the edges, we create areas of grey that hide the absolute distinction between black and white. Ironically it is this blurring that will allow the image to display sharper on a monitor.If a subtitle were simply displayed as either plain white or pure transparent (thereby using two colours white=white; black=transparent) then the edges of the subtitles would appear quite sharp and jagged. By using the red and blue channels (subtitles can use these four colours: red, blue, black, white) we can define the edges of the letters in red and blue, which the DVD player can then display in shades of grey, thereby softening the edges of the letters - see the step-by-step below:

Plain white subtitles against a black background. Using the colour table in Photoshop, 2 shades of anti-aliasing have been added in blue and red.

Superimposing the subtitle over an image, the anti-aliasing can be seen, first displaying in blue and red.

The anti-aliasing converted to shades of grey, producing a softer subtitle font that will be less prone to the aliasing effects of a television/monitor.


TimecodeTimecode is inherently linked to the video file and because digital video is measured in frames, so therefore must subtitles be. Timecode is a clock measured in hours/minutes/seconds/frames that underlies all subtitle files and is used primarily to determine when a subtitle should begin and end. There are two types of timecode in relation to subtitles: zero-based and asset-based. Zero-based is so-called as it assumes every movie file starts at time zero: zero hours, zero minutes, zero seconds and zero frames (00:00:00:00). Asset-based timecode looks instead to the video file which can contain an embedded timecode that is taken from the edit-suite file or from a tape source. For the purposes of this chapter we will assume that all projects are utilising zero-based timecode.

Would you classify that as a design problem or a launch problem?

If, for example, we wanted the subtitles to appear at one minute and thirty seconds into the video and stay on screen for four and a half seconds, we would express the timecode values thus:

00:01:30:00 , 00:01:34:15

Looking at the above example, the start time skips the hour value (leaving it at zero); starts at one minute (01); thirty seconds (30); and no frames (00) making it at the thirty second mark exactly. The end point if four seconds (34) and half a second (15) later. In this example I am assuming the video to be in NTSC which runs at just under 30 frames per second, therefore half a second would be 15 frames.


Subtitles can be created in a number of formats and there is no one right or wrong way to create them. It is true to say that no single file will fulfil every purpose, especially as technologies change and evolve. It is true to say however, that whilst different, the various subtitle files have key characteristics in common. At its most basic, a subtitle must consist of at the very least, the following information:

the subtitle start time (in point) , the words of the subtitle , the subtitle end time (end point)

If we look again then at the previous example and add words to the subtitle, we should see a clearly defined in-point, out-point and the wording of the subtitle:

Subtitle Formatting

00:01:30:00 , 00:01:34:15 , Would you classify that as a design problem or a launch problem?


The issue remaining is that whilst we have specified what should be displayed and when it should be displayed we have as yet not defined how it should be displayed. The example above contains characters in italic and also a line break in a specific place. It also has the subtitles appearing as is customary at the bottom of the screen. How a computer or DVD player would know these things also needs to be defined. It can be said then, that as long as we have this key information, the rest is a matter of using the correct syntax. DVD as an established format is unable to adapt or change as this would render older players incapable of playing newer discs and therefore offers something of an refreshing change by having a set of fixed conventions that must always be adhered to for the lifetime of the format. DVD also represents the main way we provide video to market; it both the highest quality video we provide and also the only way we provide video as a standalone product. It makes sense then if subtitles are written initially with DVD syntax in mind.


The following information constutes the file header information that globally affects all the subttiles.

FontCommandsThe font commands set all commonly used font properties.$FontName: Sets the name of the font the subtitles use. Use the family name as it appears in the Fonts window, which can be opened by clicking ‘Show Fonts’ in the toolbar or choosing Format>Fonts>ShowFonts.$FontSize: Sets the size of the font.$Bold: Selects the bold version of the font (if available). Enter ‘True’ to select the bold version and ‘False’ to disable it.$Italic: Selects the italic version of the font (if available). Enter ‘True’ to select the bold version and ‘False’ to disable it.$Underlined: Adds an underline to the subtitle text. Enter ‘True’ to turn on the underline and ‘False’ to turn it off.

Colour CommandsThe color commands choose the colours from the default subtitle Colour Palette to apply to the subtitle. The values range from 0 to 15.$ColorIndex1: Chooses the text colour.$ColorIndex2: Chooses the text’s outline1 colour.$ColorIndex3: Chooses the text’s outline2 colour.$ColorIndex4: Chooses the background colour.

Contrast CommandsThe contrast commands set the opacity of the colours assigned to the subtitle.The values range from 0 (transparent) to 15 (opaque).$TextContrast: Sets the opacity of the text colour. $Outline1Contrast: Sets the opacity of the text’s outline1 colour.$Outline2Contrast: Sets the opacity of the text’s outline2 colour.$BackgroundContrast:Sets the opacity of the background colour. This is usually set to 0, unless you are using a graphic that does not use white as the background colour.

The Spruce Technologies subtitle file is still very much industry standard despite the sale of Spruce to Apple some 15 years ago. Like all subtitle formats that exist for DVD video, an STL is centred around frame based timecode - time is measured in increments of hours/minutes/seconds/frames - with a frame being the smallest measure of a second and a rate dictated by the video standard (PAL has 25 frames per second; NTSC has 29.97). STL can be written either using specialist subtitling software or even by using Textedit or Notepad. Unlike other subtitle files for other products, a DVD subtitle file also contains information regarding the fonts used and the positioning of the subtitle on screen. As Spruce was bought by Apple in order to redesign their DVD Studio Pro software, the manual for that package details the formatting of STL files in considerable detail. Listed below is a complete guide to the syntax necessary in the creation of STL.

Spruce Technologies Subtitle (STL) File

Header


Position CommandsThese commands control the subtitle’s position.$HorzAlign: Sets the subtitle’s horizontal alignment. You can enter ‘left’, ‘center’, or ‘right’.$VertAlign: Sets the subtitle’s vertical alignment. You can enter ‘top’, ‘center’, or ‘bottom’.$XOffset: Allows you to modify the subtitle’s horizontal position from where the horizontal alignment placed it. The values you enter are in pixels, with positive values moving the subtitle to the right and negative values moving it to the left.$YOffset: Allows you to modify the subtitle’s vertical position from where the vertical alignment placed it. The values you enter are in pixels, with positive values moving the subtitle up and negative values moving it down.

Display CommandsThese commands control how a subtitle displays.$ForceDisplay: Forces the subtitle to display regardless of whether subtitles are turned on by the DVD player. You can enter ‘True’ (subtitles are forced to display) or ‘False’ (subtitle display is controlled by the DVD player).$FadeIn: Sets the fade time used to gradually dissolve the subtitles on. Enter a value in frames.$FadeOut: Sets the fade time used to gradually dissolve the subtitles off. Enter a value in frames.

Graphics File CommandUse this command if this subtitle file uses graphics files in addition to, or in place of, text entries.$SetFilePathToken: Sets a token that you use on any subtitle entries that contain a graphics filename instead of subtitle text. The entry must be such that it never appears in normal text or filenames. Thenormal convention is to surround the text with dual anglebrackets, making it easier to locate within an STL file. For example, you could use ‘_Graphic_’.

Timeline Command By default, the timecode values in an STL file are in reference to the videostream’s zero-based time, which starts at 00:00:00:00. You can use this command to reference the file’s timecode values to the videostream’s asset-based timecode.$TapeOffset: Controls how the timecode values in the STL file are referenced to the videostream. You can enter ‘False’ to reference them to the stream’s zero-based timecode (which begins at 00:00:00:00), or ‘True’ (the default setting) to reference them to the asset-based timecode. Note: When referenced to the asset-based timecode, the Track Inspector’s Track Offset settingis ignored—only the actual asset’s timecode is used.

Individual SubtitlesControls Embedded in the Subtitle TextYou can embed several controls in the text part of the entries. These controls can force a linebreak and turn on and off the bold and italic font versions.

Line BreaksSubtitle text does not automatically wrap at the edges of the screen. To make it fit you must either reduce the font size or break it into multiple lines by inserting line breaks. To insert a line break, add the vertical pipe character (|) to the text. 00:00:12:04 , 00:00:14:12 , Lemurs are the bullies | of the wild. In the above example, the text will appear as two lines.


00:01:30:00 , 00:01:34:15 , Would you classify that as a ÎdesignÎ problem | or a Îlaunch problemÎ?


Bold, Italic, and Underlined CharactersYou can embed controls that change the state of the bold and italic attributes within the text part of an entry.

To change the state of the bold setting, insert an up arrow followed by the letter “B” (^B). 00:00:12:04 , 00:00:14:12 , Lemurs are ^Bbullies^B.In the above example, the bold status changes for the word “bullies” only. If the bold attribute had not already been activated, “bullies” would change to bold. If the bold attribute had already been activated, “bullies” would not be bold. To change the state of the italic setting, insert an up arrow followed by the letter “I” (Î). You can also use bold and italic together. 00:00:12:04 , 00:00:14:12 , Lemurs are ^BÎbullies^BÎ.In the above example, the word “bullies” has both the bold and italic attributes change.

To add an underline to portions of the text, insert an up arrow followed by the letter “U” (Û). You can use the underline along with the bold and italic settings.

Referencing Graphics Files in STL Subtitle FilesAn STL subtitle file can contain a mix of text subtitle entries and references to graphics files. You must use the $SetFilePathToken command in the file before any lines that reference a graphics file. $SetFilePathToken = _Graphic_ 00:00:12:04 , 00:00:14:12 , _Graphic_RabidLemur.tif 00:00:16:14 , 00:00:19:08 , _Graphic_MooseLemur.tif Important: Do not add spaces between the token (_Graphic_inthisexample)andthefilename. The STL subtitle file and the graphics it references must be in the same folder. And, just like the other assets that you import into your project, the graphics files must not be moved, renamed, or deleted until after you build your project.

This is the example subtitle, this time with the correct syntax added to produce the italics and the linebreak.


Subtitles for other product typesAs discussed previously, no single subtitle file will be suitable for all product types. However, with a little reworking, the STL files provides an excellent starting point for other formats. As it contains the in-point, out-point and wording of the subtitle, all that is required is to adapt this information to suit the different product type.

VTT Subtitles for Presentation PlusAs discussed previously, no single subtitle file will be suitable for all product types. However, with a little reworking, the STL files provides an excellent starting point for other formats. As it contains the in-point, out-point and wording of the subtitle, all that is required is to adapt this information to suit the different product type.

The above shows the same subtitles as both an STL file (left) and VTT file - the current format used on Presentation Plus (right). Although the wording of the subtitles is exactly the same, the STL contains a header describing global attributes such as font, position, colour and outlines. It also displays the timecode in NTSC, so each second is broken into increments of 29.97. The VTT contains no such header, uses quite different syntax to describe the italic text and crucially each second is split into thousandths of a second.


• The STL file begins with some basic fomatting information (font, font size, position) predeeded by a string ($).

• Each subtitle contains an in and out point. The time measurement is seperated by colons.

• Timecode is expressed as hours/minutes/seconds/frames.

• The in-point, out-point and the wording of the subtitle are all seperated by commas.

WEBVTT

0:01:41.862 --> 0:01:44.320Here, the men respect the tigers.

0:01:44.434 --> 0:01:45.680The tigers are safe.

0:01:47.028 --> 0:01:49.760They would prefer to see the tigers in the wild…

0:01:49.931 --> 0:01:51.314...but it’s too dangerous.

0:01:55.200 --> 0:01:58.880”So basically, what your monastery does is, when a tiger is sick,

0:01:58.880 --> 0:02:01.405and someone has a tiger they bring it to the monastery?”

0:02:01.400 --> 0:02:02.057”Yeah.”

0:02:02.050 --> 0:02:03.497”And How many tigers do you have now?”

0:02:03.490 --> 0:02:04.982”Ah, we have ten now.”

0:02:04.980 --> 0:02:06.788”Ten tigers. Are they a lot of work?”

0:02:06.845 --> 0:02:09.840”Yeah. Every day they eat a lot!”

0:02:10.228 --> 0:02:12.422But the tigers are not pets.

//Font select and font size$FontName = Arial$FontSize = 50

//Character attributes (global)$Bold = FALSE$UnderLined = FALSE$Italic = FALSE

//Colors$ColorIndex1 = 0$ColorIndex2 = 1$ColorIndex3 = 2$ColorIndex4 = 3

//Contrast Control$TextContrast = 15 $Outline1Contrast = 15$Outline2Contrast = 7$BackgroundContrast = 0

//Position Control$HorzAlign = Center$VertAlign = Bottom$XOffset = 0$YOffset = 100

//Subtitles00:01:41.26 , 00:01:44:10 , Here, the men respect the tigers.00:01:44:13 , 00:01:45:20 , The tigers are safe.00:01:47:01 , 00:01:49:23 , They would prefer to see the tigers in the wild…00:01:49:28 , 00:01:51:09 , …but it’s too dangerous.00:01:55.06 , 00:01:58:26 , Î”So basically, what your monastery does is, when a tiger is sick,Î00:01:58:26 , 00:02:01:12 , Îand someone has a tiger they bring it to the monastery?”Î00:02:01:12 , 00:02:02:02 , Î”Yeah.”Î00:02:02:01 , 00:02:03:15 , Î”And How many tigers do you have now?”Î00:02:03:15 , 00:02:04:29 , Î”Ah, we have ten now.”Î00:02:04:29 , 00:02:06:24 , Î”Ten tigers. Are they a lot of work?”Î00:02:06:25 , 00:02:09:25 , Î”Yeah. Every day they eat a lot!”Î00:02:10:07 , 00:02:12:13 , But the tigers are not pets.

DVD Subtitle (STL File) Presentation Plus Subtitle (VTT File)

• The VTT file beings with a header indentifying the file type (WEBVTT).

• Each subtitle contains an in and out point. The time measurement is seperated by periods.

• Timecode is expressed as hours/minutes/seconds/thousandths of a second.

• The in-point, out-point of the subtitle are seperated by two hypens and a square bracket, forming an arrow. The wording of the subtitle appears on the next line.

All that be required to change the formats would be to remove the header information from the STL file and reformat the reminder. The arrows could easily be copied and pasted over the commas separating the timecode. The formatting indicator for Italics would also be very easy to change in Word using a simple find and replace action.


In consultation with one of our video suppliers, it has been confimred by an STL file can be converted to a VTT file by using Word macros to handle the chnage in formatting and the conversion from frames per seond to thousandths of a second.

The main difficulty would be in reformatting the timecode from frames into thousandths of seconds. The hour/minute/second measurements would all be unchanged as it isn’t the time that is being altered, only the increments that make up each second. Ultimately a second is still a second.

Listed below are the forulae to convert between the two measurement systems for the 3 most common frame rates (24fps, 25fps and 29.97 fps).

Convert 24 fps to 1000/s(1000 ÷ 24 = 41.666) therefore multiply the nunber of frames by 41.666

Convert 25 fps to 1000/s (1000 ÷ 25 = 40) therefore multiply the nunber of frames by 40

Convert 29.97 fps to 1000/s (1000 ÷ 29.97 = 33.666) therefore multiply the nunber of frames by 33.666

Convert 1000/s to 24 fps(a ÷ 1000 x 24 = b) divide thousandths by 1000 then multiply by number of frames

Convert 1000/s to 25 fps(a ÷ 1000 x 25 = b) divide thousandths by 1000 then multiply by number of frames

Convert 1000/s to 29.97 fps(a ÷ 1000 x 29.97 = b) divide thousandths by 1000 then multiply by number of frames

STL to VTT

VTT to STL

ResourcesFor an in-depth analysis of the STL file format, please refer to page 467 of the Apple DVD Studio Pro 4 User Guide.smb://groupshares/ELT PC Share/OPERATIONS TEAM/PRODUCTION UNIT/STAFF FOLDERS/Matt/Documents/Video/PDF/DVD_Studio_Pro_4_User_Manual.pdf

http://www.bodenzord.com/archives/79

https://documentation.apple.com/en/dvdstudiopro/usermanual/index.html#chapter=19%26section=13%26tasks=true

Timecode conversion



This section deals specifically with the process of digitised video, how it is created and the factors affecting it. The previous section dealt with DVD as a format, which in itself is constructed around a form of digitised video, specifically MPEG-2. This section looks instead at the video in itself.

Digital Video Introduction42

For a number of years, the type of video we work with would have been shot on analogue tape. This is turn would have been edited from one professional video deck to another, both of which were controlled by an elaborate control panel, these pieces forming an edit suite. This type of editing was destructive - each edit had to be copied from one tape to another and any changes to the edit could only be made by erasing the previous version. Additionally this method was prone to quality loss as each copy was inferior to the previous copy, with all copies subject to the potential loss that came with a fragile, easily damaged tape format.

Since the early 1990s this has become superseded by editing on a computer, or Nonlinear editing (NLE). Instead of copying tape-to-tape, editing was carried out first by copying the tape to a computer, which then was used to assemble footage in the correct order. Unlike the previous method, this was nondestructive - removing a shot from an edit did not throw it away and it could always easily be put back. An editor could create as many different versions as one of our editors could create numerous Word files, and move between them just as easily. To begin with, this was still mastered back to tape, though by the end of the 1990s, DVD arrived.

New projects are shot directly onto digital storage media like hard-drives and memory cards so the journey from camera to computer is simply a matter of copying files. Once digitally edited, the content will be sold back to the public digitally in one form or another. With the advent of DVD discs replacing videotapes, downloadable videos on the internet, CD-ROMs and even streaming videos, there is almost no video now that doesn’t exist in a digitised form. This chapter will cover some of the formats of digital video, covering the basic building blocks of how it is made, before moving on to how to manipulate and change the settings of existing video.


As we progress into digital video, terms such as quality and compression are going to be used regularly and it’s worth taking time now to consider some basics of quality vs functionality as all digital video makes a compramise along these lines.

A good example of the need for efficient and clever compression can be found by looking at an MP3 player, such as an iPod.

iPod Name Capacity (GB) Estimated SongsiPod nano 4th Gen 8 GB, 16 GB 2000, 4000

In their sales materials, Apple gave an estimate of the number of songs you might expect to fit on an iPod. Clearly this estimate is subject to several factors such as song length. The longer each song, the fewer songs would fit (if each song were twice as long as Apple’s estimate, the total number you could fit on an iPod would be halved).

Just as important however is the data rate- something that will be explored in greater detail later. For now, we can liken this to audio quality and once again, the greater this quality, the fewer the songs that will fit. Clearly the whole point of having an iPod was to be able to carry lots of songs around, so the idea of lowering that number very much runs contrary to the purpose of the device. Of course, we can also argue that there’s no point having all these songs if they all sound terrible. They key here is one of optimization - to find a compromise whereby we are willing to sacrifice quality in favour of a gain elsewhere - such as the number of songs that will fir on a device.



Up until now this handbook has focussed largely on DVD and therefore by definition MPEG-2, the video format upon which DVD is predicated. Digitised video has existed in a number of different formats and qualities over the years. The Motion Pictures Experts Group are a ‘working group for the development of international standards of compression, decompression, processing and coded representation of moving pictures, audio and their combination’1 Over time, they have defined the specifications for a number of digital video formats starting with MPEG-1.

1 Quantel The Digital Fact Book. Eleventh Edition.

Video Codecs44

A new video standard

Analogue/LaserDiscLaserDisc was the original video on a disc format, dating back to 1978, thereby predating both VHS tapes and Audio CDs. A premium high-end product based around a 12 inch disc (similar to vinyl record) although with an analogue video track and uncompressed audio. This specification meant only 60 minutes of video could fit on one side of a disc.

VCD/MPEG-1MPEG-1 was designed as the format for video CDs (also known as VCD). Unlike LaserDisc however, the video and audio was digitised and heavily compressed in order to still fit 60 minutes to one disc, although a 12cm disc rather than a 12 inch one.In order to achieve this on a relatively small 650 MB capacity CD-ROM, video was limited to a bitrate of 1.2 Mb/s (around a quarter of that of DVD). The picture size was also very low with dimensions of 352x288 pixels (half of DVD). Quality was therefore substantially lower than it’s predecessor, but hugely more convenient. In 1991, Philips attempted to capitalise on this new format by releasing the CD-i players, a forerunner to the modern DVD player and video games console. These functioned as standalone VCD players, though as a format this never really caught on and video on disc didn’t really enter the mass public market until the introduction of DVD.


DVD/MPEG-2The next generation of disc player first hit the shelves in the late 1990s and brought with it a new type of video compression technology. MPEG-2 would act as the successor to MPEG-1 offering a larger frame size (720x576 PAL / 720x480 NTSC) and a video data rate that averaged around 5 Mb/s. The increase in quality, coupled with a disc format that could hold roughly 8 times that of the CD brought digital video into every home. MPEG-2 received further exposure in the UK with the advent of Terrestrial Digital Video Broadcasting (DVB-T), or Freeview as it’s commonly marketed. Using the well established MPEG-2 compression, the picture quality once again seemed a vast improvement on the previous analogue broadcasting.

H.264/MPEG-4MPEG-4 is the latest incarnation of the video compression co-created by the Motion Pictures Experts Group and finalised in 2003. A versatile, powerful format it can be used in many applications for a whole range of video sizes and qualities.

At the higher end of the spectrum, Blu-Ray discs utilize MPEG-4 Part 10 Advanced Video Coding (AVC) for the compression of video at high data rates (in excess of 20 Mb/s) and in a larger picture size (full high-definition runs at 1920x1080 pixels). The true versatility of this codec also allows for video to also be encoded at low data rates and smaller picture sizes and as such it now represents the bulk of the content on video streaming sites such as YouTube, Vimeo and the iTunes Store.

Also known as H.264, the AVC codec’s purpose was efficiency. Although revolutionary at the time, DVD with it’s MPEG-2 codec proved very limited at handling video below a certain data rate and it’s flaws could be very apparent with blockiness evident on video with a large amount of motion, such as sports.

The next section of this handbook will be dealing with MPEG-4 as a format and the ways in which we can encode video into this revolutionary format.

Dive into HTML5. Chapter 5: Video on the Webhttp://diveintohtml5.info/video.html

H.264 Levels and Profileshttp://blog.mediacoderhq.com/h264-profiles-and-levels/

Motion Picture Experts Group AVC/H.264 Licence Termshttp://www.mpegla.com/main/programs/avc/Documents/avcweb.pdf



Video Compression46

A key aspect to digitised video is compression. Unlike audio where an uncompressed recording is still of sufficient size to add to a disc or for a consumer-quality machine to play (CD audio is uncompressed), the complexity of video information means that the file size would be far too great to work with uncompressed, which would also be too demanding on a computer to play.This chapter details with how video is constructed in a digital format and the key terms involved with measuring the size and quality of that video. It also deals with how the file size of the video is reduced, which is the key aspect to compression.

1 2 3 41 2 3 41 1

720 pixels

480 pixels

1

The frame rate equals the number of images that appear per second.Cinema plays at 24 frames-per-second (fps). PAL video plays at 25 fps and NTSC video at 29.97 fps.

Frame Rate

If every one of these frames were represented as an image, this would take up a lot of room on your computer (like 25 JPG images for every single second of video). To reduce this size, only a few evenly-spaced frames in this sequence are self-contained pictures. These are called Keyframes. The remaining frames in-between the keyframes are not self-contained but instead are based on the information contained in the last keyframe and adding only specific information relating to what has changed since that keyframe. Essentially therefore, it is calculating change based on motion. The in-between frames are known as Intra-frames and come in two types: Predicted frames (which estimate change based on the previous adjacent frame) and Bidirectional frames (which estimate change based on previous and future frames).

The sequence of frames between each keyframe is know as a Group of Pictures, or GOP. The frequency of the number of keyframes in relation to the number of frames per second is called a GOP pattern or GOP rate.

1 2 3 41 2 3 41 1

720 pixels

480 pixels

1

GOP Pattern


1 2 3 41 2 3 41 1

720 pixels

480 pixels

1Each frame of digital video, just as with a digitised still image, is comprised of a large number of tiny coloured squares (pixels) which when seen together form the whole image. The greater the number of pixels, the larger the picture size will be and also, potentially the more detailed the picture will be. We measure the picture size of video in pixels, for example a DVD may be 720 pixels across by 480 pixels in height (720x480), whereas hi-definition is 1920x1080 pixels.

Picture Size

1 2 3 41 2 3 41 1

720 pixels

480 pixels

1

Although the picture size is important as it determines the size and quality of a video, of equal if not greater importance is the data rate. This is what determines how much information is written into every second of video. A bigger picture size needs more information to accompany the extra pixels, otherwise we might simply see a picture that fills the screen, but fills it with blockiness and an unwatchable image. Similarly if the picture size is small, then increasing the data rate can’t and won’t change the fact that the image is not constructed of many pixels and therefore cannot hold a high level of detail, and will simply make the video bigger but not better.

There are no hard and fast rules as to how high a video data rate should be. This is due to several reasons. Firstly, video can utilise any one of a number of different compression types (known as codecs). the different types bring with them differing efficiencies as to how well they can process video at a given data rate. Some are without a doubt better than others. Secondly, video compression is always a balancing act between file size and quality. Whilst we it might seem logical to strive to the highest quality, we have to balance this against file size which could determine how many minutes of video can fit on a disc, or even whether a video will even play on the target device.

A video should have a quality that reflects the picture size and also the intended use. If a video is intended for a mobile device, then the data rate needs to be low so as to reflect the limited storage capabilities of that device. If a video is designed for streaming, you need to consider the internet connection of the person watching that video. Once you have a quality that is fit-for-purpose, anything beyond that simply makes the file bigger but not better.

Data Rate



Video Quality / Bitrate Calculating48

With many digital products, there is often a need to ensure the final size of a given file does not exceed a certain amount. Performing a bit calculation will enable you to accurately estimate the size a of a file before you convert it.

In order to create digital content that is suitable for purpose it is always recommended to perform a bitrate calculation. In some instances, we may only be able to accommodate a limited amount of data (a DVD disc will only hold 4.75 GB of data)

Making content fit size a set size

We need our file to be under 4MB.4 MB (x8) = 32 Mb32 Mb (x1024) = 32,768 kb32,768 kb (÷166 seconds) = 197.39759 kb/s

Therefore in order to create a file that is under 4MB in size it would have to be under 197 kilobits per second (kb/s).

Measuring bitrate from an file

Our file is 320 kb/s320 kb/s (÷8) = 40 kB/s40 kB/s (÷1024) = 0.039 MB/s0.039 MB/s (x 166 seconds) = 6.48 MB

In this instance, the file would be too big.

Let’s assume a video clip is 2 minutes 46 seconds long. To work out the bitrate per second, we will first need to know how many seconds there are, which we can achieve by dividing the minutes by 60 and adding the minutes to that number. In this example, there are 166 seconds.

1GB (one gigabyte) Contains 1024 MB (one thousand and twenty four megabytes)

1 MB (one megabyte) Contains 1024 kB (one thousand and twenty four kilobytes)

1 kB (one kilobyte) Contains 1024 B (one thousand and twenty four bytes)

1 B (one byte) Contains 8 b (eight bits)

How to estimate video file size


However, this needn’t be seen as a bad thing in itself. No one video file should be expected to take the place of any other, nor should we expect one file to do every job perfectly. Each video file produced should be with a specific purpose in mind and with the system requirements and restrictions of the delivery medium firmly in mind. We shouldn’t want to put high definition video into an eBook anymore than we would want to use a paper bag to carry bricks. To do so would be to fail to see the differences between the two and to fail to understand that each has it’s uses and limitations.

The clarity of image is an obvious area we can measure quality, though not the only one we should measure. A file that takes up too much room on a iPad or that takes too long to download should also be seen as a failure of quality. One size does not fit all. Although someone might conceivably play an eBook through an external display or interactive whiteboard, we need to acknowledge that we cannot prepare equally for every eventuality with how someone might use a product. Playing back video on a large screen is why we create a DVD disc; an eBook is created with other uses in mind. We need to accept that there will be a difference between the quality of the video between different media, or we run the risk of creating unwieldy products that burden devices or systems with an excessive amount of data needlessly.

Video qualityIt is worth acknowledging that video has issues intrinsically linked to it that make it somewhat uniquely problematic among digital assets. Audio can be adequately compressed almost to a level that is almost indistinguishable from the uncompressed form and graphics and images can usually be scaled down in size by using clever compression or a different format that supports lower size without noticeable problems. Video, by contrast, produces files of a large size (25 frames of images, plus accompanying audio every second) where bringing the size down also noticeably reduces the quality of its appearance.

The very nature of video compression means creating a new file that is inferior in quality to the file it was created from. A DVD for instance is a poor imitation of the final edit created by the video editor in the post-production house.

The video files on all these products are

not interchangeable!


Video Compact Disc (VCD)Disc Capacity: 650-700 MBVideo Codec: MPEG-1 Picture Size: 352x288Video Data Rate: 1141000 b/s (1.2 Mb/s approx)Audio Codec: MPEG-1 Layer 3 (MP3)Audio Bitate: 224 kb/sAudio Sample Rate: 44.1 mHz

Digital Versatile/Video Disc (DVD)Disc Capacity: 4.75- GBVideo Codec: MPEG-2Picture Size: 720x576 (PAL), 720x480 (NTSC)Video Data Rate: Variable (typical 4-6 Mb/s)Audio Codec: MP3 / Dolby Digital AC3 / DTS / UncompressedAudio Bitate: Variable (typical 224 kb/s for MP3/AC3)Audio Sample Rate: 48 mHz

Blu-Ray Disc (BVD)Disc Capacity: 25/50 GB MBVideo Codec: MPEG-4/H.264Picture Size: 1920x1080Video Data Rate: Variable (typical 20-25 Mb/s)Audio Codec: MP3 / Dolby Digital AC3 / DTS / UncompressedAudio Bitate: Variable (typical 224 kb/s for MP3/AC3)Audio Sample Rate: 48 mHz

Sample video specifications for referenceBelow is a list of common formats that detail the specifications of those formats. There are areas where these are fixed, though I’ve also tried to indicate where these can be varied.



Handbrake: Introduction51

Handbrake is a piece of freeware introduced in its current form in 2007 and which runs on both the PC and Mac platforms. Unlike most commercial video editing packages that are designed to output high quality video for broadcast television, film or video but which struggle at lower resolutions, Handbrake is specifically designed to crunch video down to a low file size. Sample video encoding tests have demonstrated that Adobe Media Encoder CS5.5 - the program that performs the video encoding when exporting from both Adobe Premiere and Adobe After Effects - is not suited to low data-rate encodes. The results produced are disappointing, featuring a highly pixelated picture and unreadable on screen text.

This is extremely important as one of the constant struggles with digital video is balancing quality and compatibility. It is all too easy to focus simply on quality, resulting in a ‘bigger is better’ view, though in reality this is not the case. Making a file bigger does not improve the quality proportionally to size, as after a point you are simply making the file bigger only. This can also lead to major problems, such as with internet streaming video where a larger file may struggle to play without lots of stopping and starting (buffering). Please refer to the section on Quality for further discussion.

Handbrake is designed to use a specific video format, MPEG-4. Following on from MPEG-2 (the format that forms the backbone of every DVD video) MPEG-4 was designed to allow for web use rather than just broadcast. It is also much more efficient than its predecessor, meaning that the same quality can be achieved in a much smaller file size.

Encoding video using the proposed specifications can be surprisingly easy. This is largely due that we are only really focusing on altering several key settings: video codec, video data-rate, picture size, audio codec, audio sample rate and audio data rate. This chapter will examine these settings in some detail, giving an explanation of the key terms.The next section will then crucially also provide a series of easy-to-use presets that will produce video suitable for Cambridge University Press products. Full details and software download links can be found at the official website:http://handbrake.fr/

As of the time of writing the current latest version of Handbrake for Mac is version 0.10.1 x86_64. It would be worth checking you have this version installed before using this guide as screenshots and settings may be different in previous versions.

Upgrading to the latest version

What is Handbrake?


Source. This is used to browse for the video file you wish to convert. Various features of the software will be locked until you have selected a file

Start/Pause. Starts or pauses encoding of the current clip in the main window.

Add to Queue. Enables you to park the selected video into a queue which you can then add multiple other titles to and then encode them together in a row.

Show Queue. This pop-up box is where items added to the queue appear. This has its own start and pause buttons which set the queue rendering instead of individual clips (see 2 below)

Picture Settings. Opens the Picture Settings Pop-Up Window which gives the ability to redefine or fine-tune the picture size (see 3 below).

Preview Window. This pop-up window gives you a preview of how the settings you have chosen will affect the video clip you are working on (see 4 below).

Activity Window. Displays an ongoing list of the processes your computer is performing when encoding video. This is not needed for everyday work (see 5 below).

Toggle Presets. Enables visibility of the Presets panel located to the right of the main window (see 6 below).

1

2

3

45

6

The main interface window (see 1 below) is where you can select a clip, apply audio and video settings to that clip and finally encode that clip. Most of the settings required will be found in this main window, though the additional windows have their functions. The diagram below shows you the windows and the buttons required to view them.

Handbrake: Main Interface

All of the settings detailed in this section are stored in the established presets that can be imported into Handbrake, and it is therefore possible to use the software without ever changing any of the settings. However, by detailing the process by which video is encoded and by which the presets were created, it is possible to highlight the steps you would need to go through in order to create a new preset should a new project have specific requirements that cannot be met by the existing standards.


Handbrake can encode video either from an unprotected DVD-Video disc (see previous chapter) or from individual video files. The process for choosing the source file is largely similar.

Source

From DVD-VideoIt is recommended to first copy the contents of the DVD-Video to your hard drive as the process is much slower if working directly from a disc.

Press the Source button and search for the Video-TS folder. All of the individual movie tracks on the disc will be made available to copy from.

Next, choose the movie track you wish to encode. Pressing the drop-down menu for Title will reveal the list of tracks. You will need to work out which is these is the correct one, which will be easier if you know the length of the video. If not, you may need to try a few. The list will include the copyright and the DVD menus in addition to all the video tracks.

Depending on how the DVD-Video was authored, the movie you want may either be a track in its own right, or may exist as part of a larger movie. If this is the case, then you can use the next drop-down menu, Chapters, to specify the start and end chapter points of the video you want to encode. If in doubt, use the Preview Window to visually check the video track you have selected. With any DVD video you know that the picture size will be 720 pixels across (whether PAL or NTSC) and at around 5Mb/s video data rate. This is your starting point to compress down from.

Single fileIt the clip you are encoding from is a single video file such as an MP4 or AVI file, then the settings of this source clip could be pretty much anything potentially. In order to reduce the size, you must first establish what you are reducing it down from.

First, open the video file in Quicktime Player and Window/Show Movie Inspector (⌘-i; CTRL-i) to reveal the properties of the file. Under Format, you will find the details of the video codec, picture size, audio codec, audio sample rate and audio channels. Make a notes of these settings as you will need them in the next stages.


The video tab is where most of the important work occurs. This is where the quality and file-size of your encoded video will be established and controlled.

Video Codec: When working with MP4 as the file type, the default video codec is H.264 (see relevant chapter for an explanation of this compression type)

Framerate (FPS): You can specify how many frames per second you want your video to run at. This can be used for extreme file size reduction (halving or quartering the frame rate) or standards converting from PAL to NTSC (or vice versa). Changing the frame rate can result in issues such as motion judder and speed issues. As a computer can play back PAL or NTSC equally, it is best not to alter the frame rate and leave on same as source.

Quality: For best results, change this to Average Bitrate and type in the exact kilobits per second data rate you want. As the purpose of this software is essentially size reduction for video, the bitrate setting should be programmed as low as is possible to create a video file that is fit for purpose. Please refer to the chapter on bit-rate calculating for further info.

You can improve the quality greatly by selecting 2-pass encoding which enable Handbrake to process your video twice: once to analyse the complexity of the clip and ascertain which moments have the greatest data requirement and then a second pass that encodes the video based on these findings. Turbo first pass speeds up the analysis stage and should be selected.

It cannot emphasised enough that there is no specific setting that is necessarily right for video. As a rule, the smaller the file, the lower the picture quality will be, but the higher the compatibility will be across different host media (CLMS, eBook etc). A data rate should only be set as high as it needs to be, anything beyond this just makes the file bigger and therefore more problematic when adding into the host media.

Lowering the data rate should be used skilfully in conjunction with other settings. A low data rate will look

much worse across a large picture size as there will be more pixels requiring that data each frame. Better to lower the picture proportionally to the data rate and let a computer scale the image up to fill a screen.

Encoder Options: You can chose from a number of specific presets here, which can be useful if that is a requirement of the video project. At present, none of Cambridge University Press’ products use these standards. Please refer to the section on H.264 levels and presets.

Video


The second tab contains the options for controlling the audio compression.

Track: If encoding from a DVD source, you may find the DVD contains multiple audio tracks that are synchronized to the video. You can choose which track you want with your final file here.

Codec: You can specify which form of audio compression technology you wish to use. MP3 and AAC are the most common types of audio you would want to use, with AAC (Advanced Audio Codec) offering a better quality reproduction at the same data rate. You can chose the option for Passthru if you do not want to recompress your audio but rather use the existing audio.

Mixdown: Most video clips we work with will be in stereo, which is the default for music or film, though as there are two channels (left and right) it will take up more room. If your clip only has speech and no music or sound effects, you can save room by changing this to mono.

Samplerate: This governs the number of times per second the audio is analysed by a computer. A typical rate for this would be 44.1, which means 44,100 times every single second (or 44.1 mHz). If size is going to be an issue on a file, you might want to lower the data rate, in which case lowering the sample rate will make the lower quality less evident. A rate of 22.050 would be appropriate for low data rates.

Bitrate: The bitrate (as discussed in previously) allows you to reduce the final file size by lowering the amount - and therefore quality - of information in every second. For an average stereo track, a rate of 128 kb/s would be entirely appropriate. If you need to reduce the size of your file still further, you can reduce this quality down as much as possible until you feel the sound of the audio is beginning to suffer.

It is important to remember though that the bitrate (or data rate) should not be reduced in isolation, but rather in combination with the other settings. If you have a low bitrate, consider reducing the sample rate (the number of times per second the audio is read (or sampled) by the computer, and also whether a reduction in the audio channels from stereo to mono might be possible.

Gain: You can use this to increase the audio levels for particularly quiet clips. DRC: Dynamic Range Compression represents a more effective way to govern the overall volume of your

audio. Rather than simply raising or lowering the quality of the audio (as with Gain), DRC reduces the amount of variance between the highest and lowest sounds in the audio, thereby creating a more centred, even audio volume level throughout.

Audio


The final two tabs, Subtitles and Chapters are used largely when working with DVD and allow you to specify individual chapter points in a movie and also to include a subtitle track into the video (if there is one available in the original source).

Subtitles and Chapters

Although this is a pop-up window rather than one of the tabs, Picture Settings is one of the most important settings windows in the program. This is the window where we can set the picture frame size, essentially determining at what size the video will fit on screen. It is important to remember that any video will have both a picture size and a display size.

Picture Settings

The image on the right shows a video that has been encoded in Handbrake and is playing in Quicktime Player.The Format, as shown in the Inspector window below indicates that the video has a size of 853 x 480 (as it has a 16:9 aspect ratio). This is the size the video was encoded to in Handbrake and indicates the actual number of pixels that comprise the image size.We also see there is a setting for Current Size and that this states the video is 556x313. This is because the video playback window has been resized on my computer screen - in this case, resized down. It could also have been resized up if I was watching the video in full screen. This then is a measurement of how the video is playing back, not of the actual pixels in the video.

You will not be able to make the picture size larger than the picture size of your source file.

The aspect ratio can be calculated by the following method:

Width % 16 x 9 = Height.eg 1920 pixels % 16 (width) = 120 x 9 (height) = 1080 pixels

1920x1080 is therefore a 16:9 aspect ratio.



Handbrake Presets57

I have created five custom presets, all based around H.264 video with a 16:9 aspect ratio, which together will provide for a wide range of qualities for different applications.

For Presentation Plus, eBooks and LMS content, the most common settings we would use are 360p or, if more quality is needed, 480p. These two settings produce video that has perfectly adequate quality for the aforementioned applications without unnecessary size.

In reality, there will be little need for the 240p setting unless internet bandwidth were a real issue. Similarly at this stage, we would have little use for either the 720p or 1080p settings as we do not produce hi-definition products. However, what these do show is just how high the data rate that has been used in the past for products such as Presentation Plus or eBooks is incredibly unsuited to those applications.

The 5 Presets

Cambridge University Press Digital and Streaming Video Specifications 2012

7

Cambridge University Press Proposed Settings Due to the highly impressive compression capabilities of the H.264 video codec, coupled with the increasingly universal move away from Flash, I would recommend using H.264 for all video formats, therefore all five file varieties will be MPEG-‐4.

Although designed to echo YouTube’s standards and specifications, these could be used for any purpose from CD-‐ROMs and SCORM packs though to internet streaming and video downloading.

General Format 240p 360p 480p 720p 1080p File Extension MP4* Data Rate 284kb/s 416kb/s 546kb/s 1.328Mb/s 2.128Mb/s

Video Picture Size 426x240 640x360 854x480 1280x720 1920x1080 Aspect Ratio 16:9 Frame Rate 29.97fp/s** Fields/Frequency Progressive Scan / 60 MHz Video Codec H.264 Advanced Video Coding (AVC) Video Data Rate 220Kb/s 320Kb/s 450Kb/s 1.2Mb/s 2.5Mb/s

Audio Audio Codec Advanced Audio Coding (AAC)*** Channels Stereo (L/R) Sample Rate 22.050kHz 44.100kHz Audio Data Rate 56kb/s 96kb/s 128kb/s * Although YouTube uses a Flash container for the lower bit-‐rate settings, there is no reason why this

needs be the case. For true cross-‐compatibility and future proofing, MP4 is to be used exclusively. ** As the required video standard for DVD is to be NTSC, a move designed to promote the maximum

compatibility across territories, an NTSC frame-‐rate has similarly been chosen for the streaming video. *** There is no reason to use MP3 as the audio codec for the basic setting when AAC has already been

established as more efficient with lower data rates. These settings are currently being tested on both the L2 platform and also InkToWeb.

These presets are available for importing directly into Handbrake and can be found here:ELT PC Share/OPERATIONS TEAM/PRODUCTION UNIT/STAFF FOLDERS/Matt/Documents/Video/Handbrake/16-9 Presets


480p is what has been used on Face2FaceeBooks

480p is what has been used on PreparePresentation Plus

xxxCLMS

xxxxxx


4:3 videoThis will be older video shot for The Press. This video can be easily converted into a new version as long as the aspect ratio remains unchanged. In order to turn this into 16:9 we would need to add black bars to either side of the image (pillarboxing) in order to turn a square into a rectangle (see guide on page xx)

Use Handbrake setting A

16:9 anamorphic video (flag not set)This will be newer video shot of 16:9 and optimised for DVD. As DVD only accepts a 4:3 image, 16:9 content is stretched to fit the frame and then un-stretched by software during playback. When playing back on a computer, the image will look stretched and distorted.

Use Handbrake setting B

16:9 anamorphic video (flag set)

This will be newer video shot of 16:9 and optimised for DVD. As DVD only accepts a 4:3 image, 16:9 content is stretched to fit the frame and then un-stretched by software during playback. When playing back on a computer, the image will look correct and display wide.

Use Handbrake setting A

16:9 videoThis will be new video shot for The Press that has an aspect ratio of 16:9.

Use Handbrake setting C

16

:9 W

IDE

16:9

AN

AMO

RPHI

C

4:3

Settings for other aspect ratios



H.264 ProfilesThe standard includes the following seven sets of capabilities, which are referred to as profiles, targeting specific classes of applications:

• Baseline Profile (BP): Primarily for lower-cost applications with limited computing resources, this profile is used widely in videoconferencing and mobile applications.

• Main Profile (MP): Originally intended as the mainstream consumer profile for broadcast and storage applications, the importance of this profile faded when the High profile was developed for those applications.

• Extended Profile (XP): Intended as the streaming video profile, this profile has relatively high compression capability and some extra tricks for robustness to data losses and server stream switching.

• High Profile (HiP): The primary profile for broadcast and disc storage applications, particularly for high-definition television applications (this is the profile adopted into HD DVD and Blu-ray Disc, for example).

• High 10 Profile (Hi10P): Going beyond today’s mainstream consumer product capabilities, this profile builds on top of the High Profile—adding support for up to 10 bits per sample of decoded picture precision.

• High 4:2:2 Profile (Hi422P): Primarily targeting professional applications that use interlaced video, this profile builds on top of the High 10 Profile—adding support for the 4:2:2 chroma subsampling format while using up to 10 bits per sample of decoded picture precision.

• High 4:4:4 Predictive Profile (Hi444PP): This profile builds on top of the High 4:2:2 Profile—supporting up to 4:4:4 chroma sampling, up to 14 bits per sample, and additionally supporting efficient lossless region coding and the coding of each picture as three separate color planes.

In addition, the standard contains four additional all-Intra profiles, which are defined as simple subsets of other corresponding profiles. These are mostly for professional (e.g., camera and editing system) applications:

• High 10 Intra Profile: The High 10 Profile constrained to all-Intra use.

• High 4:2:2 Intra Profile: The High 4:2:2 Profile constrained to all-Intra use.

• High 4:4:4 Intra Profile: The High 4:4:4 Profile constrained to all-Intra use.

• CAVLC 4:4:4 Intra Profile: The High 4:4:4 Profile constrained to all-Intra use and to CAVLC entropy coding (i.e., not supporting CABAC).

H.264 Profiles and Levels60


H.264 LevelsLEVEL NUMBER MAX

MACROBLOCKS PER SECOND

MAX FRAME SIZE (MACROBLOCKS)

MAX VIDEO BIT RATE (VCL) FOR BASELINE, EXTENDED AND MAIN PROFILES

MAX VIDEO BIT RATE (VCL) FOR HIGH PROFILE

MAX VIDEO BIT RATE (VCL) FOR HIGH 10 PROFILE

MAX VIDEO BIT RATE (VCL) FOR HIGH 4:2:2 AND HIGH 4:4:4 PREDICTIVE PROFILES

EXAMPLES FOR HIGH RESOLUTION @FRAME RATE(MAX STORED FRAMES)IN LEVEL

1 1485 99 64 kbit/s 80 kbit/s 192 kbit/s 256 kbit/s 128×[email protected] (8) 176×[email protected] (4)

1B 1485 99 128 kbit/s 160 kbit/s 384 kbit/s 512 kbit/s 128×[email protected] (8)176×[email protected] (4)

1.2 6000 396 384 kbit/s 480 kbit/s 1152 kbit/s 1536 kbit/s 320×[email protected] (7)352×[email protected] (6)

1.3 11880 396 768 kbit/s 960 kbit/s 2304 kbit/s 3072 kbit/s 320×[email protected] (7)352×[email protected] (6)

2 11880 396 2 Mbit/s 2.5 Mbit/s 6 Mbit/s 8 Mbit/s 320×[email protected] (7)352×[email protected] (6)

2.1 19800 792 4 Mbit/s 5 Mbit/s 12 Mbit/s 16 Mbit/s 352×[email protected] (7)352×[email protected] (6)

2.2 20250 1620 4 Mbit/s 5 Mbit/s 12 Mbit/s 16 Mbit/s 352×[email protected](10)352×[email protected] (7)720×[email protected] (6)720×[email protected] (5)

3 40500 1620 10 Mbit/s 12.5 Mbit/s 30 Mbit/s 40 Mbit/s 352×[email protected] (12)352×[email protected] (10)720×[email protected] (6)720×[email protected] (5)

3.1 108000 3600 14 Mbit/s 17.5 Mbit/s 42 Mbit/s 56 Mbit/s 720×[email protected] (13)720×[email protected] (11)1280×[email protected] (5)


4 245760 8192 20 Mbit/s 25 Mbit/s 60 Mbit/s 80 Mbit/s 1280×[email protected] (9)1920×[email protected] (4)2048×[email protected] (4)

4.1 245760 8192 50 Mbit/s 50 Mbit/s 150 Mbit/s 200 Mbit/s 1280×[email protected] (9)1920×[email protected] (4)2048×[email protected] (4)


5 589824 22080 135 Mbit/s 168.75 Mbit/s 405 Mbit/s 540 Mbit/s 1920×[email protected] (13)2048×[email protected] (13)2048×[email protected] (12)2560×[email protected] (5)3680×1536/26.7 (5)

5.1 983040 36864 240 Mbit/s 300 Mbit/s 720 Mbit/s 960 Mbit/s 1920×[email protected] (16)4096×[email protected] (5)4096×[email protected] (5)

Source:http://blog.mediacoderhq.com/h264-profiles-and-levels/