Video. Overview b Using video. b How video works? b Broadcast video standards. b Analog video. b Digital video. b Video recording and tape formats. b

VideoVideo

OverviewOverview

Using video.Using video. How video works?How video works? Broadcast video standards.Broadcast video standards. Analog video.Analog video. Digital video.Digital video. Video recording and tape formats.Video recording and tape formats. Shooting and editing video.Shooting and editing video. Optimizing video files for CD-ROM.Optimizing video files for CD-ROM.

VideoVideo

Video is the most recent addition to the elements of Video is the most recent addition to the elements of multimediamultimedia

It places the greatest demands on the computer and It places the greatest demands on the computer and memory (using about 108 GB per hour for full motion)memory (using about 108 GB per hour for full motion)

Often requires additional hardware (video Often requires additional hardware (video compression board, audio board, RAID - Redundant compression board, audio board, RAID - Redundant Array of Independent Disks- for high speed data transfer)Array of Independent Disks- for high speed data transfer)

Using VideoUsing Video

Carefully planned video can enhance a presentation (eg. Carefully planned video can enhance a presentation (eg. film clip of JFK, better than an text box of same message)film clip of JFK, better than an text box of same message)

Before adding video to a project, it is essential to Before adding video to a project, it is essential to understand the medium, how to integrate it, its limitations, understand the medium, how to integrate it, its limitations, and its costsand its costs

Using Digital VideoUsing Digital Video

Digital video has replaced analog as the method of choice Digital video has replaced analog as the method of choice for making and delivering video for multimedia.for making and delivering video for multimedia.

Digital video device produces excellent finished products at Digital video device produces excellent finished products at a fraction of the cost of analog.a fraction of the cost of analog.

Using Digital VideoUsing Digital Video

Digital video eliminates the image-degrading analog-to-Digital video eliminates the image-degrading analog-to-digital conversion.digital conversion.

Many digital video sources exist, but getting the rights can Many digital video sources exist, but getting the rights can be difficult, time-consuming, and expensive.be difficult, time-consuming, and expensive.

Video ClipsVideo Clips

Ways to obtain videoWays to obtain video• shoot new film clips with a digital camcordershoot new film clips with a digital camcorder

• convert you own video clips to digital formatconvert you own video clips to digital format

• acquire video from an archive - often very expensive, difficult acquire video from an archive - often very expensive, difficult to obtain permissions or licensing rightsto obtain permissions or licensing rights

Be sure to obtain permission from anyone you film or Be sure to obtain permission from anyone you film or for any audio you use!for any audio you use!

How Video WorksHow Video Works

Light passes from an object through the video camera lens Light passes from an object through the video camera lens and is converted into an electrical signal by a CCD and is converted into an electrical signal by a CCD (charge-coupled device).(charge-coupled device).

High quality cameras have 3 CCDHigh quality cameras have 3 CCD Signal contains 3 channels of color information (red, green, Signal contains 3 channels of color information (red, green,

blue) and a synchronization pulse.blue) and a synchronization pulse.


If each channel of a color signal is separate it is called RGB If each channel of a color signal is separate it is called RGB ( preferred)( preferred)

A single composite of the colors and sync signal is less A single composite of the colors and sync signal is less preciseprecise

A typical video tape has separate tracks for audio, video, A typical video tape has separate tracks for audio, video, and controland control

( See p. 180)( See p. 180)

Video BasicsVideo Basics


The video signal is magnetically written to tape by a The video signal is magnetically written to tape by a spinning recording head following a spinning recording head following a helicalhelical pathpath

Audio is recorded on a separate straight trackAudio is recorded on a separate straight track The control track regulates the speed and keeps the The control track regulates the speed and keeps the

tracks aligned as the tape plays/records.tracks aligned as the tape plays/records.

Video BasicsVideo Basics

Broadcast Video StandardsBroadcast Video Standards

NTSC PAL SECAM HDTV

Six different formatsSix different formats

Aspect ratio is 16:9Aspect ratio is 16:9


National Television Standards Committee (NTSC):National Television Standards Committee (NTSC):• These standards define a method for encoding information into These standards define a method for encoding information into

electronic signal that creates a television picture.electronic signal that creates a television picture.

• It has screen resolution of 525 horizontal scan lines and a scan rate It has screen resolution of 525 horizontal scan lines and a scan rate of 30 frames per second.of 30 frames per second.


NTSCNTSC- National Television Standards Committee - - National Television Standards Committee - 1952, (“never the same color”)1952, (“never the same color”)

1 frame = 525 horizontal lines every 1/30 second1 frame = 525 horizontal lines every 1/30 second 2 passes - odd/even lines, 60/second2 passes - odd/even lines, 60/second

(60 Hz)(60 Hz) interlacing - to reduce flickerinterlacing - to reduce flicker


Phase Alternate Line (PAL) and Sequential Color and Phase Alternate Line (PAL) and Sequential Color and

Memory (SECAM):Memory (SECAM):

– PAL has a screen resolution of 625 horizontal lines and a PAL has a screen resolution of 625 horizontal lines and a

scan rate of 25 frames per second.scan rate of 25 frames per second.

– SECAM has a screen resolution of 625 horizontal lines and SECAM has a screen resolution of 625 horizontal lines and

is a 50 Hz system.is a 50 Hz system.

– SECAM differs from NTSC and PAL color systems in its SECAM differs from NTSC and PAL color systems in its

basic technology andbasic technology and broadcast method.broadcast method.


Advanced Television Systems Committee (ATSC) Advanced Television Systems Committee (ATSC) Digital Television (DTV):Digital Television (DTV):

– This digital standard provides TV stations with This digital standard provides TV stations with sufficient bandwidth to present four or five Standard sufficient bandwidth to present four or five Standard Television (STV) signals or one High Definition TV Television (STV) signals or one High Definition TV (HDTV) signal.(HDTV) signal.

– This standard allows for transmission of data to This standard allows for transmission of data to computers and for new Advanced TV (ATV) computers and for new Advanced TV (ATV) interactive services.interactive services.


Several incompatible standards:Several incompatible standards: NTSC (US, Japan, many other NTSC (US, Japan, many other

countries)countries)

PAL - (United Kingdom, parts of PAL - (United Kingdom, parts of

Europe, Australia, South Africa)Europe, Australia, South Africa) SECAM - (France Russia, few others)SECAM - (France Russia, few others) HDTV - ( US ) - newest technologyHDTV - ( US ) - newest technology


HDTV- High Definition Television now available, allow HDTV- High Definition Television now available, allow viewing of Cinemascope and Panavision movies with viewing of Cinemascope and Panavision movies with aspect ratio 16:9 ( wider than high) (See p. 184)aspect ratio 16:9 ( wider than high) (See p. 184)

Twice the resolution, interlaced formatTwice the resolution, interlaced format Digitized then compressed for transmissionDigitized then compressed for transmission


4: 3 Aspect Ratio4: 3 Aspect Ratio


16: 9 Aspect Ratio16: 9 Aspect Ratio

Integrating Computers and Integrating Computers and TelevisionTelevision

Television video is based on Television video is based on analoganalog technology and technology and international broadcast standardsinternational broadcast standards

Computer video is based on Computer video is based on digitaldigital technology and other technology and other image display standardsimage display standards

DVD and HDTV merges the twoDVD and HDTV merges the two

Analog VideoAnalog Video

• Analog television sets remain the most widely installed Analog television sets remain the most widely installed platforms for delivering and viewing video.platforms for delivering and viewing video.

• Television sets use composite input. Hence colors are Television sets use composite input. Hence colors are

less pure and less accurate than computers using RGB less pure and less accurate than computers using RGB

component.component.

• NTSC television uses a limited color palette and NTSC television uses a limited color palette and

restricted luminance (brightness) levels and black restricted luminance (brightness) levels and black

levels.levels.

Analog VideoAnalog Video

• Some colors generated by a computer that display fine Some colors generated by a computer that display fine on a RGB monitor may be illegal for display on a NTSC on a RGB monitor may be illegal for display on a NTSC TV.TV.

• While producing a multimedia project, consider whether While producing a multimedia project, consider whether it will be played on a RGB monitor or a conventional it will be played on a RGB monitor or a conventional television set.television set.

Video Overlay SystemVideo Overlay System

To display analog video (TV) images on a computer To display analog video (TV) images on a computer monitor, the signal must be converted from analog to monitor, the signal must be converted from analog to digital form ( Where else does this conversion digital form ( Where else does this conversion commonly take place?)commonly take place?)

A special digitizing video overly board is required for A special digitizing video overly board is required for the conversionthe conversion

Produces excellent quality, full screen, full motion Produces excellent quality, full screen, full motion video, but costly.video, but costly.

Video Overlay SystemVideo Overlay System

Many companies use computer based training (CBT) Many companies use computer based training (CBT) systemssystems

These require a computer and monitor cabled to a TV and These require a computer and monitor cabled to a TV and video disc player. video disc player.

Overlay boards allow the video disc to be controlled by the Overlay boards allow the video disc to be controlled by the computer and display the images on the computer screen.computer and display the images on the computer screen.

Video Capture BoardsVideo Capture Boards

Video overlay boards can capture or digitize video Video overlay boards can capture or digitize video frames and play them back as QuickTime MPEG and frames and play them back as QuickTime MPEG and AVI movies.AVI movies.

Some also include audio input and sound management Some also include audio input and sound management to interleave sound and imagesto interleave sound and images

Some also offer compression and accelerate digitizing, Some also offer compression and accelerate digitizing, or support NTSC video.or support NTSC video.

Differences Between Computer Differences Between Computer and TV Videoand TV Video

Computer scan refresh rate = 480 lines/secComputer scan refresh rate = 480 lines/sec Computer scan is progressive ( non-interlaced) at 66.67 HZ Computer scan is progressive ( non-interlaced) at 66.67 HZ

or higheror higher TV scans at 525 (or 625) lines/sec, with interlacing at a TV scans at 525 (or 625) lines/sec, with interlacing at a

frame rate of 60 Hzframe rate of 60 Hz

Interlacing EffectsInterlacing Effects

The TV electron beam actually “draws all the odd line, The TV electron beam actually “draws all the odd line, then all the even lines, interlacing themthen all the even lines, interlacing them

On a computer (RGB) monitor, lines are painted one On a computer (RGB) monitor, lines are painted one pixel thick and are not interlaced. Displayed on a TV pixel thick and are not interlaced. Displayed on a TV they “flicker” because they appear in every other field. they “flicker” because they appear in every other field. To avoid this avoid very thin lines and elaborate serifs.To avoid this avoid very thin lines and elaborate serifs.


TV broadcasts an image larger than the screen so that the TV broadcasts an image larger than the screen so that the “edge” of the image is against the edge of the screen. This “edge” of the image is against the edge of the screen. This is called is called overscanoverscan

Computer images are smaller than the screen area (called Computer images are smaller than the screen area (called underscanunderscan) and there is a border around the image) and there is a border around the image

Computers and VideoComputers and Video


When a computer screen is converted to video the outer When a computer screen is converted to video the outer edges do not fit on the TV screen only about 360-480 edges do not fit on the TV screen only about 360-480 lines of the computer image are visible.lines of the computer image are visible.

Avoid using the outer 15% of the screen for graphics, or Avoid using the outer 15% of the screen for graphics, or titles for use on TVtitles for use on TV

Use the safe title area ( See p. 184)Use the safe title area ( See p. 184)

Video ColorVideo Color

Color reproduction and display are also different in TV Color reproduction and display are also different in TV and computers monitorsand computers monitors

Computers use RBG component video and produce more Computers use RBG component video and produce more pure colorpure color

NTSC TV uses a limited color palette and restricted NTSC TV uses a limited color palette and restricted luminance (brightness) and black levelsluminance (brightness) and black levels

Working with Text and Titles for Working with Text and Titles for Video ProductionsVideo Productions

Use plain, bold, easily read fontsUse plain, bold, easily read fonts Use light color text on a dark backgroundUse light color text on a dark background Avoid color combinations like yellow/violet, blue/orange Avoid color combinations like yellow/violet, blue/orange

which “vibrate”which “vibrate” Avoid black or colored text on white backgroundAvoid black or colored text on white background


Make lines and graphics at least two pixels wideMake lines and graphics at least two pixels wide Use parallel lines and boxes sparingly and draw them with Use parallel lines and boxes sparingly and draw them with

thick linesthick lines Avoid “hot” colorsAvoid “hot” colors Keep graphics and titles in the safe screen areaKeep graphics and titles in the safe screen area


Bring titles on slowly and let them remain on the screen Bring titles on slowly and let them remain on the screen sufficiently long, fade outsufficiently long, fade out

Avoid “busy” screens- use additional pages insteadAvoid “busy” screens- use additional pages instead

Digital VideoDigital Video

Digital video architecture.Digital video architecture. Digital video compression.Digital video compression.

Digital Video ArchitectureDigital Video Architecture

Digital video architecture consists of a format for encoding Digital video architecture consists of a format for encoding and playing back video files by a computer.and playing back video files by a computer.

Architecture includes a player that can recognize and play Architecture includes a player that can recognize and play files created for that format.files created for that format.

Digital Video CompressionDigital Video Compression

Digital video compression schemes or “codecs” ( Digital video compression schemes or “codecs” ( cocoder/der/decdecoder) is the algorithm used to compress (code) a oder) is the algorithm used to compress (code) a video for delivery.video for delivery.

The codec then decodes the compressed video in real-time The codec then decodes the compressed video in real-time for fast playback.for fast playback.

Streaming audio and video starts playback as soon as Streaming audio and video starts playback as soon as enough data has transferred to the user’s computer to enough data has transferred to the user’s computer to sustain this playback.sustain this playback.

Video CompressionVideo Compression

To store even a 10 second movie clip requires the To store even a 10 second movie clip requires the transfer of an enormous amount of data in a very short transfer of an enormous amount of data in a very short timetime

30 seconds of video will fill a 1 GB hard drive30 seconds of video will fill a 1 GB hard drive Typical hard drives transfer about 1MB/second and CD- Typical hard drives transfer about 1MB/second and CD-

ROMs about 600K/secondROMs about 600K/second

Video CompressionVideo Compression

Full motion video requires the computer to deliver the data Full motion video requires the computer to deliver the data at 30 MB/second more than today’s PCs and MACs can at 30 MB/second more than today’s PCs and MACs can handlehandle

Solution- use video compression algorithms or Solution- use video compression algorithms or codecscodecs Codecs compress the video for delivery and then decode it Codecs compress the video for delivery and then decode it

for playback at rates from 50:1 to 200:1for playback at rates from 50:1 to 200:1

Video Compression & StreamingVideo Compression & Streaming

CodecsCodecs ( such as MPEG, JPEG) use ( such as MPEG, JPEG) use lossy compressionlossy compression schemesschemes

StreamingStreaming technologies are also used to provide technologies are also used to provide reasonable quality , low-bandwidth on the WEBreasonable quality , low-bandwidth on the WEB

Playback starts as soon as enough data have been Playback starts as soon as enough data have been transferred to the user’s computer instead of waiting transferred to the user’s computer instead of waiting for the whole file to downloadfor the whole file to download

( RealAudio and RealVideo software)( RealAudio and RealVideo software)

MPEGMPEG

Standard developed by the Moving PIcturesExperts Group Standard developed by the Moving PIcturesExperts Group for digital representation of moving pictures and for digital representation of moving pictures and associated audioassociated audio

http://mpeg.org

Digital Video CompressionDigital Video Compression

MPEG is a real-time video compression algorithm. MPEG is a real-time video compression algorithm. ((MMoving oving PPicture icture EExperts xperts GGroup)roup)

MPEG-4 (1998-1999) includes numerous multimedia MPEG-4 (1998-1999) includes numerous multimedia capabilities and is a preferred standard.capabilities and is a preferred standard.

MPEG-7 (2002) (or Multimedia Content Description MPEG-7 (2002) (or Multimedia Content Description Interface) integrates information about motion video Interface) integrates information about motion video elements with their use.elements with their use.

MPEG –21 under developmentMPEG –21 under development

Digital VideoDigital Video

Video clips can be shot or converted to digital format and Video clips can be shot or converted to digital format and stored on the hard drive. stored on the hard drive.

They can be played back without overlay boards, second They can be played back without overlay boards, second monitors or videodiscs using QuickTime or Active Movie monitors or videodiscs using QuickTime or Active Movie for Windowsfor Windows

Analog video can be converted to digital or now created in Analog video can be converted to digital or now created in digital formdigital form

Video Recording and Tape Video Recording and Tape FormatsFormats

Composite analog video.Composite analog video. Component analog video.Component analog video. Composite digital.Composite digital. Component digital.Component digital. ATSC digital TV.ATSC digital TV.

Composite Analog VideoComposite Analog Video

CompositeComposite video video combinescombines the luminance and chroma the luminance and chroma information from the video signal.information from the video signal.

Composite video produces lowest quality video and is most Composite video produces lowest quality video and is most susceptible to generation loss.susceptible to generation loss.

Generation loss is the loss of quality that occurs while Generation loss is the loss of quality that occurs while moving from original footage to editing master to copy.moving from original footage to editing master to copy.

Component Analog VideoComponent Analog Video

ComponentComponent video video separatesseparates the luminance and chroma the luminance and chroma information.information.

It improves the quality of the video and decreases It improves the quality of the video and decreases generation loss.generation loss.

In S-video, color and luminance information are kept on In S-video, color and luminance information are kept on two separate tracks (Y/C) to improve the picture quality.two separate tracks (Y/C) to improve the picture quality.

Betacam is a new portable professional video format which Betacam is a new portable professional video format which lays the signal on the tape in three component channels.lays the signal on the tape in three component channels.

Composite DigitalComposite Digital

CompositeComposite digital recording formats digital recording formats combinecombine the the luminance and chroma information.luminance and chroma information.

They sample the incoming waveforms and encode the They sample the incoming waveforms and encode the information in binary (0/1) digital code.information in binary (0/1) digital code.

It improves color and image resolution and eliminates It improves color and image resolution and eliminates generation loss.generation loss.

Component Digital Component Digital

Component digital formats add the advantages of Component digital formats add the advantages of component signals to digital recording.component signals to digital recording.

D-1 component digital format is an uncompressed D-1 component digital format is an uncompressed format which has a very high quality image.format which has a very high quality image.

It uses a 19 mm (3/4-inch) tape in order to save data.It uses a 19 mm (3/4-inch) tape in order to save data. Several other digital component formats are DCT, Several other digital component formats are DCT,

Digital Betacam, DV format, DVCPRO, and DVCAM Digital Betacam, DV format, DVCPRO, and DVCAM formats.formats.

ATSC Digital TVATSC Digital TV

These standards provide for digital STV and HDTV These standards provide for digital STV and HDTV recordings that can be broadcast by digital TV recordings that can be broadcast by digital TV transmitters to digital TV receivers.transmitters to digital TV receivers.

ATSC standards also provide for enhanced TV bringing ATSC standards also provide for enhanced TV bringing the interactivity of multimedia and the Web to broadcast the interactivity of multimedia and the Web to broadcast television. television.

Vaughn’s Law of Multimedia Vaughn’s Law of Multimedia MinimumsMinimums

Your goal is to produce multimedia that is adequate and Your goal is to produce multimedia that is adequate and does it’s job but doesn’t throw you into bankruptcy.does it’s job but doesn’t throw you into bankruptcy.

Experiment with various levels of consumer grade Experiment with various levels of consumer grade equipmentequipment

Professional sound and video equipment is very expensiveProfessional sound and video equipment is very expensive

Recording FormatsRecording Formats

S-VHS and Hi-8 consumer qualityS-VHS and Hi-8 consumer quality Component (YUV) - Sony BetacamSP the professional Component (YUV) - Sony BetacamSP the professional

standard for broadcast qualitystandard for broadcast quality Component Digital- a digital version of the Betacam- Component Digital- a digital version of the Betacam-

best format for best format for graphics > $900,000 and produces 15 minutes of videographics > $900,000 and produces 15 minutes of video Composite Digital most common >$110,000Composite Digital most common >$110,000

Shooting and Editing VideoShooting and Editing Video

Shooting platformShooting platform• use a steady tripoduse a steady tripod

• or a camera with an electronic image stabilization feature to avoid or a camera with an electronic image stabilization feature to avoid “shaky hand effect”“shaky hand effect”

• or use camera moves and moving subjects to disguise your lack of or use camera moves and moving subjects to disguise your lack of steadinesssteadiness


Lighting performance is the main difference between Lighting performance is the main difference between professional and consumer camcordersprofessional and consumer camcorders

Use a simple floodlight kit or natural daylight to improve Use a simple floodlight kit or natural daylight to improve the imagethe image

Onboard flood lights can be used as fill light to illumine Onboard flood lights can be used as fill light to illumine facesfaces



Chroma Key or Blue Screen - popular technique for Chroma Key or Blue Screen - popular technique for making multimedia without the use of expensive making multimedia without the use of expensive backgroundsbackgrounds

In shooting against a blue screen, be sure that the lighting In shooting against a blue screen, be sure that the lighting is perfectly even and that actors are not too close to the is perfectly even and that actors are not too close to the screen so that color “spills” over on themscreen so that color “spills” over on them


CompositionComposition• Avoid wide panoramic shotsAvoid wide panoramic shots

• Use close-ups, head and shouldersUse close-ups, head and shoulders

• Remember the more a scene changes the slower the playback will Remember the more a scene changes the slower the playback will bebe

• Keep the camera still, let the subject add the motion by walking, Keep the camera still, let the subject add the motion by walking, turning...turning...

Using Video TapesUsing Video Tapes

Fast forward new tapes and rewind them so that the Fast forward new tapes and rewind them so that the tension is even (called “packing”)tension is even (called “packing”)

Black-stripe the tape by running it through the recorder Black-stripe the tape by running it through the recorder with the lens cap on -eliminates “snowy noise”with the lens cap on -eliminates “snowy noise”

Do not reuse tapes after editingDo not reuse tapes after editing Remove break off tab to avoid overwritingRemove break off tab to avoid overwriting

Video Hardware ResolutionVideo Hardware Resolution

Horizontal resolution -the number of lines of detail the Horizontal resolution -the number of lines of detail the camera can reproducecamera can reproduce

Different from the vertical scan lines on TVDifferent from the vertical scan lines on TV The lens, and number, size and quality of the CCDs The lens, and number, size and quality of the CCDs

determine the resolution determine the resolution Poor resolution = poor image Poor resolution = poor image

Consumer Grade EquipmentConsumer Grade Equipment

Mass production at low cost; easier to useMass production at low cost; easier to use Cameras and camcorders that use HI-8 and S-VHS Cameras and camcorders that use HI-8 and S-VHS

formats are superior to 8 mm and VHS systemsformats are superior to 8 mm and VHS systems HI-8 is most widely available tape format and best HI-8 is most widely available tape format and best

consumer gradeconsumer grade

Making Tape CopiesMaking Tape Copies

For demo or promo tapes use at least Super VHS ( HI-8 is For demo or promo tapes use at least Super VHS ( HI-8 is best and allow unlimited copies to be made without best and allow unlimited copies to be made without degradation)degradation)

Copying ( dubbing) depends on the tape format and the Copying ( dubbing) depends on the tape format and the quality of the equipment being usedquality of the equipment being used

Copy in SP mode- faster writing produces better imagesCopy in SP mode- faster writing produces better images

Video Window SizeVideo Window Size

Shrinking a digitized image improves it perceived Shrinking a digitized image improves it perceived sharpnesssharpness

( Also happens when you switch from 19” to 13” TV)( Also happens when you switch from 19” to 13” TV) The image is crisper because the scan lines are closer The image is crisper because the scan lines are closer

togethertogether

Editing with Consumer VCRsEditing with Consumer VCRs

Editing with 2 VCRs causes problems because the two Editing with 2 VCRs causes problems because the two machines are not in syncmachines are not in sync

Editing software, such as Premier, or After Effects, has Editing software, such as Premier, or After Effects, has become more commonly used in multimediabecome more commonly used in multimedia

P*64P*64

Video telephone conferencing standard for compressing Video telephone conferencing standard for compressing audio and motion video imagesaudio and motion video images

Encodes audio and video for transmission over copper or Encodes audio and video for transmission over copper or fiber optic linesfiber optic lines

Other compression systems are currently being developed Other compression systems are currently being developed by Kodak, Sony, etc.by Kodak, Sony, etc.

Optimizing Video files for CD-ROMsOptimizing Video files for CD-ROMs

CD- ROMs are an excellent distribution media for CD- ROMs are an excellent distribution media for multimedia: inexpensive, store great quantities of multimedia: inexpensive, store great quantities of information, with adequate video transfer ratesinformation, with adequate video transfer rates

Suitable for QuickTime and AVI file formats as well as Suitable for QuickTime and AVI file formats as well as those produced by Director, etc.those produced by Director, etc.

Optimizing Video files for CD-Optimizing Video files for CD-ROMsROMs

Limit the synchronization between video and audioLimit the synchronization between video and audio• AVI interleaves themAVI interleaves them• QuickTime files must be “flattened” - to interleave the audio QuickTime files must be “flattened” - to interleave the audio

and videoand video Use regularly spaced key frames (10 to 15 frames apart)Use regularly spaced key frames (10 to 15 frames apart) Limit the size of the video window- the more data the Limit the size of the video window- the more data the

slower the playbackslower the playback

Optimizing Video files for CD-Optimizing Video files for CD-ROMsROMs

Choose the software compression algorithm carefullyChoose the software compression algorithm carefully• Sorenson codec is optimized for CD-ROM playbackSorenson codec is optimized for CD-ROM playback• Cinepack algorithm, available with AVI and QuickTime, is also Cinepack algorithm, available with AVI and QuickTime, is also

optimized for CD-ROM playbackoptimized for CD-ROM playback• Use Norton speed Disk to defragment your files before burning the Use Norton speed Disk to defragment your files before burning the

mastermaster

SummarySummary

Various video standards are NTSC, PAL, SECAM, and Various video standards are NTSC, PAL, SECAM, and ATSC DTV.ATSC DTV.

Categories of video standards are composite analog, Categories of video standards are composite analog, component analog, composite digital, and component component analog, composite digital, and component digital.digital.

Documents

Video. Overview b Using video. b How video works? b Broadcast video standards. b Analog video. b Digital video. b Video recording and tape formats. b