TV Tech Basics for Non-Linear Editors GVExpo 2006 Eric Wenocur Lab Tech Systems Silver Spring, MD [email protected] Eric Wenocur Lab Tech Systems

TV Tech Basics forNon-Linear Editors

GVExpo 2006

TV Tech Basics forNon-Linear Editors

GVExpo 2006

Eric Wenocur

Lab Tech Systems

Silver Spring, MD

[email protected]

Eric Wenocur

Lab Tech Systems

Silver Spring, MD

[email protected]

2

Tutorial OverviewTutorial Overview

Elements of a Non-Linear Editing System

Monitors, Scopes and Video

Mixers and Audio

Videotape Machines

Simple Troubleshooting

Elements of a Non-Linear Editing System

Monitors, Scopes and Video

Mixers and Audio

Videotape Machines

Simple Troubleshooting

3

NLEVTR Storage

Mixer

SpeakersVideo Mon & Scopes

Typical NLE SystemTypical NLE System

4

System Engineering PerspectiveSystem Engineering Perspective

Maintain Signal Quality

Accurate Monitoring What is the signal really like?

How will it look/sound elsewhere?

Flexibility

Maintain Signal Quality

Accurate Monitoring What is the signal really like?

How will it look/sound elsewhere?

Flexibility

5

Monitors, Scopes & VideoMonitors, Scopes & Video

Top Four Mistakes or Misconceptions

6



1) Adjusting the monitor to make the picture look “right”

7




2) Lack of colorbars at head of tape or sequence

8





3) Program not referenced to Bars

9





4) Incorrect levels and other errors in the picture

3) Program not referenced to Bars

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Why Bars & Tone Matter!Why Bars & Tone Matter!

How does anyone know what

YOUR show is supposed to look like?

And furthermore…

How does anyone know what

ANYTHING is supposed to look like?

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Why Bars & Tone Matter!Why Bars & Tone Matter!

We know what colorbars are supposed to look like(they have been defined by Standards).

Establish a known reference for Content(which includes the conditions at the time)

Use for setting up tape playback toproduce the desired result

Useful for verifying proper operation of equipment and systems

We know what colorbars are supposed to look like(they have been defined by Standards).

Establish a known reference for Content(which includes the conditions at the time)

Use for setting up tape playback toproduce the desired result

Useful for verifying proper operation of equipment and systems

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The Monitor as a ToolThe Monitor as a Tool

Apply a known good signal

Set up the monitor

Leave it alone!

Apply a known good signal

Set up the monitor

Leave it alone!

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Simple Monitor SetupSimple Monitor Setup

Use known correct SMPTE Bars (composite)

Set desired ambient light

Set controls back to Presets

Adjust brightness (black level) for correct Pluge

Adjust chroma and phase in “blue gun” mode

Set contrast for moderate intensity

Use known correct SMPTE Bars (composite)

Set desired ambient light

Set controls back to Presets

Adjust brightness (black level) for correct Pluge

Adjust chroma and phase in “blue gun” mode

Set contrast for moderate intensity

14

Where to get test signals?Where to get test signals?

Facility test generator

Non-linear editor

Many newer VTRs

Professional cameras

Facility test generator

Non-linear editor

Many newer VTRs

Professional cameras

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Other Monitor ControlsOther Monitor Controls

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So…So…

How do we know if the

TEST SIGNAL is good?

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Waveform Monitor/VectorscopeConventional & Rasterizing

Waveform Monitor/VectorscopeConventional & Rasterizing

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Waveform Monitor & Vectorscope

Waveform Monitor & Vectorscope

Measure luminance and chrominance levels

Find appropriate black or white levels,appropriate saturation, check hue

Display color-balance information(for color-correction)

Find flaws in video, track downsystem problems

Measure luminance and chrominance levels

Find appropriate black or white levels,appropriate saturation, check hue

Display color-balance information(for color-correction)

Find flaws in video, track downsystem problems

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Waveform MonitorWaveform Monitor

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VectorscopeVectorscope

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Recommended LevelsRecommended Levels

Keep luma between 7.5 and 105 ire

Keep chroma between -20 and 100 ire

Rules are most stringent for conventionalbroadcasting and anything on satellite

Use common sense…

Keep luma between 7.5 and 105 ire

Keep chroma between -20 and 100 ire

Rules are most stringent for conventionalbroadcasting and anything on satellite

Use common sense…

Using composite scopes…

22

Typical NLE Video Signal PathTypical NLE Video Signal Path

NLEVTR

Signals could be composite, Y/Ccomponent, SDI…

23

Video Signal FormatsVideo Signal Formats“F” Cable:

RF (cable TV)“F” Cable:

RF (cable TV)

RGB Set:Component Analog

RGB Set:Component Analog

BNC Cable:Analog & Digital

Video

BNC Cable:Analog & Digital

Video

Y/C Cable:S-Video

Y/C Cable:S-Video

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Critical Video Connection RulesCritical Video Connection Rules

Video signal lines must terminatein 75-ohms at the end of the run!

You cannot passively “split” or “combine”video signals!

You can passively “loop” signals betweendevices, but must terminate at end!

Video signal lines must terminatein 75-ohms at the end of the run!

You cannot passively “split” or “combine”video signals!

You can passively “loop” signals betweendevices, but must terminate at end!

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Possible NLE Video Signal PathPossible NLE Video Signal Path

NLEVTR

Note: VTR signal loops through monitor

Mon

A B

Term

26

Typical Monitor Rear ViewTypical Monitor Rear View

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Some CommonVideo System Problems

Some CommonVideo System Problems

No termination or double-termination(watch those switches and terminators)

Two signals feeding same input(improperly using passive loop-thrus)

Component cable mixup (Y, R-Y, B-Y)

Component mode error (YRB vs. RGB)

No termination or double-termination(watch those switches and terminators)

Two signals feeding same input(improperly using passive loop-thrus)

Component cable mixup (Y, R-Y, B-Y)

Component mode error (YRB vs. RGB)

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Video UnterminatedVideo Unterminated

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Video Double-terminatedVideo Double-terminated

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Component Cable MixupComponent Cable Mixup

CorrectCorrect R-Y & B-Y SwappedR-Y & B-Y Swapped

31

A few words aboutReference, Genlock and Timing

A few words aboutReference, Genlock and Timing

Reference signals are used to make equipmentproduce output signals in sync with each other.

Reference is about playback, not recording;the recording device always locks to its input signal.

To “genlock” means locking a device to a reference signal.

“Timing” is about the relationship between two devices that both feed a third device (such as cameras feedinga switcher).

There is NO “timing” in a standalone NLE system!

Having devices locked to a common reference is highlyrecommended, but not critical in most cases.

Reference signals are used to make equipmentproduce output signals in sync with each other.

Reference is about playback, not recording;the recording device always locks to its input signal.

To “genlock” means locking a device to a reference signal.

“Timing” is about the relationship between two devices that both feed a third device (such as cameras feedinga switcher).

There is NO “timing” in a standalone NLE system!

Having devices locked to a common reference is highlyrecommended, but not critical in most cases.

32

Mixers & AudioMixers & Audio

Top Three Mistakes or Misconceptions

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1) Incorrect signal levels between equipment

34




2) Monitoring incorrect or mixed-up signals

35




2) Monitoring incorrect or mixed-up signals

3) Distortion and other problems in audio

36

Basic Mixer SectionsBasic Mixer Sections

Input ChannelsProcess signals entering mixer(input jacks, mic preamp, equalizer, channel fader)

Buses & OutputsCombine signals together and send out(bus assign, bus master level, output jacks)

MonitoringControls speaker volume and what is heard(mon source select, speaker select, speaker volume)

Input ChannelsProcess signals entering mixer(input jacks, mic preamp, equalizer, channel fader)

Buses & OutputsCombine signals together and send out(bus assign, bus master level, output jacks)

MonitoringControls speaker volume and what is heard(mon source select, speaker select, speaker volume)

37

Basic Mixer SectionsBasic Mixer Sections

Monitor

Section

Output Bus

Masters

Aux Bus

Masters&

Misc.

Input Channel Strips

38

Mixer Flow #1Input Channels

BusesOutputs

Mixer Flow #1Input Channels

BusesOutputs

39

Mixer Flow #2Input Channel

Aux Send with Pre/Post SelectBuses & Outputs

Mixer Flow #2Input Channel

Aux Send with Pre/Post SelectBuses & Outputs

40

Mixer Flow #3

Added MonitorSection

Mixer Flow #3

Added MonitorSection

41

Issues with Audio ConnectorsIssues with Audio Connectors

The same types of connectors are often usedfor different types of signals(eg: XLRs for both mic and line level).

Some connectors look similar but aren’t(eg: 2- and 3-conductor phone plugs).

Preponderance of unbalanced “consumer” connectors (RCA phono plug) on gear.

The same types of connectors are often usedfor different types of signals(eg: XLRs for both mic and line level).

Some connectors look similar but aren’t(eg: 2- and 3-conductor phone plugs).

Preponderance of unbalanced “consumer” connectors (RCA phono plug) on gear.

42

Common Audio ConnectorsCommon Audio Connectors

Phone plugsPhone plugs

Terminal Block

Terminal Block

XLR plugsXLR plugs

RCA plugRCA plugMini plugMini plug

43

Audio Operating LevelAudio Operating Level There are roughly three categories of audio operating level:

Mic, Line and Speaker.

“Line” has a wide range of levels in usebetween equipment.

Professional equipment line levels are typically10-20 dB higher than consumer or “prosumer”.

Pro level is often referred to as “+4”Consumer level is often known as “-10”

It is not wise to connect these devices together without proper interfacing to compensate!

There are roughly three categories of audio operating level: Mic, Line and Speaker.

“Line” has a wide range of levels in usebetween equipment.

Professional equipment line levels are typically10-20 dB higher than consumer or “prosumer”.

Pro level is often referred to as “+4”Consumer level is often known as “-10”

It is not wise to connect these devices together without proper interfacing to compensate!

44

Connectors & Signals ChartConnectors & Signals Chart

45

Typical Mixer ConnectionsTypical Mixer Connections

Aux Sends

SubBusOuts

TapeIns/Outs

MainBusOuts

CRMonOuts

Input Channels

Channel InsertLine Input

Mic Input

46

A Word about Phantom PowerA Word about Phantom Power

48 volts DC used to power condensor microphones

This voltage can damage other equipment.

Unless you are using a condensor micLEAVE IT OFF!

48 volts DC used to power condensor microphones

This voltage can damage other equipment.

Unless you are using a condensor micLEAVE IT OFF!

47

Possible NLE Audio Signal PathPossible NLE Audio Signal Path

NLEVTR

Mixer

Input Channels

Output Buses

Monitoring

48

VTR to Mixer to NLEVTR to Mixer to NLE

NLEVTR

Mixer

Input Channels

Output Buses

Monitoring

49

NLE to Mixer to VTRNLE to Mixer to VTR

NLEVTR

Mixer

Input Channels

Output Buses

Monitoring

50

Possible NLE Audio Signal PathPossible NLE Audio Signal Path

NLEVTR

Mixer

Input Channels

Output Buses

Monitoring

51

Interfacing Consumer GearInterfacing Consumer Gear

VHS

Mixer

Input Channels

Output Buses

Monitoring

Use TAPE Outsto feed VHS or DVD-R

(same signal as Main Outs but correct level)

52

Audio MeteringAudio Metering

Why does the same audio

look different

on

different meters?

Why does the same audio

look different

on

different meters?

53

Uh oh…Uh oh…

54

Audio MeteringAudio Metering

Mechanical analog or bargraph?

Where is “0”? Different for analog and digital applications.

How large is the scale range? Meters vary from 23dB to 60 or 80dB scales.

How quickly does the meter respond to changes in audio? Ballistics can be average, peak, PPM, etc.

Mechanical analog or bargraph?

Where is “0”? Different for analog and digital applications.

How large is the scale range? Meters vary from 23dB to 60 or 80dB scales.

How quickly does the meter respond to changes in audio? Ballistics can be average, peak, PPM, etc.

55

Audio Metering AnalogAudio Metering Analog

Analog audio will distort when level is too high, but the effect is usually gradual.

Analog meters were designed to show average levels around 0VU.

There is usually 10-20 dB left above 0VU before distortion.

Tone should be at 0VU.

Analog audio will distort when level is too high, but the effect is usually gradual.

Analog meters were designed to show average levels around 0VU.

There is usually 10-20 dB left above 0VU before distortion.

Tone should be at 0VU.

56

Audio Metering DigitalAudio Metering Digital

Digital audio has an absolute upper limitwhich is called Full Scale.

Digital meters read in terms of dBFS (decibels under Full Scale)

Maximum possible level is at 0 dBFS.

Tone is usually at about -20 dBFS so there is 20dB of headroom before overload.

Digital audio has an absolute upper limitwhich is called Full Scale.

Digital meters read in terms of dBFS (decibels under Full Scale)

Maximum possible level is at 0 dBFS.

Tone is usually at about -20 dBFS so there is 20dB of headroom before overload.

57

Typical Audio FlawsTypical Audio Flaws

Clipping and other distortion

Excessive noise beneath audio

Tonal imbalance

Channel phase reversal

Audio/video lip-sync errors

Clipping and other distortion

Excessive noise beneath audio

Tonal imbalance

Channel phase reversal

Audio/video lip-sync errors

58

Balanced andUnbalanced Connections

Balanced andUnbalanced Connections

This has nothing to do with “sonic balance.”

Balanced audio connections cancel out noise picked up on the cable.

Balanced typically uses two signal wires and a shield, connectors have three terminals.

Balanced is usually also “pro” (+4) level.

You can connect balanced and unbalanced together but it requires knowledge!

This has nothing to do with “sonic balance.”

Balanced audio connections cancel out noise picked up on the cable.

Balanced typically uses two signal wires and a shield, connectors have three terminals.

Balanced is usually also “pro” (+4) level.

You can connect balanced and unbalanced together but it requires knowledge!

59

Videotape MachinesVideotape Machines


60



1) Wrong format / wrong deck

61




2) Failure to begin with controls in PRESET

62





3) Failure to set up playback to Bars

63





3) Failure to set up playback to Bars

4) Screwing with menus and switches

64

Videotape FormatsVideotape Formats

Legacy Analog:

VHS, S-VHS, Hi-8

3/4” (U-matic), 1”

Betacam, Beta SP

Legacy Analog:

VHS, S-VHS, Hi-8

3/4” (U-matic), 1”

Betacam, Beta SP

65


Legacy Digital:

D-1, D-3 (component)

D-2 (composite)

Legacy Digital:

D-1, D-3 (component)

D-2 (composite)

66


Digital Betacam Family:

Digi Beta

Betacam SX

Betacam IMX

Digital Betacam Family:

Digi Beta

Betacam SX

Betacam IMX

67


Other Current Digital:

D-5

D-9 (Digital-S)

Other Current Digital:

D-5

D-9 (Digital-S)

68


DV-based:

DV, mini-DV

DVCam

DVCPro 25/50/100

DV-based:

DV, mini-DV

DVCam

DVCPro 25/50/100

69

PVW-2800 Internal ViewPVW-2800 Internal View

Cassette ElevatorCassette Elevator

Video & AudioCircuit BoardsVideo & AudioCircuit Boards

Control & Misc.Circuit Boards

Control & Misc.Circuit Boards

Video Head DrumVideo Head Drum

Audio HeadsAudio Heads

CapstanCapstan

Threading MotorThreading Motor

70

VTR SystemsVTR Systems

Video processing

Audio processing

Capstan servo -- controls tape movement

Drum servo -- controls head drum

Video processing

Audio processing

Capstan servo -- controls tape movement

Drum servo -- controls head drum

71

VTR ServosVTR Servos

Lock to Reference input during playback

Lock to Record input during recording

Internal TBC (timebase corrector) may lock differently than servo system

Lock to Reference input during playback

Lock to Record input during recording

Internal TBC (timebase corrector) may lock differently than servo system

72

VTR Tape TracksVTR Tape Tracks

Longitudinal Audio TracksLongitudinal Audio Tracks

Longitudinal Control TrackLongitudinal Control Track

Helical Video TracksHelical Video Tracks

Longitudinal TC TrackLongitudinal TC Track

Similar for analog or digital formatsSimilar for analog or digital formats

73

VTR Recording ModesVTR Recording Modes

E/E (electronics-to-electronics) -- passes input signals through to output

Hard (crash) Record -- erases and records all tracks at once, no sync with previous recording

Assemble Record -- erases and records all tracks, but picks up in sync with previous recording

Insert Record -- only erases and records selected tracks (control track must be present!)

E/E (electronics-to-electronics) -- passes input signals through to output

Hard (crash) Record -- erases and records all tracks at once, no sync with previous recording

Assemble Record -- erases and records all tracks, but picks up in sync with previous recording

Insert Record -- only erases and records selected tracks (control track must be present!)

74

VTR Front PanelVTR Front Panel

Audio Level Controls& Meters Transport

Controls

Editing Controls

Remote Select

Timecode Display & Menus

Timecode Controls may be various places!

75

VTR Rear Panel ConnectorsVTR Rear Panel ConnectorsAnalog Audio I/O

d

dd

d

d

Analog VideoInputs

Analog VideoOuputs

Remote ControlAnd Misc.

Digital AudioI/O

Digital VideoI/O

76

Menus & Special SwitchesMenus & Special Switches

Ref Auto/Manual: Set to AUTO

Audio input 600-ohm terminations: Set to OFF

Audio input level: Set to HIGH

Ref Auto/Manual: Set to AUTO

Audio input 600-ohm terminations: Set to OFF

Audio input level: Set to HIGH

If your VTR has any of the followingswitches on the back…

If your VTR has any of the followingswitches on the back…

77

Menus & Special SwitchesMenus & Special Switches

When in doubtuse the Factory Default settings!

When in doubtuse the Factory Default settings!

78

Simple TroubleshootingSimple Troubleshooting

Use good observation techniques:

Note all conditions during problem

Note conditions leading up to problem

When was the last good operation?What changed?

Be clear about meaning of words!

Use good observation techniques:

Note all conditions during problem

Note conditions leading up to problem

When was the last good operation?What changed?

Be clear about meaning of words!

79

Troubleshooting StrategiesTroubleshooting Strategies

It pays to know how things are SUPPOSED to work.

Start with known good signals (bars and tone), good path and monitoring.

Change one thing and observe…

Swap things: cables, equipment, software

Cut problem in half

It pays to know how things are SUPPOSED to work.

Start with known good signals (bars and tone), good path and monitoring.

Change one thing and observe…

Swap things: cables, equipment, software

Cut problem in half

80

Troubleshooting StrategiesTroubleshooting Strategies

Manuals are like GOLD!Manuals are like GOLD!

81

Are you a professional?Are you a professional?

Please send me feedbackon this workshop!

And visit the SMPTE boothon the exhibit floor!

Please send me feedbackon this workshop!

And visit the SMPTE boothon the exhibit floor!

Eric Wenocur

Lab Tech Systems

Silver Spring, MD

[email protected]

Eric Wenocur

Lab Tech Systems

Silver Spring, MD

[email protected]

Copyright 2006 Eric WenocurAll photos copyright their respective owners.

Copyright 2006 Eric WenocurAll photos copyright their respective owners.

Documents

TV Tech Basics for Non-Linear Editors GVExpo 2006 Eric Wenocur Lab Tech Systems Silver Spring, MD [email protected] Eric Wenocur Lab Tech Systems