Troubleshooting HD Video Throughout Broadcast Chain

2/17/20101

Troubleshooting HD Video Throughout Broadcast Chain

Karl KuhnSr. Video Application [email protected]

2/17/20102 =22

Television Signal Formats--- Tektronix

Matrix

CompositeEncoder

A to DConv

Serializer

R

G

B

270MHz

Y

R-Y

B-Y

6.75MHz Sample

Rate for B-Yand R-Y

13.5MHzSample

Rate for Y

Serializer

Clock X10

ITU-R BT.601-2Serial DigitalComponent270Mb/sec

YR-YB-Y

10 Bits Parallel

ITU-R BT.601-2Parallel Digital Component27MB/sec

Serial Digital Composite143Mb/sec (NTSC)177Mb/sec (PAL)

Parallel Digital CompositePAL=17.7MHz

NTSC=14.3MHz

Multiplexed 27MB/secB-Y/Y/R-Y/Y/B-Y/Y

10 Bits Parallel

4Fsc(PAL=17.7MHz)

(NTSC=14.3MHz)

ComponentAnalog Video

(RGB)

Analog CompositeVideo(PAL/NTSC)

MPEG2ProgramEncoder

DVDDigital Versatile

(Video) Disk

A to DConv

Audio

Color DifferenceComponentAnalog Video(Y, B-Y, R-Y)

MPEG2 Protocol

Transport StreamTransmission

Channel

Tx

TransmissionChannel

RxMPEG2ProgramDecoder

MPEG2 Protocol

Transport Stream

Transmission Channel Analysis

GigE and/or Modulated RF Signals.

MPEG2 Protocol Analysis

PictureQuality

Analysis

SD and HD Digital Video

MPEG2 Protocol

Program Stream

Data

Data

Analog CompositeVideo (PAL/NTSC)

A to DConv

A to DConv

2/17/20103

Basic Anatomy of the human vision system

http://webvision.med.utah.edu/index.html

3 Color and Gamut Monitoring

� Physical part/elements– Eye, Lens and Retina

– Rods – Sensitive to Blue-green light

– Used for vision under dark-dim

conditions.

– Cones – 3 Types of Cones

Sensitive to either

long wavelengths of light (red light)

medium wavelengths of light (green light)

short wavelengths of light (blue light) – Optic nerve

2/17/20104 Tektronix Video Insight Seminar Series4

Technology evolutionNTSC Composite

BlankingLevel 0V,0 IRE

PeakWhite100 IRE

Horizontal Sync Pulse Color Burst

Horizontal Blanking Interval

Active Picture

Setup,Ref

Black7.5 IRE


Picture Observation of the Digital Cliff

Digital signals are efficient, versatile and provide excellent quality.

Digital signals have strong noise tolerance…

But, be aware of the Digital Cliff

Please

Standby

2/17/201066

� Analog

– Degrades Gracefully

– Window into Electronic World

– You Decide

� Digital

– Cliff Effect

– Can’t See Ones and Zeros

– The Technology Decides for You

� Intensive Care Ward

� Big Circuit Board

� Need Right Tools

� Figure Pointing

� Never Any Funding

Analog vs. Digital

6


SMPTE 292 Digital Horizontal Line

First active picture sampleLast active picture sample

COMPONENT: Active line digitized, EAV/SAV added

EA

V

SA

V

3F

F3

FF

00

000

0

00

000

0

XY

Z

XY

Z

0C

b

1Y

2C

r

3Y

3F

F C

3F

F Y

000

C

000

Y

00

0

C00

0

Y

XY

Z C

XY

Z Y

LN

0 C

LN

0 Y

LN

1 C

LN

1 Y

CR

C0

YC

R0

CR

C1

YC

R1

XYZ Word Conveys Start/End of Line (H),Vertical Blanking (V), and Field (F)

Analog Tri-level Sync

0mV

-300mV

+300mV


Chromaticity

• Formats limit color range

• Care has to be taken when converting between formats


Technology evolutionDigital Component

M

A

T

R

I

XDigitize

At this

point


Component Waveform Overlay Mode

700

Tek

0

No IRE scale

it’s now a mV

scale 700mV

is now Peek

white.

No Reference

Black at 7.5

IRE,

Reference

Black is now

at 0mV

No Sync

Pulse as

such, it’s now

a Data word.

2/17/20101111

Gamut Monitoring — the traditional way

100% Bars

Y, Pr, Pb

White Gamut

Black

Gamut


Component Color Difference

10-bit Quantizing

Excluded 399.2 mV 3FF 11 1111 1111

Max Positive 350.0 mV 3C0 11 1100 0000

Black 0.0 mV 200 10 0000 0000

Max Negative -350.0 mV 040 00 0100 0000

Excluded -400.0 mV 000 00 0000 0000

Pr Channel Pb Channel


Impact of Distortions on Different Color Spaces

A signal can be legal in one color space but not valid when converted to another

Legal RGB

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

A

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

Converted back toRGB

D Illegal

Converted to LegalColor Difference

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

B

DistortedColor Difference

Legal

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

C

2/17/20101414

Gamut Monitoring RGB — Diamond display

RGBGamut

Configuration MenuSelectable Gamut Thresholds

2/17/20101515

Gamut Monitoring Composite — Arrowhead display

ChromaGamut

LumaGamut

Configuration MenuSelectable Gamut Thresholds

2/17/20101616

Transmission – Using the Arrowhead display

� Used with both live and test

signals

� Adjustable Alarm limits

� Can be used with SD and HD

content to determine Composite

legality

2/17/201017

New Spearhead Display (Color Lightness, Saturation and Value)

X(i) = max(i) - min(i)

Y(i) = [max(i) + min(i)]/2

50%

75%

25%

100%

75%

50%

25%

Value

Saturation (HSV)

Lightness

black

white

monochrome axis

50%

100%

25%

102% (limit)

0%

- 0.5%

105%

Spearhead triangular RGB Gamut space:

max(i) = maximum of r(i), g(i) , b(i);

min(i) = minimum of r(i), g(i) , b(i);

in mV.

The space is bounded by 3 lines:

1) the vertical line (monochrome) where

max(i) = min(i),

i.e. Y(i) = max(i) = min(i), X(i) = 0;

2) the line of all possible 100% Saturated

colors where min(i) = 0, max(i) = 0..700mV

i.e Y(i) = max(i)/2, X(i) = max(i),

or graphically the y = x/2 line;

and

3) the line of all possible 100% Value colors

where max(i) = 700mV, min(i) = 0..700mV

i.e Y(i) = 700mV/2 + min(i)/2,

X(i) = 700mV - min(i),

or graphically the y = -x/2 + 700mV

Note: All valid rgb values (r(i), g(i), or b(i)

within the range 0.. 700mV) are contained

within the Spearhead triangular gamut

space. All invalid (or illegal) rgb values

(min(i) < 0, or max(i) > 700mV) are outside

the Spearhead gamut space. Adjustable

gamut limit detector thresholds are indicated

as graticule markers (i.e. -0.5% and 105%).

2/17/201018

Constant Hue Test Pattern with combinations of Saturation and Value in 25% intervals

2/17/201019

Rainbow Pattern with Color Corrector Green Gamma Adjustment Error


Timing Measurement – Using Lightning display

� Bowing indicates a timing error

4 Direction shows advance or delay

4 Location shows which component is at fault

4 Crosshairs quantify


Construction of Lightning display

2/17/20102222

Color Error Shown Crosshatched

YellowError


Good Y Pb Pr & RGB but Bad NTSC


Color Error Shown Crosshatched

YellowError


Color Error Corrected


Checking Format Conversion

HD

Content

SD

Content

2/17/20102727

Video Session

� Shows SDI input

� Signal format

� SMPTE 352 Payload ID (more on this later)

� SAV Placement Errors

� Field Length Errors

� Line Length Errors

� Line Number Errors

� Stuck Bits

� CRC Checksum Errors

– Error Sec, # of Error Fields

% Error Fields


CRC Process, (EDH)

Standard Definition 270Mb/s

High Definition1.485 Gb/s even rates(1.485/1.001) = 1.4835 Gb/s odd rates


UnitInterval

0.8 Volts+ 10%

Jitter0.2 UI p-pAlignment

OrTiming

20% to 80%Risetime

0.4 to 1.5 nsshall not differ by more than .5 ns

SD Serial Digital Waveform

One Clock Interval 3.7ns

+/-10%Overshoot/Undershoot


UnitInterval

0.8 Volts+ 10%

20% to 80%Risetime

< 270psshall not differ by more than 100 ps

HD Serial Digital Waveform


Jitter0.2 UI p-pAlignment1.0 UI p-p

Timing

One Clock Interval 673ps


HD Eye Measurement

80%

20%

AmplitudeAmplitude

Rise Time

Rise Time

Fall Time

Fall Time

Auto MeasureAuto Measure


Eye Specifications Summary

Rise/Fall Time

SD HD 3Gb/s

Shall be no less than 0.4ns, no

greater than 1.50ns,

and shall not differ

by more than 0.5ns

Shall be no greater than 270ps and

shall not differ by more than 100ps

Shall be no greater than 135ps and

shall not differ by more than 50ps

Unit Interval

SD (259M)

HD (292M)

3Gb/s (424M)

3.7ns 673.4ps 336.7ps

UnitInterval

0.8 Volts+ 10%

Jitter 20% to 80%Risetime



The variation in position of a signal’s

transitions relative to those of a clock

extracted from the signal.

The variation in position of a signal’s

transitions occurring at a rate greater than

a specified frequency, typically 10Hz

Alignment Jitter

SD HD 3Gb/s

0.2UI (740ps) @ 1kHz

0.2UI (135ps) @

100kHz

0.3UI (101ps) @

100kHz MaximumPreferred 0.2UI

(67.3ps) @ 100kHz

Timing Jitter (10Hz)

SD HD 3Gb/s

0.2UI (740ps) 1.0UI

(673.4ps @ 1.485Gb/s)

(674ps @ 1.4835Gb/s)

2.0UI

(673.4ps @ 2.97Gb/s)

(674ps @ 2.967Gb/s)

Jitter Measurements� Timing Jitter

� Alignment Jitter

33


Eye and Jitter Measurements at a Glance

� Physical Layer Measurements at a Glance

� Multiple Eye Displays

– 3 Eye, 10/20 Eye

� Two Jitter Measurement

– Timing Jitter

– Alignment Jitter

� Automated Eye Measurements

– Amplitude

– Rise/Fall Time

– Cable Length Measurements

– Two Jitter Readouts


Transmission Path VerificationEye test procedure

1. Initial cable length – test signal

2. Increase cable length (87 m)

� Amplitude decrease

� Reduced Frequency Response

� Increased Rise & Fall Times

� Eye Opening barely discernible

� Jitter does not change

3. Increase cable length (> 120 m)

� Non Discernible Eye

� No Errors Indicated

� Equalizer still able to recover

4. See equalized eye

� A receiving device could still recover

the data

2/17/20103636

HD Eye Measurement

80%

20%

AmplitudeAmplitude

Rise Time

Rise Time

Fall Time

Fall Time

Auto MeasureAuto Measure

2/17/20103737

Jitter Display and Measurement

� Demodulation method

� Shows jitter related to video

line and field rates

� Launch amplitude of device

should be less than 0.2UI


SMPTE424M Signal/Data Serial Interface

� Defines the transport of bit-serial data structure for 3.0Gb/s

� Using a single coaxial cable interface

� Supports either 10 or 12 bits data words

� Mapped into two virtual interfaces

– 10 bit parallel data streams (Data Stream One & Data Stream Two)

Data stream one of the virtual interface

Interface Frequency 148.5MHz or

148.5/1.001 MHz

Data stream two of the virtual interface

Interface Frequency 148.5MHz or

148.5/1.001 MHz

SA

V

EA

V

+ L

ine

No

. +

CR

C

Digital Active Line

Active Picture or Ancillary Data

SA

V

Digital Line Blanking

Blanking Level or Ancillary Data

SA

V

EA

V

+ L

ine

No

. +

CR

C

Digital Active Line

Active Picture or Ancillary Data

SA

V

Digital Line Blanking

Blanking Level or Ancillary Data

Digital Line Period


Tektronix patented Timing display


Tektronix patented Timing display


Timing Measurement – Using Lightning display

� Bowing indicates a timing error

4 Direction shows advance or delay

4 Location shows which component is at fault

4 Crosshairs quantify

2/17/20104242

Pathological Signals - Stress TestingSDI Checkfield

20 BITS

19 BITS

1 BIT

20 BITS

HORIZONTAL ACTIVE LINE ONLY

� Condition occurs once per field for a complete line

VERTICAL BLANKING INTERVAL

FIRST HALF OF ACTIVE FIELD

300h, 198h

FOR CABLE EQUALIZER TESTING

SECOND HALF OF ACTIVE FIELD

200h, 110h

FOR PHASE LOCKED LOOP TESTING

2/17/20104343

Digital Closed Captions

� HD 708 Captions are a data stream in the VANC of the SDI video

2/17/20104444

Ancillary header flag with examples

000

ADF

3FF,3FF

ADF 2E7

DID

21B

SDID

/DBN

218

DC

2/17/20104545

Simultaneous Closed Caption Display

2/17/20104646

� AFD describes the aspect ratio of video signals

� AFD codes embedded in video signals using SMPTE 2016-3

� Allow video processing equipment to correctly format the picture

� Used by display devices and set-top boxes to automatically control how pictures are formatted

� Various methods have been used in Europe for these type of aspect ratio formatting

– Wide-Screen Signaling (WSS)

– Video Index

Active Format Description

46


� SMPTE 2016 – 1 Format for Active Format Description and Bar Data

� SMPTE 2016 – 2 Format for Pan-Scan Information

� SMPTE 2016 – 3 Vertical Ancillary Data Mapping of Active Format Description and Bar Data

� SMPTE 2016 – 4 Vertical Ancillary Data Mapping of Pan-ScanInformation

� ATSC A/53 – AFD Carriage in MPEG2

� CEA-CEB16 – Digital Receiver Guidelines

Standards Documents

47

2/17/20104848

Waveform Monitor Picture View with AFD

2/17/20104949

Multi-Channel Audio MonitoringSurround Sound Display

� Allows visualization of interaction between multiple channels

– Left (L), Right (R), Center (C), Left Surround (Ls), Right Surround (Rs)

– Show Dominant Sound

– Correlation between channels

– Phantom Phase Indicators

– Linear or A Weighting Filters

2/17/20105050

Phantom Source Indicators

� Associated with each channel pair

� Provides indication on the localization of the sound

� White tic mark indicates correlated sound (+1)

� Slightly Correlated (<0.9)

� Negative Correlation (<0.2)

� Out of Phase (-0.3)

2/17/20105151

Configuring Loudness Measurement

� Select Weighting Filter

� Select Duration

� Select Start & Stop Time

� Leq or LAeqmeasurements

– Individual Channel

– Channel Pairs

– Selected Channels

– 10 second Short Average

– Program Average

True PeakAudio Level

2/17/20105252

ITU-R Template

C'C

Detectability Threshold

Unacceptability Threshold

Sound Advanced wrt

Vision

Sound Delayed wrt

Vision

Undetectability Plateau

B B'

A A'

-2

-1.5

-1

-0.5

0

-200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100

Delay time (ms)

Su

bje

cti

ve

Eva

lua

tio

n R

es

ult

s (

Dif

fgra

de

)


AV Delay Measurement Audio Advanced

� Measurement made on a AMM768

� Or on a WFM7120

� Or on a WVR7120