How to get all this new stuff to work

Karl Kuhn Sr. Applications Engineer

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Don’t Worry- It‘s Digital

• It Just Works

• Analog Degrades Gracefully◦ It Tells You All Its Aches and Pains

◦ Window into Electronic World

◦ You Decide

• Digital Has Cliff Effect◦ It Tells You Nothing –

◦ Digital is Analog but Digital Decides

◦ Baseline

◦ Intensive Care Ward

◦ EVERYONE Has This All Figured Out

• Interoperability- All devices are Guilty

• Big Circuit Board

• Testing is Too Expensive

• Breaking the Law

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High Level Testing Concepts

• Quality of Service (QoS)-- Analog one to one◦ Perhaps Totally Transparent to End User

◦ Error Rates

◦ Bandwidth

◦ Transmission Multipath

◦ Jitter

• Quality of Experience (QoE)◦ The End User Will Notice and The Phone Will Ring

◦ Long Access Times

◦ Buffer Wait Times

◦ Black Frames

◦ Freeze Frames

◦ Blockiness

◦ Slice Errors

◦ Loudness and Level Issues

◦ Closed Captioning

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Black Burst Tri Level and SDI are last holdouts

27 MAY 2016

MERGING TOGETHER: IT AND BROADCAST ENGINEERING

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IT Engineer

• Layers, Outages and Configuration

• Network traffic

• NTP and PTP

• Less sensitive to the impact of bit errors

• QoE centric mythology

• Data can be reset- not the case with Video

• Challenge is understanding video technology

Video Engineer

• The Content- Video Audio Metadata

• Patch Panel

• Black Burst and Tri Level Sync

• Importance of delivering signal quality

• QoS centric methodology

• SDI vs IP IP is an Abstraction

• Challenge is understanding IT technology

CH1

CH2

MCR

Presentation Control

Transcode

Origin Server (ABR)

VoD Providers

Telecom/3GPP

Provider

Local Content and Ads

HD Encode

SD Encode

Edit Metadata Graphics

Content Processing

Central

Storage

Ingest

Content

GroomingSD-SDI, HD-SDI, 3G-SDI

ASI, IP, RF

Monitoring Need:

• Video errors and compliance

• Audio errors and compliance

• Audio Loudness

• Closed Caption and Metadata Errors

Monitoring Need:

• Encoder quality

• Post mux video and audio QoE

• IP and TS structure errors

• Splicing, EBI, tru2way Errors

Filebased Formats

Monitoring:

• Video & Audio QoE + Codec Errors

• Audio QoE and Audio Codec Errors

• File Wrapper structure

• Loudness monitoring and correction

Splice, Encrypt

Modulate

Adaptive Bit Rates and Streaming

Monitoring:

• Profile availability

• Packet structure & Packet rate

• Manifest file verification

Monitoring Points

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To

BDUs

4096x2160

3840x2160

Image Sizes

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1920x1080

1280x720

720x480

720x576

Quad SDI

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In SDI we break the screen into quadrants

3840 X 2160 equals four 1080P images

4096 X 2160 equals four 2K images

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Inter Link Timing

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• Quad-link 3G-SDI requires all 4

cables to be timed precisely

◦ A ¼ wavelength at 3 GHz is only 2.5

cm

◦ 2.97 Gb/s @ 60 Hz has a 148.5 MHz

clock with period of ~6.7 ns

• SMPTE ST-425-5 says Link A to

Link D shall not exceed 400ns at

the source (1187 clock cycles)

• No specification is given for the

receiving device

◦ Equipment needs to balance timing

tolerance with buffering

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SDI Stability Measurements

Eye Pattern Distortions

Long cable

Decrease in amplitude

Decrease in Frequency

response

Eye opening narrows

Rise/Fall time increases

Termination

Incorrect termination

causes overshoot and

undershoot

Shift in Eye Crossing

Shifts 50% point of eye

opening

Caused by unequal rise or

fall time

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Waveform View HD UHD or 4K

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Waveform YRGB view

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3840

Pixels

3840

Pixels

3840

Pixels

3840

Pixels

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Check Flat Field

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Wide Color Gamut – DCI-P3, 709, 2020

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Diamond Display - Live Signal Gamut Errors

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Diamond Display - Live Signal Gamut Errors

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Diamond Display - Live Signal Gamut Errors

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Diamond Display – Live Signal Corrected

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Diamond Display – Camera Balancing

Black Center

White Outer

Apex

White Outer

Apex

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Split Diamond – Camera Balancing Red Error

Deviation from

vertical

indicates color

balance error

In this case a

Red Gain

Error

Deviation from

center

indicates color

balance error

Black Offset in

Red Channel

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Diamond Display – Camera Balancing Live

Keep signal

within graticule

Adjust luma in

vertical axis

Black balance

in center of

display

Remember

color

component

axes

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Picture Bright Up

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Gamut Error –Turn On The PICTURE BRIGHT UP !

Yellow

Error

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High Dynamic Range- HDR

• High Dynamic Range

◦ Not screen distance dependent

◦ Brighter Whites with Detail

◦ Blacks with Detail

◦ Not just more contrast

◦ Bright will cause viewer fatigue

◦ Video Loudness

Image reproduction using video is perfect if display light pattern matches scene light pattern.

Linear Camera

Linear CRT

Lightness perception

only important for S/N

considerations.

RGB

If camera response were linear,

>15-bits would be needed

and MPEG & NTSC S/N fidelity

would need to be better than ~90 dB.

Current driven CRT

or new flat-panel display

D65 daylight

1/3 power-law “cube-root” ~100 steps (15 bits)

NTSC & MPEG

(8 bits)

Need to match light output

But do not look the same!

Perceptually uniform steps

Image reproduction using video is perfect if display light pattern matches scene light pattern.

CRT response

Lightness perception

only important for S/N

considerations.

RGB

D65 daylight

light source

1/3 power-law “cube-root”

Thanks to the CRT gamma, we

compress the signal to roughly

match human perception and only

7 bits is enough!

Need to match light output.

Look the same with only 7-bits

8-bits

~100 steps (7-bits)

1 JND

1 JND

1 JND

HDR Waveform

Specular highlight

is going to the top

Normal White is at

59%

18% black is at

32%

We have placed

cursers at 59%

and 32%

Highlight is from

the silver ball

Spider Cube

Log C to PQ Curve

SMPTE Levels

540 or 1000 Nits

Max Highlights

Monitor dependent

~100-200 Nits

Normal White

20 Nits

18% Grey

Reflective Black

Log C to Rec. 709

Log C HDR Waveform to Nits

540 or 1000 Nits

Max Highlights

Monitor dependent

100 Nits

Normal White

20 Nits

18% Grey

High Frame Rate- HFR

• Real life is HRF-- TV 30/60 fps-- with move to 120 fps

• Cinema is 24 fps- provides suspension of disbelief

• Sports and Advertising loves HFR- Addictive

• Digitally Emulate 24 fps film requires frame rate conversion

• 1M fps http://www.visionresearch.com

27 MAY 201636

IP Status

• Check the overall incoming stream status

• Pie chart with traffic information in a 10GbE pipe

• Select a stream to monitor

27 MAY 2016 37

IP Measurement

• Ensure the system healthiness over the time. Compare the trend between SDI and IP to investigate the root cause.

• Histogram - Packet interval time

• Trend Graph - Packet interval time, RTP packet loss / out of order, Bit Rate, SDI / CRC error

27 MAY 2016 38

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IP Graphing – Packet Interarrival Timing (PIT)

Packet Interarrival Time GraphingMax, Min, Mean

IP/PTP Session

27 MAY 2016 40

Layer 2VideoPTP

PTP Delay/Variance

• Monitor the PTP stability in the IP system

◦ Measure the T-ms and T-sm

27 MAY 2016 41

Sync

Follow-up

Delay Request

Delay Response

Primary

Master TimeBackup

Slave Timet1

t2

t3

t4

Slave

Knows

t2

t1, t2

t1, t2, t3

t1, t2, t3, t4

T-ms

(t2 – t1)

T-sm

(t4 – t3)

PTP StatusPTP Lock Status

Status of the two Domains

Number of steps from the GM

Clock value of the GM

MAC Address of for GM

Lock values for the Slave Mode

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Picture Quality Measurements - PSNR

• PSNR – Peak Signal to Noise Ratio

• PSNR shows the ratio between the peak signal amplitude and

the RMS noise between the reference and test video

• Scale (expressed in dB):

◦ No difference between Ref & Test = Infinite

◦ Good Quality = Higher dB value

◦ Poor Quality = Lower dB value

• Use for:

◦ Detecting and diagnosing problems in video processing hardware, software and

algorithms

◦ Quick checks to detect possible picture quality problems

• PSNR is not a direct prediction of what human viewers will

perceive

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Picture Quality Measurements - PQR

• PQR – Picture Quality Rating

• Developed for the PQA200/300

• Based on Just Noticeable Difference (JND) concept

• 1 PQR = 1 JND

◦ 75% of viewers will notice a difference

◦ Difference is just barely noticeable

• Scale:

◦ No difference between Ref & Test = 0

◦ Good Quality = Low Number

◦ Poor Quality = High Number

• Absolute measurement: Measurement results do not depend on

any training video sequence

• Use to determine how much viewers will notice differences

between the reference and test videos

• Most meaningful for differences near the visibility threshold

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Picture Quality Measurements - DMOS

• DMOS - Difference Mean Opinion Score

• Simulating the DSCQS (double stimulus C continuous Quality

Scale) method described by ITU-R BT.500

• Scale:

◦ No difference between Ref & Test = 0

◦ Good Quality = Lower number

◦ Poor Quality = Higher number

• Relative measurement: Measurement results depend on worst

case training sequence response used to configure measurement

• Use for assessing picture quality:

◦ Over a wide range of quality levels close to or far from the visibility

threshold

◦ Relative to a baseline “worst case” picture quality specific to an

application or situation

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Attention Model and Attention Weighting

• The Attention Model predicts the viewer’s focus of attention within the image.

• Highlighted regions show the viewer’s focus of attention.

◦ More focus on the jogger

◦ Less attention paid to the two other walkers

• This model can be used in conjunction with other measurements and provides a weighting to PSNR or Predicted

DMOS.

• For example, can be used to optimize specialized encoding for sports programming.

Reference Attention Map

Testing Methodology

How to get all this

new stuff to work

27 MAY 2016

Karl KuhnSr Video Apps Eng

karlku@tek.com

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