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Navigating the DTV Transition: How Broadcasters are Using AFD to Maintain Formatting Control of their Programming

Clarence Hau: NBC-UniversalSMPTE Technical ConferenceOctober 28, 2008

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AFD describes the aspect ratio of video signalsAFD codes embedded in video signalsUsed by display devices to automatically control how pictures are formatted

• Used widely in Europe

Industry Documents• ATSC A/53, DVB, Others : AFD Carriage in MPEG2• CEA-CEB16 : Digital Receiver Guidelines• SMPTE 2016-1/3: AFD Carriage in Baseband

Video (VANC)

BackgroundAFD = Active Format Description

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New Application for the DTV Transition (112 days away)

• Automatic control of down-conversion• Optimum formatting for SD viewers

How is AFD being utilized to solve Post DTV Transition down-conversion issues?What methods are in use by broadcasters?How much progress has been made?

IntroductionAFD for the DTV Transition

4ANALOG AND DTV SIGNALS OFF-AIR

Broadcast Television ReceptionToday

TelevisionBroadcaster

HDTV Set

Analog Set

DTV Signal

Analog Signal

5ANALOG SHUTDOWN - DTV SIGNALS ONLY*

Broadcast Television ReceptionPost DTV Transition

TelevisionBroadcaster

HDTV Set

Analog Set

DTV Signal

DTV ConverterBox

6INDEPENDENT / CONTROLLED DELIVERY PATHS

Broadcast Station DistributionToday

TelevisionBroadcaster

HDTV Set

Analog Set

DTV Signal

Analog Signal

Cable/SatelliteProvider

7ANALOG VERSION FORMATTED AT HEAD-END

Broadcast Station DistributionPost DTV Transition

TelevisionBroadcaster

HDTV Set

Analog Set

DTV Signal

Cable/SatelliteProvider

Down-conversion

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Down-conversion OptionsChoice between “Center-cut” or “Letterbox”

HD Originated SD Originated

Original

Center-cut

Letterbox

“CENTER-CUT” IS MOST COMMON CHOICE

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Center-Cut Safe RulesProtects from Center-Cut Down-conversion

48% of Total Canvas

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Leonardo da Vinci’s The Last SupperOriginal Version

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Leonardo da Vinci’s The Last Supper“Center-Cut Safe” Version

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AFD – Active Format DescriptionDown-conversion Usage

• AFD Flags inserted into HD video content

• Provides Real-time Instruction to Down-Converters

• Used internally by NBC Since 2005

D/C

Full 16:9 HD

“Center-Cut Safe” HD

Letterboxed SD

Fullscreen SD

Under AFD Control

D/C

• Being implemented by FOX, PBS, Hearst-Argyle and other broadcasters

• ATSC RP on ATSC to Analog Down-conversion

• Widely supported on professional down-converting ATSC receivers

ALLOWS CONTENT CREATORS TO DECIDE

13AFD FIXES THE ASPECT RATIO PROBLEM

Broadcast Television ReceptionPost DTV Transition

TelevisionBroadcaster

HDTV Set

Properly formatted SD

DTV Signal w/ AFD

Cable/SatelliteProvider

Down-conversion

Under AFD Control

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AFD – Active Format DescriptionDefinition and Usage

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Simple ProtocolMany Touch PointsUsage is key to successImplementation Guidelines

1. Authoring / Production2. Plant Distribution / Data Preservation3. Local Station Distribution

AFD – Today

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Focus on HD plant - AFD for down-conversionAFD carriage in HD-SDI most feasible today –file based carriage limitedDefine down-conversion format (AFD) for all finished content to be airedInsert AFD at Final Stage of HD ProductionApply fixed AFD code to up-converted content

AFD – TodayAuthoring / Production Guidelines

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AFD Authoring / Production GuidelinesCommercial/Program Ingest Example

Ask content providers for down-conversion formatInsert AFD code at ingest pointMany AFD – VANC inserters availableInsure Playout Server Supports VANC Record/Playback

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AFD Authoring / Production Guidelines

ProductionSwitcher

AFDInsert

HD Distribution

Control Room Default to Center-cut or Letterbox

Down-convert

HD-SDI HD-SDIw/ AFD

Control Room Examples

Define AFD code for program/eventAFD pass through on pre-encoded contentAvoid cross-fades between AFD’s (switch in black)

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AFD Authoring / Production GuidelinesEdit Workflow Example

Minimal AFD support on NLE systemsInsert AFD code at final publish pointInsure VTR configured to pass AFD in VANC

Non-LinearEditing System

AFDInsert

Manual Set to Center-cut or Letterbox

Down-convert

HD-SDI HD-SDIw/ AFD

Playout Server HD-SDIw/ AFD

HD Distribution

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AFD Authoring / Production GuidelinesFile-based Workflow Example

Storage

Non-LinearEditing System

TranscodingSystem

Playout Server

Drop Folder

Final Project(e.g. 50 Mb MPEG2)

Playout Format w/ AFD(e.g. 18 Mb MPEG2)

HD-SDIw/ AFD

HD Distribution

AFD – VANC carriage in file based systems varyTranscoding systems supply the “glue”Insert AFD code at final publishing point

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Focus on HD plant - AFD for down-conversion VANC support in SD systems is minimalDefine AFD carriage to fixed VANC position within HD plantGuard against multiple AFD codes in signalAvoid cross fades between AFD codesInsure End-to-End VANC preservationConsider automation control of AFD insertion

AFD – TodayDistribution Guidelines

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Baseband Network delivery with AFDInsure AFD data on all content – data pass through Insure ATSC encoder supports AFD

AFD – Today Local Station Distribution Guidelines

Network HD FeedHD-SDI w/ AFD

HD-SDI w/ AFD

ATSCEncoder

DownConvert

Under AFD Control

Direct FiberDelivery

ATSCw/ AFD

Insert fixed AFD at up-conversion from SD plant – for center-cutLocal/syndicated HD programming likely center-cut in short-term

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ATSC Network delivery with AFDInsure AFD data on all content – data pass throughInsure ATSC encoder supports AFD

AFD – Today Local Station Distribution Guidelines

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Goal: Validate end-to-end AFD delivery and down-conversionKOB-TV

• Covers entire state of New Mexico with portions of Arizona and Colorado

• 57 translators in service – remaining analog

NBC• Provides mixture of letterbox/full screen content on SD • Full Screen: News, Sports, SD Originated Content• Letterbox: Most Entertainment, HD Commercials/Promos

KOB-TV – Albuquerque, NM On-air AFD Test : Sept 24-25, 2008

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KOB-TV – Albuquerque, New Mexico Broadcast Network Topology

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KOB-TV – AFD Test KOB-TV Station

NBC HD Distribution (with content specific AFD) Fixed AFD code inserted in KOB local signal pathAFD carried on KOB Broadcast DTV Transmission

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KOB-TV – AFD Test DirecTV and DISH Network

DirecTV manages LCF (Local Collection Facility) for DISH NetworkCenter-cutting at LCF since July 2008Switched KOB down-convert from fixed center-cut to AFD at LCF.Test covered all DirecTV and DISH SD viewers in New Mexico.

Recorded from DirecTV SD

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KOB-TV – AFD Test Comcast

KOB provides HD and SD fiber to ComcastK-Tech down-converting receiver used for off-air backup. Test covered most Comcast analog viewers in New Mexico.

Recorded from Comcast SD

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KOB-TV – AFD Test Translators

Virtually all KOB translators to remain analog after Feb ‘095 KOB’s translators upgraded with R.L. Drake receiver on DTV feed.

Recorded from Socorro,NM Translator

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KOB-TV – AFD Test Off-air

AFD controlled down-conversion on off-air DTV Converter boxesZenith, Insignia, Dish Network and Panasonic DTV Converter boxes

Recorded from Zenith STB

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AFD technology is ready todayUnderstand the potential pitfallsWide manufacturer support for HD-SDI, MPEG Better support on file-based systems neededStart small – simple implementations

ConclusionsAFD Implementation

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Thank you

www.nab.org/AFDReady