Implementing AFD
at PBS member station WSIU
Terry Harvey
WSIU/ Southern Illinois University,
Carbondale Illinois
AFD – What is it?
AFD is Active Format Description: defines
aspect ratio.
 AFD is used to define how the video originating
in one aspect ratio may be “optimally” displayed
on a display of a different aspect ratio.
 AFD metadata is carried in baseband video and
in an MPEG2 transport stream.

AFD broadcast from WSIU
All HD programs and interstitials have AFD
added.
 AFD no benefit to consumer DTV receivers:

 Older DTV receivers do not use AFD
 Newer DTV receivers are 16:9 and HD AFD not
required!

Cable and DTH Satellite benefit from AFD:
head end IRD correctly formats for 4:3.
Complete list of AFD codes
Values from ETSI TS 101 154 V1.7.1 Annex B, ATSC A/53 Part 4 and SMPTE 2016-1-2007
0
ESTI: reserved; ATSC: undefined
1
reserved
2
ETSI: 16:9 active picture (top aligned); ATSC: "not recommended"
3
ETSI: 14:9 active picture (top aligned); ATSC: "not recommended"
4
ETSI: box > 16:9 (center): wider than 16:9 active picture. The aspect ratio of the source area is not given, and the size of the
top/bottom bars is not indicated.
ATSC: bar data (indicating the extent of top, bottom, left, and right bars) should be transmitted when using this code.
5–7
reserved
8
Full Frame image, same as the frame (4:3 or 16:9).
9
4:3 Image: Full Frame in 4:3 frame, Pillarbox in 16:9 frame.
10
16:9 Image: Letterbox in 4:3 frame, Full Frame in 16:9 frame.
11
14:9 Pillarbox/Letterbox image.
12
unused
13
4:3 with shoot and protect 14:9 centre. The term "shoot and protect" is not explained in the standard, but means that the areas
above and below the central 14:9 region of the 4:3 active picture can be trimmed without losing important detail.
14
16:9 with shoot and protect 14:9 centre. Here, the areas to the right and left of the central 14:9 region of the 16:9 active picture
can be trimmed without losing important detail.
15
16:9 with shoot and protect 4:3 centre. Here, the areas to the right and left of the central 4:3 region of the 16:9 active picture can
be trimmed without losing important detail.
List of AFD codes that benefits us
Values from ETSI TS 101 154 V1.7.1 Annex B, ATSC A/53 Part 4 and SMPTE 2016-1-2007
8 - Full Frame image, same as the frame (4:3 or 16:9).
9 - 4:3 Image: Full Frame in 4:3 frame, Pillarbox in 16:9 frame.
10 -16:9 Image: Letterbox in 4:3 frame, Full Frame in 16:9 frame.
15 -16:9 with shoot and protect 4:3 centre. Here, the areas to the
right and left of the central 4:3 region of the 16:9 active picture
can be trimmed without losing important detail.
List of AFD codes that we need only use.
Values from ETSI TS 101 154 V1.7.1 Annex B, ATSC A/53 Part 4 and SMPTE 2016-1-2007
8 (1000)
Full Frame image, same as the frame (4:3 or 16:9).
9 (1001)
4:3 Image: Full Frame in 4:3 frame, Pillarbox in 16:9 frame.
Without Broadcast AFD
HD Broadcast
Cable TV
Forced
Letterbox
AFD absent
Forced
Center Cut
AFD absent
With Broadcast AFD
HD Broadcast
Cable TV
AFD Controlled
Center Cut
AFD 1001
AFD Controlled
Letterbox
AFD 1000
How is the AFD conveyed?

AFD will be carried in HD and SD baseband Serial
Digital Video Interface in the VANC as per
SMPTE-334M. (HD-SDI VANC line 11).
How is the AFD conveyed?

In ATSC over-the-air transmission, the AFD is
carried in the picture user data bits in MPEG2
Transport Stream.
sport Stream Packet
Transport Stream Packet
Transport Stream Packet
Header
Transport Stream Packet
Video Payload
Adaptation Field
Picture User Data Bits
Transport Stream P
AFD: Practical Implementation
Must ensure a correct AFD code is applied to all
program elements in HD broadcast: eg. HD and
upconverted SD content.
 HD and SD AFD is supported but PBS does not
yet forward SD-AFD.
 Member station must therefore generate AFD for
SD and all local content.

Prerequisites for AFD- IRDs
IRDs (Satellite Receivers): Older IRDs (BitLinks)
do not employ AFD decoding (eg extraction of
AFD from transport stream and placement in
HD-SDI VANC).
 Sencore MRD3187 IRDs do employ AFD (Note
earlier MRD3187B’s need upgrading).
 ASI interface on Bitlink will convey AFD.

Prerequisites for AFD - Servers
Most servers now record and playback HD and
SD AFD.
 AFD extracted from baseband input VANC stored
with caption data in auxiliary referenced file.
 AFD extracted from transport stream when
recorded via ASI must be stored and made
available for baseband VANC playback.

Prerequisites for AFD - Encoders
AFD carried in HD-SDI VANC must pass through
the master control switcher and applied to the
MPEG2 Emission Encoder.
 Encoder must be capable of extracting AFD from
HD-SDI VANC and placing AFD in MPEG2
transport picture user data bits.

Example AFD Implementation
AFD on HD-SDI
IRD - HD
IRD - SD
Upconverter
HD-SDI
AFD on HD-SDI
Includes AFD
HD Source
SD Source
Video Router
Automation GPI Control
of Preset AFD codes
and aspect ratio
Universal
Converter
Includes AFD
Video
Server
Master
Control
Switcher
HD
Emission
Encoder
Another Example
IRD - HD
Automation GPI Control
of Preset AFD codes
and aspect ratio
No AFD on HD-SDI
HD-SDI
HD Source
SD Source
Video Router
Video
Server
Universal
Converter
Includes AFD
Master
Control
Switcher
AFD
Insertion Card
HD-SDI with AFD
HD
Emission
Encoder
To Ensure the Highest Quality
Minimize unnecessary codec cycles.
 Minimize unnecessary video rescaling eg. 480i to
1080i then to 720p for emission.
 Record Full Frame 16:9 and 4:3, no local pillarbox
or letterbox.
 All locally produced programming in HD and SD is
now 16:9 format.
 SD to HD Upconvertor controlled by automation to
correct format and add AFD.

WSIU - HD AFD
Satellite receiver provides HD AFD from PBS.
 Server records and playbacks HD AFD.
 File based HD local production has HD AFD added at
Transcode/ Transwrap when transferred to Omneon
server.
 Three HD AFD format codes:

 16:9 FF AFD codes 1000
 16:9 FF center cut safe AFD code 1111 (from PBS)
 16:9, 4:3 Pillarbox AFD code 1001
WSIU - SD AFD
All SD recorded and archived as native SD.
 Local SD file base production has no AFD.
 SD playback upconvert to air where AFD is added.
 SD four formats:

 16:9 Full Frame AFD code 1000
 16:9, 4:3 Pillarbox AFD code 1001
 4:3, Full Frame AFD code 1001
 4:3, 16:9 Letterbox AFD code 1000
FCP files from Post Production
Transcode
Adds AFD
To HD
AMC21 IRDs
Ku22
Sencore
HD01 HD02
IRD
Ku23b
SD05
Sencore
IRD
Sencore
IRD
Ku23c
SD06
Sencore
IRD
Ku23d
SD07
Sencore
IRD
Omneon
MIP-5321
Omneon
MIP-4010
ASI ROUTER
Ku23a
HD04
Omneon
MIP-4010
Omneon
MIP-4010
Omneon
MIP-4010
VDCP
Omneon
Spectrum
Video
Server
Omneon
MIP-5321
Omneon
MIP-5321
Omneon
MIP-4010
Omneon
MIP-4010
ASI Record Ports
for SD and HD
1080i
Evertz
7812 CC
480i
Evertz
7812 UDX
720p
VDCP
720p
GPI for Aspect Ratio
and AFD
VDCP
Ku24
Sencore
HD03 SD01
IRD
720p
NVerzion
Automation
ProTrack
720p Master Control Switcher
WSIU 720p Master Control with AFD
720p
ProTrack Database
Record for SD 16:9
ProTrack Database
Record for SD 16:9
ProTrack facilitates
identification of
aspect ratio.
ProTrack Database
Record for SD 16:9
ProTrack also
differentiates between
video formats
1080i , 720p and 480i:
Each can be 16:9.
WSIU Playlist
SVR1A – HD Playback
SVR1B – SD Playback
Formats for SVR1B (SD)
NS = 4:3 Full Frame
LB = 4:3,16:9 Letterbox
WS=16:9 Full Frame
PB =16:9,4:3 Pillarbox
AFD for SVR1A (HD)
-from HD File
AFD for SVR1B (SD)
NS = 9 (1001)
LB = 8 (1000)
WS = 8 (1000)
PB = 9 (1001)
AFD – It Does Work!
PBS began applying AFD to HD programs April 2009.
 WSIU began broadcasting AFD in July 2009.
 All WSIU programming and individual WSIU interstitials
have AFD applied.
 Broadcast SD Distributors using WSIU AFD:

 DirecTV and Dish Network July 2009
 Charter Communications September 2009
 MediaCom July 2010