| Value | Meaning |
|---|---|
| UNAVAILABLE0 | Unavailable (see note 0 below). |
| _16_9_TOP_ALIGNED2 | For 4:3 coded frame, letterbox 16:9 image, at top of the coded frame. For 16:9 coded frame, full frame 16:9 image, the same as the coded frame. |
| _14_9_TOP_ALIGNED3 | For 4:3 coded frame, letterbox 14:9 image, at top of the coded frame. For 16:9 coded frame, pillarbox 14:9 image, horizontally centered in the coded frame. |
| GREATER_THAN_16_94 | For 4:3 coded frame, letterbox image with an aspect ratio greater than 16:9, vertically centered in the coded frame. For 16:9 coded frame, letterbox image with an aspect ratio greater than 16:9. |
| _4_3_FULL_16_9_FULL8 | For 4:3 coded frame, full frame 4:3 image, the same as the coded frame. For 16:9 coded frame, full frame 16:9 image, the same as the coded frame. |
| _4_3_FULL_4_3_PILLAR9 | For 4:3 coded frame, full frame 4:3 image, the same as the coded frame. For 16:9 coded frame, pillarbox 4:3 image, horizontally centered in the coded frame. |
| _16_9_LETTER_16_9_FULL10 | For 4:3 coded frame, letterbox 16:9 image, vertically centered in the coded frame with all image areas protected. For 16:9 coded frame, full frame 16:9 image, with all image areas protected. |
| _14_9_LETTER_14_9_PILLAR11 | For 4:3 coded frame, letterbox 14:9 image, vertically centered in the coded frame. For 16:9 coded frame, pillarbox 14:9 image, horizontally centered in the coded frame. |
| _4_3_FULL_14_9_CENTER13 | For 4:3 coded frame, full frame 4:3 image, with alternative 14:9 center. For 16:9 coded frame, pillarbox 4:3 image, with alternative 14:9 center. |
| _16_9_LETTER_14_9_CENTER14 | For 4:3 coded frame, letterbox 16:9 image, with alternative 14:9 center. For 16:9 coded frame, full frame 16:9 image, with alternative 14:9 center. |
| _16_9_LETTER_4_3_CENTER15 | For 4:3 coded frame, letterbox 16:9 image, with alternative 4:3 center. For 16:9 coded frame, full frame 16:9 image, with alternative 4:3 center. |
Enumeration of the various values for Active Format Description (AFD)
AFD should be included in video user data whenever the rectangular picture area containing useful information does not extend to the full height or width of the coded frame. AFD data may also be included in user data when the rectangular picture area containing useful information extends to the full height and width of the coded frame.
For details, see Table 6.14 Active Format in:
ATSC Digital Television Standard: Part 4 – MPEG-2 Video System Characteristics
https://www.atsc.org/wp-content/uploads/2015/03/a_53-Part-4-2009.pdf
and Active Format Description in Complete list of AFD codes
https://en.wikipedia.org/wiki/Active_Format_Description#Complete_list_of_AFD_codes
and SMPTE ST2016-1
Notes:
1) AFD 0 is undefined for ATSC and SMPTE ST2016-1, indicating that AFD data is not available: If Bar Data is not present, AFD '0000' indicates that exact information is not available and the active image should be assumed to be the same as the coded frame. AFD '0000'. AFD '0000' accompanied by Bar Data signals that the active image’s aspect ratio is narrower than 16:9, but is not 4:3 or 14:9. As the exact aspect ratio cannot be conveyed by AFD alone, wherever possible, AFD ‘0000’ should be accompanied by Bar Data to define the exact vertical or horizontal extent of the active image. 2) AFD 0 is reserved for DVB/ETSI 3) values 1, 5, 6, 7, and 12 are reserved for both ATSC and DVB/ETSI 4) values 2 and 3 are not recommended for ATSC, but are valid for DVB/ETSI