[FFmpeg-trac] #964(undetermined:new): No h263 Mode B support?

[FFmpeg]

#964: No h263 Mode B support?
-------------------------------------+-------------------------------------
             Reporter:  walker       |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:  h263 mode    |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 It appears that Mode B support for h263 is not supported?

 I have a h263 over RTP stream dump from a commercial videophone that
 includes both Mode A and Mode B.

 From this thread on ffmpeg-devel, I'm taking it that only Mode A was ever
 supported?

 https://lists.libav.org/pipermail/ffmpeg-devel/2009-April/067074.html

 I have tested the attached stream on four different commercial
 videophones. They all reproduce the video flawlessly. ffmpeg renders the
 Mode A packets, but simply prints out errors for the Mode B packets.

 I am attaching three files:

 demo.h263: The raw stream that is sent both to and from a videophone. H263
 + RTP.

 ffmpeg.out: The output from ffmpeg -i demo.h263 demo.mp4

 demo.mp4: The ffmpeg-generated mp4 from the h263 stream. It seems that
 only the Mode A packets are interpreted by ffmpeg, so the video looks
 quite corrupted.

 Sample error output from the attached+complete ffmpeg.out dump:

 [h263 @ 0x7f86b083fc00] Bad picture start code
 [h263 @ 0x7f86b083fc00] header damaged
 [h263 @ 0x7f86b083fc00] I cbpy damaged at 20 0
 [h263 @ 0x7f86b083fc00] Error at MB: 20
 [h263 @ 0x7f86b083fc00] illegal ac vlc code at 0x14
 [h263 @ 0x7f86b083fc00] Error at MB: 322
 [h263 @ 0x7f86b083fc00] I cbpy damaged at 2 15
 [h263 @ 0x7f86b083fc00] Error at MB: 347
 [h263 @ 0x7f86b083fc00] I cbpy damaged at 1 5
 [h263 @ 0x7f86b083fc00] Error at MB: 116
 [h263 @ 0x7f86b083fc00] run overflow at 1x16 i:1
 [h263 @ 0x7f86b083fc00] Error at MB: 369
 [h263 @ 0x7f86b083fc00] illegal dc 128 at 0 5
 [h263 @ 0x7f86b083fc00] run overflow at 1x5 i:1
 [h263 @ 0x7f86b083fc00] Error at MB: 116
 [h263 @ 0x7f86b083fc00] concealing 396 DC, 396 AC, 396 MV errors

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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/964>
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