[FFmpeg-trac] #8343(avcodec:open): h261dec doesn't mark keyframes

[FFmpeg]

#8343: h261dec doesn't mark keyframes
-------------------------------------+-----------------------------------
             Reporter:  Lastique     |                    Owner:  (none)
                 Type:  enhancement  |                   Status:  open
             Priority:  wish         |                Component:  avcodec
              Version:  git-master   |               Resolution:
             Keywords:  h261         |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-----------------------------------
Comment (by Lastique):

 Replying to [comment:8 Balling]:
 > I frames are not the same as key frames. Only IDR frames are key frames
 in AVC/HEVC, e.g.
 >
 > Key frame is not about decoding the frame. It is about decoding all
 frames after the key frame.

 An I-frame is an IDR-frame if there is no prediction across the I-frame.
 Which there isn't in the H.261 spec.

 And in any case, the spec explicitly says the decoder should start
 displaying pictures starting with the one marked as Freeze picture
 release. Meaning that it guarantees that further pictures are decodable.

 > Marking all I frames as key frames is a bug in encoder.

 It is not, if the encoder knows/guarantees that I-frames are actual
 keyframes.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/8343#comment:9>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker