[FFmpeg-trac] #10888(avfilter:new): av_buffersink_set_frame_size does not pad final frame at EOF

[FFmpeg]

#10888: av_buffersink_set_frame_size does not pad final frame at EOF
-------------------------------------+-------------------------------------
             Reporter:  Andrew       |                     Type:  defect
  Wason                              |
               Status:  new          |                 Priority:  normal
            Component:  avfilter     |                  Version:  git-
                                     |  master
             Keywords:  buffersink   |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 `av_buffersink_set_frame_size` should always return the specified
 nb_samples, and zero pad the final frame if needed.
 It does not seem to.

 Docs for `av_buffersink_set_frame_size` say:
 > All calls to av_buffersink_get_buffer_ref will return a buffer with
 exactly the specified number of samples, or AVERROR(EAGAIN) if there is
 not enough. The last buffer at EOF will be padded with 0.

 (I assume `av_buffersink_get_buffer_ref` means `av_buffersink_get_frame`)

 https://ffmpeg.org/doxygen/trunk/group__lavfi__buffersink.html#ga359d7d1e42c27ca14c07559d4e9adba7

 How to reproduce:
 I modified `docs/examples/decode_filter_audio.c` to use
 `av_buffersink_set_frame_size` and print the nb_samples of each frame.
 I also had to change it to properly signal EOF to the decoder and
 filtergraph. It correctly returns 1469 samples for all but the final
 frame. And that frame contains nonzero data in the unset samples.

 {{{
 % ./decode_filter_audio_g
 https://streams.videolan.org/streams/wav/welcome.wav
 ...
 frame->pts 104299 frame->nb_samples 1469
 frame->pts 105768 frame->nb_samples 1469
 frame->pts 107237 frame->nb_samples 1469
 frame->pts 108706 frame->nb_samples 254
 INCORRECT nb_samples
 }}}

 This is the patch to the example to reproduce (based on ffmpeg git master
 194414f62d987ad831654c45fff6ee27898b832e):

 https://github.com/rectalogic/FFmpeg/compare/master...rectalogic:FFmpeg:av_buffersink_set_frame_size
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10888>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker