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[FFmpeg-devel,v2,0/2] avformat/mvdec: make audio stream conditional

Message ID 20220101011148.13921-1-jpstewart@personalprojects.net
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John-Paul Stewart Jan. 1, 2022, 1:11 a.m. UTC
Changed in v2:
    Allocate the audio stream first to maintain consistent behaviour
    with prior code.

Recent discussion on the list led me to realize that libavformat was
unconditionally creating an audio stream for all SGI movie format
(version 2) files, even when no audio is present in the file.  

A sample of a movie file with no audio can be found at
    http://www.personalprojects.net/ffmpeg/silent.movie

Unpatched ffmpeg will report an audio stream even though no audio is
present.  After the following patch no audio stream is reported.

Incidentally, the silent.movie sample above is at 25fps and can also be
used by anyone who wants to double-check the earlier patch 3c9ffbd009
that reads and sets the framerate.  The sample file is only about 88 KB.