John-Paul Stewart: > On 2021-12-31 17:19, Andreas Rheinhardt wrote: >> John-Paul Stewart: >>> 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. >>> >>> SGI movie files with audio are slightly affected by the fact that the >>> audio stream is now allocated after the video stream, changing the order >>> they are listed in the output of ffprobe or ffmpeg. I don't think this >>> materially affects anything. All existing FATE tests pass. >>> >> >> If I am not mistaken, it actually changes it a bit more: The audio data >> (if present) is stored before the video data in the file and >> mv_read_packet returns the data in the order of the stream numbers. Now > > Thanks for that info. I hadn't realized that mv_read_packet relied on > the order of the stream numbers. >
It is actually documented (right before creating the audio stream): "/* allocate audio track first to prevent unnecessary seeking * (audio packet always precede video packet for a given frame) */" - Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
