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 that you have reversed the order in which the streams are created, there will be seeks; in particular, the file needs to be seekable. This can be fixed by inverting the order in which packets are read in mv_read_packet and by also creating the video streams for the non-version-two files before the audio streams. > 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. > _______________________________________________ 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".
