Thanks On Aug 17, 2016 6:25 AM, "Clément Bœsch" <u...@pkh.me> wrote:
> On Mon, Aug 15, 2016 at 07:04:56PM -0700, Sasi Inguva wrote: > > Changes done. Also commented in the code about the differences between > the add_index_entry function and teh ff_add_index_entry function. > > > > About stream copy, yes there will be a big behavior difference when > doing "-c copy" for files with edit lists. > > Currently, ignoring edit lists we will copy all packets from input to > output. So for videos with edit lists the current way of stream copy is > already semantically wrong. In summary these will be the changes with this > patch > > i) For videos with no edit lists - no change. > > ii) For videos with one edit list in their streams > > - Only portion of the video from the closest keyframe before > the edit list begins, to the closest keyframe after the edit list ends will > be copied. > > - All audio from the start of the audio stream to the end of > the edit will be copied. > > > > iii) For videos with multiple edit lists in their streams > > - For video, the timestamps can be non-monotonocially > increasing. Keyframe packets might be repeated. etc. > > - For audio too, timestamps can be non-monotonically > increasing. For each edit list we will output packets from the start of the > audio stream, so audio will be repeated. > > > > Though points (ii) and (iii) might look dangerous, we should keep in > mind that it is very hard, and maybe impossible to implement proper stream > copy of only those portions of streams which are inside edit lists. We need > a way to mark some frames as decode-and-discard, and maybe writing edit > lists in case of MOV container is a way but if we are doing -c copy to > some other container, it won't be possible mostly. If (ii) and (iii) sound > unacceptable I can gate the mov_fix_index function behind a no-stream-copy > condition, if there is a way to do so. > > > > OK. > > So. I've made some test with a bunch of personal samples from different > different sources and it fixes the playback for all of them. I don't have > much more comment as it seems to work well. I'm not the maintainer of the > MOV demuxer though, so don't take this as a OK. > > Someone should probably do a deeper review (hint: look at mov_fix_index() > in particular) > > Thanks > > -- > Clément B. > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel