On Tue, Nov 5, 2019 at 4:52 PM Michael Niedermayer <mich...@niedermayer.cc> wrote: > Assuming this doesnt violate any specifications and assuming that > it works with all players. > Then it would make sense to select this value automatically based > on the stream timestamps or timebases. > maybe there could be still a -mov_timescale but with an option for > "auto" to autoselect a small one which allows accurate representation > of most streams
Michael, thanks for the feedback, I did consider this, but I am not that familiar with the code base of FFmpeg to know what the 'right' data fields to use are and at what point during the initialisation process of the movenc code it is valid to use them. There certainly seams to be a number of points at which the code tries to compute a lowest common multiple in the general FFmpeg code and a number of fields representing timebases, frame rates etc. If somebody can help point me at what I should use, then I'm happy to add something to automatically determine something. In terms of the specification, the Apple documentation certainly recommends the use of 600 on p221 of https://developer.apple.com/standards/qtff-2001.pdf for most integer frame rates, but as the following section in that document says this does not work for 23.976 or 29.97. For newer frame rates like 48 and any other number of 'new' content types, those number fail so whilst I'd suggest using the Apple number for the well used rates, I guess a computation would be needed for other things. Finally what about the default behaviour, would it be the old use a fixed setting or would we change the default to be automatic with the option of explicitly passing in 1000 to mimic the previous behaviour if required (plus any updates to fate to account for the change). Thanks Kevin _______________________________________________ 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".
