On 3/10/18, Jan Ekstroem <jee...@gmail.com> wrote: > Hi, > > I would like to raise a question regarding how the community feels > about removing hacks which most likely were done to work around > deficiencies of API clients. Silently. > > Some weeks ago someone asked on #ffmpeg why he wasn't getting the time > scale (time base in MOV/ISOBMFF speak) he wanted out of movenc.c. So I > looked into it: > > 1) > https://git.videolan.org/?p=ffmpeg.git;a=commit;h=b02493e47668e66757b72a7163476e590edfea3a > (2012) Some API clients didn't clearly set a time base correctly for > VFR content - a hack was added in movenc.c to bump the time scale to > at least 10k. > 2) https://git.videolan.org/?p=ffmpeg.git;a=commit;h=7e570f027b9bb0b5504 > ed443c70ceb654930859d > (2013) Someone clearly didn't like this forced behavior so an > AVOption was added to set a forced video time base for ALL video > tracks in a mux. > 3) > https://git.videolan.org/?p=ffmpeg.git;a=commit;h=194be1f43ea391eb986732707435176e579265aa > (2014) Anton switches the time base utilized from the encoder > AVCodec to the AVStream, which most likely fixes the issue of output > time base being incorrect as some encoders dislike weird (?) time > bases (although how would you get VFR content through those if that > was the reason is still beyond me). > > After this I told the user that this is a hack that's been added and > that his timestamps are still exact (which they are, just that the > time base is larger than it is). But as a developer, this just looks > like the whole mess should be removed: > > 1) ffmpeg.c , for which the original hack possibly was added in 2012, > now has an option to set output time base as far as I can remember? So > the user of the tool can properly set a specific time base if > required, just like with the AVOption. > 2) This is just extra complexity/automated logic that can be hiding > bugs in API clients, and we ended up having an additional AVOption. > > So, going forward, would patches to remove things like these be worth > sending to the list?
I'm all for exposing all hacks and removing all of them from the FFmpeg codebase. > > > Best regards, > Jan Ekstroem > _______________________________________________ > 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
