[FFmpeg-devel] [PATCH] lavfi/buffersrc: push the frame deeper if requested.

[Paul B Mahol]

On 6/24/17, Michael Niedermayer <michael at niedermayer.cc> wrote:
> On Sat, Jun 24, 2017 at 04:54:38PM +0200, Michael Niedermayer wrote:
>> On Tue, Jun 20, 2017 at 07:59:26PM +0200, Paul B Mahol wrote:
>> > On 12/24/16, Nicolas George <george at nsup.org> wrote:
>> > > Le quartidi 4 nivose, an CCXXV, Michael Niedermayer a ecrit :
>> > >> theres a change with "-af apad=pad_len=10000 -shortest" (no
>> > >> -vframes)
>> > >> the file is not sharable, this change undoes the effect of the
>> > >> non-recursive patch
>> > >>
>> > >> use of vframes generally shows differences which seem to return to
>> > >> what
>> > >> things were before the "non recursive patch"
>> > >
>> > > Thanks for checking. Then I shall push shortly.
>> >
>> > This breaks :shortest=1 in all framesync filters, so I'm for reverting
>> > this.
>>
>> The revert broke alot
>> I would suggest to undo the revert and go through the normal review
>> process
>>
>> examples of breakages:
>> ./ffmpeg -i bgc.sub.dub.ogm -vframes 3 subs.webm
>>
>> (produces 1 instead of 3 frames in the output)
>>
>>
>> ./ffmpeg -i 2014-10-17\ 11.31\ i95Dev\ -\ Carlo\ Pazolini\ _\ KWI\ -\
>> Meeting.g2m  -max_muxing_queue_size 8000 -vframes 2 g2m5.avi
>>
>> fails:
>> [libmp3lame @ 0x3a5aee0] Queue input is backward in time
>> [avi @ 0x3a5e280] Too large number of skipped frames 194211 > 60000
>> 54.1kbits/s speed= 129x
>> av_interleaved_write_frame(): Invalid argument
>> [avi @ 0x3a5e280] Too large number of skipped frames 194111 > 60000
>> frame=    2 fps=1.1 q=2.0 Lsize=    1857kB time=00:03:14.35 bitrate=
>> 78.3kbits/s speed= 103x
>> video:149kB audio:1519kB subtitle:0kB other streams:0kB global headers:0kB
>> muxing overhead: 11.380948%
>> Conversion failed!
>> (iam not sure i can share this one)
>>
>>
>> ./ffmpeg -i ~/videos/matrixbench_mpeg2.mpg -vframes 20 -vcodec libx265
>> -omit_video_pes_length 0 -pix_fmt yuv420p file2.ts
>>
>> the change results in the aditional warnings on playback of the resulting
>> file:
>> [mpegts @ 0x3d10100] start time for stream 1 is not set in
>> estimate_timings_from_pts
>> [mpegts @ 0x3d10100] Could not find codec parameters for stream 1 (Audio:
>> mp3 ([3][0][0][0] / 0x0003), 0 channels, s16p): unspecified frame size
>> Consider increasing the value for the 'analyzeduration' and 'probesize'
>> options
>
> For some files the code as in git works better
>
> for example:
> ffmpeg -i
> ~/tickets/3872/MJ._.Hold.My.Hand._with.Akon__HEVC.1080p.Aex_A__1__001.mkv
> -vframes 4 file.avi
>
> produces a better matching audio stream length now

The reverted commit breaks lot of filters and I failed to find fix,
the only logical solution
was to revert commmit.

Also I'm not happy with current lavfi core state, its left in chaos.