[FFmpeg-user] Is there something about inputting raw frames

[Mark Filipak (ffmpeg)]

On 02/12/2021 01:27 AM, pdr0 wrote:
> Mark Filipak (ffmpeg) wrote
>> Is there something about inputting raw frames that I don't know?
>>
>> I'm using 'vspipe' to pipe raw frames to 'ffmpeg -i pipe:'.
>> The vapoursynth script, 'Mark's.vpy', is known good.
>> The output of vapoursynth is known good.
>> I've tried to be careful to retain valid PTSs, but apparently have failed.
>> The output should be around 1200 frames, but 364 frames are dropped.
>> I've frame stepped through the target, 'Mark's_script_6.mkv', and the
>> frames that are there are in
>> the correct order.
>> The only thing I can guess is that ffmpeg handles 48/1.001fps raw video
>> frames in such a way that
>> PTS is not valid or can't be changed with 'setpts=fps=60000/1001'.
>> Can anyone see an error. Or, lacking an error, does anyone know of a
>> workaround?
>>
>> Thanks.
>>
>> Mark's_script_6.cmd
>> =====
>> ECHO from vapoursynth import core>Mark's.vpy
>> ECHO video = core.ffms2.Source(source='Mark\'s_source.mkv')>>Mark's.vpy
>> ECHO import havsfunc as havsfunc>>Mark's.vpy
>> ECHO video = havsfunc.InterFrame(video, Preset="medium", Tuning="smooth",
>> InputType="2D",
>> NewNum=48000, NewDen=1001, GPU=True)>>Mark's.vpy
>> ECHO video.set_output()>>Mark's.vpy
>> vspipe --y4m Mark's.vpy - | ffmpeg -thread_queue_size 2048 -i pipe:
>> -filter_complex
>> "setpts=N*1001/60000/TB, split[1][2], [1]shuffleframes=0 1 2 3 3,
>> select=not(eq(mod(n\,5)\,4))[3],
>> [2]tblend=all_expr='if(eq(mod(X,2),mod(Y,2)),TOP,BOTTOM)', shuffleframes=0
>> 1 2 2 3,
>> select=eq(mod(n\,5)\,4)[4], [3][4]interleave" -i Mark's_source.mkv -map
>> 0:v -map 1:a -codec:v
>> libx265 -x265-params "crf=16:qcomp=0.60" -codec:a copy -codec:s copy
>> Mark's_script_6.mkv -y
> 
> 
> Are you trying to keep the same frames from vapoursynth output node, but
> assign 60000/1001 fps and timestamps instead of 48000/1001 ? (effectively
> making it a speed up)
> 
> If so, the workaround is : add after the Interframe line
> 
> video = core.std.AssumeFPS(video, fpsnum=60000, fpsden=1001)

After your suggested addition to the python script, Mark's.vpy,
With '-filter_complex "setpts=N*1001/60000/TB, split[1][2]...' there are 335 drops.
With '-filter_complex "split[1][2]...' there are 190 drops.

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