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

[pdr0]

Mark Filipak (ffmpeg) wrote
> 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.

The workaround is correct for the PTS

 AssumeFPS is used to change the frame rate (and timestamps) without
changing the frame count. It just assigns a framerate (and their PTS). So
you would use that instead of setpts

There are no frame drops or additions from vapoursynth. The framecount,
framerate and PTS are correct at that point. You can verify this by encoding
the vpy script directly without other filters. 

So this implies the some drops are from setpts, and some other drops are
from some of your other filters






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