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

[pdr0]

Mark Filipak (ffmpeg) wrote
> On 02/12/2021 02:28 AM, pdr0 wrote:
>> 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
> 
> Well, I previously removed the 'setpts' directives with no change. Also, I
> previously tested with no 
> ffmpeg filters at all and got the expected sped up video. I honestly can't
> see anything else to 
> discover. But I'll start stripping filters one by one and hack a solution
> (or make a discovery). Of 
> course, the 'shuffleframes' directives are most suspect, but I've used
> 'shuffleframes' in the past 
> and succeeded.
> 
> Thanks for your help. It was instrumental. The rest is up to me.




I realize this is ffmpeg-user board, but why not do some of the video
processing in vapoursynth ? You're already using it for part of it.  But I'm
not sure what you're trying to do ?

It looks like you're taking the 48000/1001 interpolated frame doubled output
and adding a "BC~C.bc~c" frame to every group of 4, to make up the
60000/1001? 

What is a "BC~C.bc~c" frame ? Is it that checkerboard blend?
http://ffmpeg.org/pipermail/ffmpeg-user/2021-February/051852.html

Either way, cadence wise that's going to be worse in terms of smoothness
then an optical flow retimed 60000/1001 . (Some people would argue it's
worse period, you're retiming it and making it look like a soap opera...)

Are you actually interested in workarounds and getting the job done, or just
how to do this in ffmpeg?

If you just want it done, this is easier in avisynth because of the
InterleaveEvery function;
http://avisynth.nl/index.php/ApplyEvery#InterleaveEvery

And InterleaveEvery works on frames , not timestamps. It should be possible
in vapoursynth too, but vapoursynth doesn't have that exact function neatly
wrapped up already, you'd have to cobble together some python, a quick vpy
solution doesn't come to my mind






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