[FFmpeg-user] ffmpeg architecture question #2

pdr0 pdr0 at shaw.ca
Sat Apr 25 06:06:15 EEST 2020

Mark Filipak wrote
>> If you take a soft telecine input, encode it directly to rawvideo or
>> lossless output, you can confirm this.
>> The output is 29.97 (interlaced content) .
>>> When I do 'telecine=pattern=5', I wind up with this
>>> |<--------------------------1/6s-------------------------->|
>>> [A/a_][A/a_][A/b_][B/b_][B/b_][C/c_][C/c_][C/d_][D/d_][D/d_] 55-telecine
>>> I have confirmed it by single-frame stepping through test videos.
>> No.
> The above timing is for an MKV of the 55-telecine transcode, not for the
> decoder's output.

That's telecine=pattern=5 on a 23.976p native progressive source

I thought this thread was about using a soft telecine source , and how
ffmpeg handles that

because you were making assumptions "So, if the 'i30, TFF' from the decoder
is correct, the following must be the full picture: "

Obviously i30 does not refer to a 23.976p native progressive source...

>> Pattern looks correct, but unless you are doing something differently ,
>> your
>> timescale is not correct
>> When input is vob, mpeg2-ps or mpeg-es using soft telecine in my test,
>> using
>> telecine=pattern=5 the output frame rate is 74.925 as expected  (2.5 *
>> 29.97
>> = 74.925).
> Not for me. I've seen 74.925 FPS just one time. Since I considered it a
> failure, I didn't save the 
> video and its log, so I don't know how I got it.
>> This mean RF flags are used, 29.97i output from decoder. Since
>> its 74.925fps, the scale in your diagram for 1/6s is wrong for
>> telecine=pattern=5
> For this command line:
> ffmpeg -report -i "00001.018.m2ts" -filter_complex 
> "telecine=pattern=5,split=5[A][B][C][D][E],[A]select='eq(mod(n+1\,5)\,1)'[F],[B]select='eq(mod(n+1\,5)\,2)'[G],[C]select='eq(mod(n+1\,5)\,3)'[H],[D]select='eq(mod(n+1\,5)\,4)'[I],[E]select='eq(mod(n+1\,5)\,0)'[J],[F][G][H][I][J]interleave=nb_inputs=5" 
> -map 0 -c:v libx264 -crf 20 -codec:a copy -codec:s copy
> "C:\AVOut\00001.018.4.MKV"
> MPV playback of '00001.018.4.MKV' says "FPS: 59.940 (estimated)" (not
> 74.925fps).

Is that m2ts a soft telecine BD's ? This thread was about soft telecine...

Most film BD's are native progressive 23.976

>> Both ffplay and mpv look like they ignore the repeat field flags, the
>> preview is progressive 23.976p
> I use MPV. I'm unsure what you mean by "preview". ...and "preview" of
> what? The decoder output or 
> the MKV output video?

The "preview" of the video is what you see when ffplay window opens or mpv
opens. It's a RGB converted representation what you are using as input to
mpv or ffplay . So I'm referring to a soft telecine source, because that's
what you were talking about

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