[FFmpeg-user] Unresolved concatenation and subtitle problems

Mark Filipak markfilipak.imdb at gmail.com
Mon Jan 1 04:25:35 EET 2024


This is 00305+00306.mkv_framecrc.txt.
It is headed by this analysis of the concatenation of 00305.mkv & 00306.mkv.

00305+00306.mkv contains either 241520 or 241552 or 241554 frames.
The differences cannot be explained away as rounding differences.

00305+00306.mkv has a span of 1188892 packets:
• 944567 audio packets PTS=0..10075411.
   48000 samp-per-sec, 483618304 samples, 512 samp-per-pack.
• 2782 subtitle packets PTS=54295..10073292.
• 241543 video packets PTS=617..10075378.
   • That's 617.5±0.4[9..]..10075378.5±0.4[9..]
          = 10074761±0.9[9..] video ticks, exactly.
          = 241552.[711288..]±0.[023976..] frames, exactly.
   • '-showinfo' reports N=0..241519 = 241520 frames.
   • MPV shows 0.617..2:47:55.460 end to end
     = 0.6175±0.0004[9..]..2:47:55.4605±0.0004[9..]
     = 10074843.0±0.9[9..] ticks, exactly.
     = 241554.[677322..]±0.[023976..] frames, exactly.

So, are there
   241520 frames, as '-showinfo' claims, or
   241552 frames, as '-framecrc' claims, or
   241554 frames, as MPV shows?
I favor 241552 as '-framecrc' claims for no particular reason.

I will post 00305+00306.mkv_framecrc.txt on request. It is 70 MB.
I will post 00305+00306.mkv_showinfo.txt on request. It is 124 MB.

No, I cannot assume '-framecrc' is correct.

In the face of inconsistent FFmpeg tools, I'm giving up.

-- Mark.


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