[FFmpeg-user] telecine pattern 5555 - Judder-free, 60 FPS telecine (?)

Paul B Mahol onemda at gmail.com
Mon Mar 30 12:09:18 EEST 2020


On 3/30/20, Mark Filipak <markfilipak.windows+ffmpeg at gmail.com> wrote:
> Howdy,
>
> In order to make my 5-5-5-5 pull-down, anti-judder trick work with soft
> telecined content (see
> Details, below), I reckon I need to rewrite the 'frame_rate_code' nibble
> found in the MPEG PGC's
> SEQUENCE_HEADER (i.e., 0x000001B3), at offset = 7, bits 4-7 (big endian). I
> need to change bits 4-7
> from '0100' (i.e., 30/1.001 FPS) to '0001' (i.e., 24/1.001 FPS).
>
> Do you have any ideas how/whether ffmpeg can do this?
>
> Details:
> The "telecine=pattern=5555" filter appears to look at 'frame_rate_code'.
> Since, for soft-telecined
> content, 'frame_rate_code' is set to '0100' (i.e., 30/1.001 -- which is
> bogus), the 'telecine'
> filter miscalculates PTS times and the resulting OUT.MKV runs fast (though
> audio is not affected).
> The target PTS times should be 20/8*(24/1.001) because the *actual* frames
> are at 24/1.001 FPS --
> it's soft telecined! But because 'frame_rate_code' is set to '0100',
> 'telecine' instead calculates
> PTS times as 20/8*(30/1.001). So, instead of being made at 60/1.001 FPS,
> OUT.MKV is made at 75/1.001
> FPS.
>
> Thanks for any help/insight you can provide (and I'm sorry this is so
> obscure, but a rewrite fix of
> the source video is probably easier than trying to get the developers to
> modify 'telecine').

You do not know what you are doing.
Also soft-telecine is not supported.


>
> Regards,
> Mark.
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