telecine pattern 5555 - Judder-free, 60 FPS telecine (?)

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telecine pattern 5555 - Judder-free, 60 FPS telecine (?)

Mark Filipak
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').

Regards,
Mark.
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Re: telecine pattern 5555 - Judder-free, 60 FPS telecine (?)

Paul B Mahol
On 3/30/20, Mark Filipak <[hidden email]> 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.
> _______________________________________________
> ffmpeg-user mailing list
> [hidden email]
> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> [hidden email] with subject "unsubscribe".
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Re: telecine pattern 5555 - Judder-free, 60 FPS telecine (?)

Mark Filipak
> You do not know what you are doing.

What part are you not understanding?

> Also soft-telecine is not supported.

I'm not trying to soft telecine the output (OUT.MKV). The input (IN.M2TS) is soft telecined -- it's
a DVD movie -- so that's what I have to deal with.

Would you like an overview of what I've accomplished and what I want to further accomplish and why
it's important?

Regards,
Mark.


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Re: telecine pattern 5555 - Judder-free, 60 FPS telecine (?)

Mark Filipak
In reply to this post by Paul B Mahol
Sorry, correction...

> You do not know what you are doing.

What part are you not understanding?

> Also soft-telecine is not supported.

I'm not trying to soft telecine the output (OUT.MKV). The input (IN.VOB) is soft telecined -- it's a
DVD movie -- so that's what I have to deal with.

Would you like an overview of what I've accomplished and what I want to further accomplish and why
it's important?

Regards,
Mark.


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