[FFmpeg-devel] [PATCH]lavc: Allow forcing work-around for x264 cabac 8x8 4:4:4 bug

[Carl Eugen Hoyos]

2017-12-04 1:56 GMT+01:00 Mark Thompson <sw at jkqxz.net>:
> On 04/12/17 00:09, Carl Eugen Hoyos wrote:

>> Attached patch fixes ticket #6717, files without sei can be produced
>> with remuxing and seeking, even if this is a (separate) bug, such
>> files exist in the wild.

> File are currently fixable by remuxing with:
>
> -bsf:v 'h264_metadata=sei_user_data=dc45e9bde6d948b7962cd820d923eeef+x264 - core 150'

Thank you!

> Unfortunately that can't be applied directly when decoding,
> because -bsf isn't available as an input option.

> I don't really like the idea of adding the option because it does
> break correct files, but I guess it probably ends up being the
> pragmatic option for decoding.

Sorry, I don't understand: Do you mean if the user specifies
the work-around, it will break files encoded with current
x264? Isn't that the whole point of this (and every other)
work-around?

> Still, I think it might be sensible to at least add a big warning
> telling the user they're doing something stupid if this option
> is set and it finds x264_build is >= 151?

I believe you know that I am a big fan of warnings but printing
a warning when a user explicitely specifies an option? We
don't warn when an experimental encoder is used (not even
when we know it will segfault) and I don't think it is necessary.

Thank you, Carl Eugen