[FFmpeg-devel] [PATCH] Add new MPEG bitstream filter

Mark Thompson sw at jkqxz.net
Tue Aug 1 22:59:23 EEST 2017

On 01/08/17 19:05, Jan Ekstrom wrote:
> Hi,
> On Tue, Aug 1, 2017 at 3:22 PM, David Griffiths
> <david.griffiths at gmail.com> wrote:
>> Given an MPEG1/2 stream, this bitstream filter can be used to modify
>> the sequence headers. The most common use would be to change the
>> aspect ration without the need for re-encoding. Some MOD files have
>> the aspect ratio incorrectly set to 4:3
>> (see https://en.wikipedia.org/wiki/MOD_and_TOD).
> Thanks for the contribution, but this looks like a limited version of
> https://lists.libav.org/pipermail/libav-devel/2017-July/084528.html ,
> which seems to contain support for MPEG-2 bit stream filtering as
> well.
I'm intending to bring this across myself soon.  It's slightly awkward because it's all written against Alexandra's bitstream API and would need to be changed to get_bits here.  (I was hoping the API would come at some point, but apparently people here are generally against it.  Oh well.)

Anyway, I finished off a half-written MPEG-2 metadata filter which will do the stuff described here: <https://lists.libav.org/pipermail/libav-devel/2017-August/084563.html>.  I've ignored MPEG-1 so far, but it would probably be easy to add if anyone cares.

- Mark

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