[FFmpeg-devel] [PATCH] Added support for MB_INFO

[Anton Khirnov]

Quoting Carotti, Elias (2022-06-21 10:48:07)
> Hi,
> 
> extending AVVideoEncParams was the first hypothesis I made but it
> didn't seem it was the proper place to add the mb_info flags.
> 
> I may be wrong but my impression is that AVVideoEncParams is used to
> carry encoding parameters read from the bitstream at the decoder side
> while here were going the other direction, i.e., were passing
> information from the application to the encoder.
> 
> Secondly, mb_info can't be strictly considered encoding parameters and
> it's not present in the bitstream at all. 
> It's just a way to give hints to the libx264 encoder on which
> macroblock we know have not changed since the previous frame and could
> be coded as P_SKIPs. Libx264 however, may or may not oblige according
> to its logic, and this specific information is not transmitted in the
> bitstream nor can be recovered at the decoder.

Right, seems I was too hasty in reading your patch.

But then I have to wonder whether this really needs a new installed
header, with a struct and a destructor, given that it's specific to a
single encoder for a single codec that is about 20 years old now.

Wouldn't AV_FRAME_DATA_X264_MBINFO that would be just a raw array of
uint8_t serve your needs just as fine? You could even get custom buffer
management by using AVFrameSideData.buf.

-- 
Anton Khirnov