[FFmpeg-devel] AVFilter for watermarking DCTELEM MPEG2 blocks

[Roger Pau Monné]

Hello,

I've done a modification to the ffmpeg source code, to add a watermark
in MPEG2 DCTELEM luminance blocks (modifying the
MPV_decode_mb_internal function), and now I would like to convert it
to a plugin, so it can be used with other versions of ffmpeg without
having to modify the source code. I've took a look at the Libavfilter
documentation, but I think it only allows you to modify pixels in a
frame, what I'm looking for is some kind of hook for
MPV_decode_mb_internal function, that is found in the
libavcodec/mpegvideo.c, so that I have access to the DCTELEM
block[12][64] parameter passed to this function. Is there anyway to do
this?

My english is not very good, so I don't know if the explanation of the
problem is as accurate as it should be, if you need more info about
the issue don't hesitate to ask it.

Thanks, Roger.