I'm trying to get information about frames in h264 bitstream. Especially motion vectors of macroblocks. I think, I have to use ffmpeg code for it, but it's really huge and hard to understand. So, can someone give me some tips or exapmles of partial decoding from raw data of single frame from h264 stream?
Thank you.
Unfortunately, to get that level of information from the bitstream you have to decode every macroblock, there's no quick option, like there would be for getting information from the slice header.
One option is to use the h.264 reference software and turn on the verbose debug output and/or add your own printf's where needed, but this is also a large code base to navigate:
http://iphome.hhi.de/suehring/tml/
(You can also use ffmpeg and add output where needed too as you said, but it would take some understanding of that code base too)
There are graphical tools for analyzing video bitstreams which will show you this type of information on a per-macroblock basis, many are expensive, but sometimes there are free trial versions available.
