On Thu, Jul 23, 2009 at 3:17 AM, Alessandro Ferrari <[email protected]> wrote: > > Hello dear community, > in your opinion, I can use ffmpeg library > for parsing an encoded h.264 p-frame to extract Macroblocks and Motion > prediction Vectors Information? My target is to transcoding an h264 stream > for reducing bitrate by reduce granularity of the DCT coefficient, and for > achieve this i want to first extract information by the original encoded > stream, decode the stream, and then encoding the stream without recalculate > the motion prediction information. > Thank in advance for your attention.
Take a look at the MV visualization code in ff_print_debug_info of mpegvideo.c. I'm doing the same thing right now, and it involves a lot of hackery. You can calculate MVs through motion_val field of avframe, but to be useful you also need the MB info, which is tucked tucked away in the mpegenccontext field of h264context, neither of which are available via the public API (afaik). Right now I basically #include h264.h which is really messy. If there is a better way of doing this I'd like to hear it. _______________________________________________ libav-user mailing list [email protected] https://lists.mplayerhq.hu/mailman/listinfo/libav-user
