I want to implement LSB-steganography algorithm for h264-encoded video. According to this paper <http://www.cs.ox.ac.uk/andrew.ker/docs/ADK54B.pdf> , I need to modify the quantized coefficients in encoder, and translate video (via vlc-media player).
The quality of the encoded video went bad and some steganography artifacts occured in destination video player. Now I want to extract hidden information, but I can't find a place in libav codec, where decoder gets the DCT coefficients. I checked the function *decode_cabac_residual_internal()* in *h264_cabac.c* and dumped *block[]* of some coefficients there, but it differs from coefficients , I dumped in encoder. Where is the place in decoder, where I can get dct coefficients, that i sent from encoder? Thanks, Nj -- View this message in context: http://libav-users.943685.n4.nabble.com/Libav-user-h264-getting-dct-coefficients-in-decoder-tp4662187.html Sent from the libav-users mailing list archive at Nabble.com. _______________________________________________ Libav-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/libav-user
