[Ffmpeg-devel] libavcodec h264 decoder

michael benzon chua chibiakaii
Thu Dec 14 17:41:05 CET 2006

apologies if this post isn't in any particular format, i couldn't find
anything on the mailing list page about following a specific protocol.

can someone point me to where libavcodec decodes h.264 macroblocks? im
trying to access the dct coefficients of i type 4x4 luma blocks.

essentially, i modified the x264 encoder to flip the sign of the top-left
most coefficient in the dct block during macroblock encoding, and i want to
try and reverse the process during decoding. i just added this line of code
in x264's encoder/macroblock.c, under the x264_mb_encode_i4x4 function:

dct4x4[0][0] = 0 - dct4x4[0][0];

right after quantization and scanning, but before dequantization...

i'm having trouble tracing the libavcodec source to the function that
decodes h264 macroblocks... i'm assuming this is somewhere in
libavcodec/h264.c or libavcodec/h264idct.c

can anyone help me? thanks...

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