[Ffmpeg-devel] libavcodec h264 decoder

[Stefan Gehrer]

michael benzon chua wrote:
> 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.

In h264.c, functions decode_mb_cavlc and decode_mb_cabac.

>
> 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...
>
What are you trying to achieve with that?

Stefan