Precompute a chroma_qp table with index offset for each pps,

this saves speed for the upcoming secondqp fix.
Patch by Andreas Öman % andreas A olebyn P nu %
Original thread:
Date: Jun 26, 2007 8:48 PM
subject: [FFmpeg-devel] Color corruption and seeking errors with H264 disc sources

Originally committed as revision 9498 to svn://svn.ffmpeg.org/ffmpeg/trunk