From ef9d1d15751c6a2e4c570727c198854ce8b44603 Mon Sep 17 00:00:00 2001 From: Loren Merritt Date: Fri, 10 Feb 2006 06:55:25 +0000 Subject: h264: special case dc-only idct. ~1% faster overall Originally committed as revision 4971 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/h264idct.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'libavcodec/h264idct.c') diff --git a/libavcodec/h264idct.c b/libavcodec/h264idct.c index a4ddf1d51d..3e44385d5e 100644 --- a/libavcodec/h264idct.c +++ b/libavcodec/h264idct.c @@ -139,3 +139,28 @@ void ff_h264_idct8_add_c(uint8_t *dst, DCTELEM *block, int stride){ dst[i + 7*stride] = cm[ dst[i + 7*stride] + ((b0 - b7) >> 6) ]; } } + +// assumes all AC coefs are 0 +void ff_h264_idct_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){ + int i, j; + uint8_t *cm = cropTbl + MAX_NEG_CROP; + int dc = (block[0] + 32) >> 6; + for( j = 0; j < 4; j++ ) + { + for( i = 0; i < 4; i++ ) + dst[i] = cm[ dst[i] + dc ]; + dst += stride; + } +} + +void ff_h264_idct8_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){ + int i, j; + uint8_t *cm = cropTbl + MAX_NEG_CROP; + int dc = (block[0] + 32) >> 6; + for( j = 0; j < 8; j++ ) + { + for( i = 0; i < 8; i++ ) + dst[i] = cm[ dst[i] + dc ]; + dst += stride; + } +} -- cgit v1.2.3