From 19fb234e4af1ff9f58ff2fdd604ac6f6bb87ad6b Mon Sep 17 00:00:00 2001 From: Jason Garrett-Glaser Date: Fri, 14 Jan 2011 21:34:25 +0000 Subject: H.264: split luma dc idct out and implement MMX/SSE2 versions About 2.5x the speed. NOTE: the way that the asm code handles large qmuls is a bit suboptimal. If x264-style dequant was used (separate shift and qmul values), it might be possible to get some extra speed. Originally committed as revision 26336 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/h264idct.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'libavcodec/h264idct.c') diff --git a/libavcodec/h264idct.c b/libavcodec/h264idct.c index 86c5ef2559..f5b05ac24f 100644 --- a/libavcodec/h264idct.c +++ b/libavcodec/h264idct.c @@ -216,3 +216,38 @@ void ff_h264_idct_add8_c(uint8_t **dest, const int *block_offset, DCTELEM *block ff_h264_idct_dc_add_c(dest[(i&4)>>2] + block_offset[i], block + i*16, stride); } } +/** + * IDCT transforms the 16 dc values and dequantizes them. + * @param qp quantization parameter + */ +void ff_h264_luma_dc_dequant_idct_c(DCTELEM *output, DCTELEM *input, int qmul){ +#define stride 16 + int i; + int temp[16]; + static const uint8_t x_offset[4]={0, 2*stride, 8*stride, 10*stride}; + + for(i=0; i<4; i++){ + const int z0= input[4*i+0] + input[4*i+1]; + const int z1= input[4*i+0] - input[4*i+1]; + const int z2= input[4*i+2] - input[4*i+3]; + const int z3= input[4*i+2] + input[4*i+3]; + + temp[4*i+0]= z0+z3; + temp[4*i+1]= z0-z3; + temp[4*i+2]= z1-z2; + temp[4*i+3]= z1+z2; + } + + for(i=0; i<4; i++){ + const int offset= x_offset[i]; + const int z0= temp[4*0+i] + temp[4*2+i]; + const int z1= temp[4*0+i] - temp[4*2+i]; + const int z2= temp[4*1+i] - temp[4*3+i]; + const int z3= temp[4*1+i] + temp[4*3+i]; + + output[stride* 0+offset]= ((((z0 + z3)*qmul + 128 ) >> 8)); + output[stride* 1+offset]= ((((z1 + z2)*qmul + 128 ) >> 8)); + output[stride* 4+offset]= ((((z1 - z2)*qmul + 128 ) >> 8)); + output[stride* 5+offset]= ((((z0 - z3)*qmul + 128 ) >> 8)); + } +} -- cgit v1.2.3