h264idct.c
资源名称:X264CODEC.rar [点击查看]
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上传日期:2022-06-04
资源大小:8887k
文件大小:6k
源码类别:
流媒体/Mpeg4/MP4
开发平台:
Visual C++
- /*
- * H.264 IDCT
- * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
- *
- * This file is part of FFmpeg.
- *
- * FFmpeg is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * FFmpeg is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
- /**
- * @file h264-idct.c
- * H.264 IDCT.
- * @author Michael Niedermayer <michaelni@gmx.at>
- */
- #include "dsputil.h"
- static av_always_inline void idct_internal(uint8_t *dst, DCTELEM *block, int stride, int block_stride, int shift, int add){
- int i;
- uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
- block[0] += 1<<(shift-1);
- for(i=0; i<4; i++){
- const int z0= block[0 + block_stride*i] + block[2 + block_stride*i];
- const int z1= block[0 + block_stride*i] - block[2 + block_stride*i];
- const int z2= (block[1 + block_stride*i]>>1) - block[3 + block_stride*i];
- const int z3= block[1 + block_stride*i] + (block[3 + block_stride*i]>>1);
- block[0 + block_stride*i]= z0 + z3;
- block[1 + block_stride*i]= z1 + z2;
- block[2 + block_stride*i]= z1 - z2;
- block[3 + block_stride*i]= z0 - z3;
- }
- for(i=0; i<4; i++){
- const int z0= block[i + block_stride*0] + block[i + block_stride*2];
- const int z1= block[i + block_stride*0] - block[i + block_stride*2];
- const int z2= (block[i + block_stride*1]>>1) - block[i + block_stride*3];
- const int z3= block[i + block_stride*1] + (block[i + block_stride*3]>>1);
- dst[i + 0*stride]= cm[ add*dst[i + 0*stride] + ((z0 + z3) >> shift) ];
- dst[i + 1*stride]= cm[ add*dst[i + 1*stride] + ((z1 + z2) >> shift) ];
- dst[i + 2*stride]= cm[ add*dst[i + 2*stride] + ((z1 - z2) >> shift) ];
- dst[i + 3*stride]= cm[ add*dst[i + 3*stride] + ((z0 - z3) >> shift) ];
- }
- }
- void ff_h264_idct_add_c(uint8_t *dst, DCTELEM *block, int stride){
- idct_internal(dst, block, stride, 4, 6, 1);
- }
- void ff_h264_lowres_idct_add_c(uint8_t *dst, int stride, DCTELEM *block){
- idct_internal(dst, block, stride, 8, 3, 1);
- }
- void ff_h264_lowres_idct_put_c(uint8_t *dst, int stride, DCTELEM *block){
- idct_internal(dst, block, stride, 8, 3, 0);
- }
- void ff_h264_idct8_add_c(uint8_t *dst, DCTELEM *block, int stride){
- int i;
- DCTELEM (*src)[8] = (DCTELEM(*)[8])block;
- uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
- block[0] += 32;
- for( i = 0; i < 8; i++ )
- {
- const int a0 = src[i][0] + src[i][4];
- const int a2 = src[i][0] - src[i][4];
- const int a4 = (src[i][2]>>1) - src[i][6];
- const int a6 = (src[i][6]>>1) + src[i][2];
- const int b0 = a0 + a6;
- const int b2 = a2 + a4;
- const int b4 = a2 - a4;
- const int b6 = a0 - a6;
- const int a1 = -src[i][3] + src[i][5] - src[i][7] - (src[i][7]>>1);
- const int a3 = src[i][1] + src[i][7] - src[i][3] - (src[i][3]>>1);
- const int a5 = -src[i][1] + src[i][7] + src[i][5] + (src[i][5]>>1);
- const int a7 = src[i][3] + src[i][5] + src[i][1] + (src[i][1]>>1);
- const int b1 = (a7>>2) + a1;
- const int b3 = a3 + (a5>>2);
- const int b5 = (a3>>2) - a5;
- const int b7 = a7 - (a1>>2);
- src[i][0] = b0 + b7;
- src[i][7] = b0 - b7;
- src[i][1] = b2 + b5;
- src[i][6] = b2 - b5;
- src[i][2] = b4 + b3;
- src[i][5] = b4 - b3;
- src[i][3] = b6 + b1;
- src[i][4] = b6 - b1;
- }
- for( i = 0; i < 8; i++ )
- {
- const int a0 = src[0][i] + src[4][i];
- const int a2 = src[0][i] - src[4][i];
- const int a4 = (src[2][i]>>1) - src[6][i];
- const int a6 = (src[6][i]>>1) + src[2][i];
- const int b0 = a0 + a6;
- const int b2 = a2 + a4;
- const int b4 = a2 - a4;
- const int b6 = a0 - a6;
- const int a1 = -src[3][i] + src[5][i] - src[7][i] - (src[7][i]>>1);
- const int a3 = src[1][i] + src[7][i] - src[3][i] - (src[3][i]>>1);
- const int a5 = -src[1][i] + src[7][i] + src[5][i] + (src[5][i]>>1);
- const int a7 = src[3][i] + src[5][i] + src[1][i] + (src[1][i]>>1);
- const int b1 = (a7>>2) + a1;
- const int b3 = a3 + (a5>>2);
- const int b5 = (a3>>2) - a5;
- const int b7 = a7 - (a1>>2);
- dst[i + 0*stride] = cm[ dst[i + 0*stride] + ((b0 + b7) >> 6) ];
- dst[i + 1*stride] = cm[ dst[i + 1*stride] + ((b2 + b5) >> 6) ];
- dst[i + 2*stride] = cm[ dst[i + 2*stride] + ((b4 + b3) >> 6) ];
- dst[i + 3*stride] = cm[ dst[i + 3*stride] + ((b6 + b1) >> 6) ];
- dst[i + 4*stride] = cm[ dst[i + 4*stride] + ((b6 - b1) >> 6) ];
- dst[i + 5*stride] = cm[ dst[i + 5*stride] + ((b4 - b3) >> 6) ];
- dst[i + 6*stride] = cm[ dst[i + 6*stride] + ((b2 - b5) >> 6) ];
- 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 = ff_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 = ff_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;
- }
- }