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FFmpeg/libavcodec/h264idct.c

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/*
* 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
* 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[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);
block[i + block_stride*0]= z0 + z3;
block[i + block_stride*1]= z1 + z2;
block[i + block_stride*2]= z1 - z2;
block[i + block_stride*3]= z0 - z3;
}
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);
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;
uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
block[0] += 32;
for( i = 0; i < 8; i++ )
{
const int a0 = block[i+0*8] + block[i+4*8];
const int a2 = block[i+0*8] - block[i+4*8];
const int a4 = (block[i+2*8]>>1) - block[i+6*8];
const int a6 = (block[i+6*8]>>1) + block[i+2*8];
const int b0 = a0 + a6;
const int b2 = a2 + a4;
const int b4 = a2 - a4;
const int b6 = a0 - a6;
const int a1 = -block[i+3*8] + block[i+5*8] - block[i+7*8] - (block[i+7*8]>>1);
const int a3 = block[i+1*8] + block[i+7*8] - block[i+3*8] - (block[i+3*8]>>1);
const int a5 = -block[i+1*8] + block[i+7*8] + block[i+5*8] + (block[i+5*8]>>1);
const int a7 = block[i+3*8] + block[i+5*8] + block[i+1*8] + (block[i+1*8]>>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);
block[i+0*8] = b0 + b7;
block[i+7*8] = b0 - b7;
block[i+1*8] = b2 + b5;
block[i+6*8] = b2 - b5;
block[i+2*8] = b4 + b3;
block[i+5*8] = b4 - b3;
block[i+3*8] = b6 + b1;
block[i+4*8] = b6 - b1;
}
for( i = 0; i < 8; i++ )
{
const int a0 = block[0+i*8] + block[4+i*8];
const int a2 = block[0+i*8] - block[4+i*8];
const int a4 = (block[2+i*8]>>1) - block[6+i*8];
const int a6 = (block[6+i*8]>>1) + block[2+i*8];
const int b0 = a0 + a6;
const int b2 = a2 + a4;
const int b4 = a2 - a4;
const int b6 = a0 - a6;
const int a1 = -block[3+i*8] + block[5+i*8] - block[7+i*8] - (block[7+i*8]>>1);
const int a3 = block[1+i*8] + block[7+i*8] - block[3+i*8] - (block[3+i*8]>>1);
const int a5 = -block[1+i*8] + block[7+i*8] + block[5+i*8] + (block[5+i*8]>>1);
const int a7 = block[3+i*8] + block[5+i*8] + block[1+i*8] + (block[1+i*8]>>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;
int dc = (block[0] + 32) >> 6;
uint8_t *cm = ff_cropTbl + MAX_NEG_CROP + dc;
for( j = 0; j < 4; j++ )
{
for( i = 0; i < 4; i++ )
dst[i] = cm[ dst[i] ];
dst += stride;
}
}
void ff_h264_idct8_dc_add_c(uint8_t *dst, DCTELEM *block, int stride){
int i, j;
int dc = (block[0] + 32) >> 6;
uint8_t *cm = ff_cropTbl + MAX_NEG_CROP + dc;
for( j = 0; j < 8; j++ )
{
for( i = 0; i < 8; i++ )
dst[i] = cm[ dst[i] ];
dst += stride;
}
}
//FIXME this table is a duplicate from h264data.h, and will be removed once the tables from, h264 have been split
static const uint8_t scan8[16 + 2*4]={
4+1*8, 5+1*8, 4+2*8, 5+2*8,
6+1*8, 7+1*8, 6+2*8, 7+2*8,
4+3*8, 5+3*8, 4+4*8, 5+4*8,
6+3*8, 7+3*8, 6+4*8, 7+4*8,
1+1*8, 2+1*8,
1+2*8, 2+2*8,
1+4*8, 2+4*8,
1+5*8, 2+5*8,
};
void ff_h264_idct_add16_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
int i;
for(i=0; i<16; i++){
int nnz = nnzc[ scan8[i] ];
if(nnz){
if(nnz==1 && block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
else idct_internal (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
}
}
}
void ff_h264_idct_add16intra_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
int i;
for(i=0; i<16; i++){
if(nnzc[ scan8[i] ]) idct_internal (dst + block_offset[i], block + i*16, stride, 4, 6, 1);
else if(block[i*16]) ff_h264_idct_dc_add_c(dst + block_offset[i], block + i*16, stride);
}
}
void ff_h264_idct8_add4_c(uint8_t *dst, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
int i;
for(i=0; i<16; i+=4){
int nnz = nnzc[ scan8[i] ];
if(nnz){
if(nnz==1 && block[i*16]) ff_h264_idct8_dc_add_c(dst + block_offset[i], block + i*16, stride);
else ff_h264_idct8_add_c (dst + block_offset[i], block + i*16, stride);
}
}
}
void ff_h264_idct_add8_c(uint8_t **dest, const int *block_offset, DCTELEM *block, int stride, const uint8_t nnzc[6*8]){
int i;
for(i=16; i<16+8; i++){
if(nnzc[ scan8[i] ])
ff_h264_idct_add_c (dest[(i&4)>>2] + block_offset[i], block + i*16, stride);
else if(block[i*16])
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));
}
}