PeerStreamer

/*

 * 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));

    }

#undef stride

}

void ff_h264_chroma_dc_dequant_idct_c(DCTELEM *block, int qmul){

    const int stride= 16*2;

    const int xStride= 16;

    int a,b,c,d,e;

    a= block[stride*0 + xStride*0];

    b= block[stride*0 + xStride*1];

    c= block[stride*1 + xStride*0];

    d= block[stride*1 + xStride*1];

    e= a-b;

    a= a+b;

    b= c-d;

    c= c+d;

    block[stride*0 + xStride*0]= ((a+c)*qmul) >> 7;

    block[stride*0 + xStride*1]= ((e+b)*qmul) >> 7;

    block[stride*1 + xStride*0]= ((a-c)*qmul) >> 7;

    block[stride*1 + xStride*1]= ((e-b)*qmul) >> 7;

}