FFmpeg/libavcodec/binkidct.c

/*
 * Bink IDCT algorithm
 * Copyright (c) 2009 Kostya Shishkov
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Bink IDCT algorithm
 */

#include "dsputil.h"

#define A1  2896 /* (1/sqrt(2))<<12 */
#define A2  2217
#define A3  3784
#define A4 -5352

#define IDCT_TRANSFORM(dest,s0,s1,s2,s3,s4,s5,s6,s7,d0,d1,d2,d3,d4,d5,d6,d7,munge,src) {\
    const int a0 = (src)[s0] + (src)[s4]; \
    const int a1 = (src)[s0] - (src)[s4]; \
    const int a2 = (src)[s2] + (src)[s6]; \
    const int a3 = (A1*((src)[s2] - (src)[s6])) >> 11; \
    const int a4 = (src)[s5] + (src)[s3]; \
    const int a5 = (src)[s5] - (src)[s3]; \
    const int a6 = (src)[s1] + (src)[s7]; \
    const int a7 = (src)[s1] - (src)[s7]; \
    const int b0 = a4 + a6; \
    const int b1 = (A3*(a5 + a7)) >> 11; \
    const int b2 = ((A4*a5) >> 11) - b0 + b1; \
    const int b3 = (A1*(a6 - a4) >> 11) - b2; \
    const int b4 = ((A2*a7) >> 11) + b3 - b1; \
    (dest)[d0] = munge(a0+a2   +b0); \
    (dest)[d1] = munge(a1+a3-a2+b2); \
    (dest)[d2] = munge(a1-a3+a2+b3); \
    (dest)[d3] = munge(a0-a2   -b4); \
    (dest)[d4] = munge(a0-a2   +b4); \
    (dest)[d5] = munge(a1-a3+a2-b3); \
    (dest)[d6] = munge(a1+a3-a2-b2); \
    (dest)[d7] = munge(a0+a2   -b0); \
}
/* end IDCT_TRANSFORM macro */

#define MUNGE_NONE(x) (x)
#define IDCT_COL(dest,src) IDCT_TRANSFORM(dest,0,8,16,24,32,40,48,56,0,8,16,24,32,40,48,56,MUNGE_NONE,src)

#define MUNGE_ROW(x) (((x) + 0x7F)>>8)
#define IDCT_ROW(dest,src) IDCT_TRANSFORM(dest,0,1,2,3,4,5,6,7,0,1,2,3,4,5,6,7,MUNGE_ROW,src)

static inline void bink_idct_col(int *dest, const DCTELEM *src)
{
    if ((src[8]|src[16]|src[24]|src[32]|src[40]|src[48]|src[56])==0) {
        dest[0]  =
        dest[8]  =
        dest[16] =
        dest[24] =
        dest[32] =
        dest[40] =
        dest[48] =
        dest[56] = src[0];
    } else {
        IDCT_COL(dest, src);
    }
}

void ff_bink_idct_c(DCTELEM *block)
{
    int i;
    int temp[64];

    for (i = 0; i < 8; i++)
        bink_idct_col(&temp[i], &block[i]);
    for (i = 0; i < 8; i++) {
        IDCT_ROW( (&block[8*i]), (&temp[8*i]) );
    }
}

void ff_bink_idct_add_c(uint8_t *dest, int linesize, DCTELEM *block)
{
    int i, j;

    ff_bink_idct_c(block);
    for (i = 0; i < 8; i++, dest += linesize, block += 8)
        for (j = 0; j < 8; j++)
             dest[j] += block[j];
}

void ff_bink_idct_put_c(uint8_t *dest, int linesize, DCTELEM *block)
{
    int i;
    int temp[64];
    for (i = 0; i < 8; i++)
        bink_idct_col(&temp[i], &block[i]);
    for (i = 0; i < 8; i++) {
        IDCT_ROW( (&dest[i*linesize]), (&temp[8*i]) );
    }
}