/src/ffmpeg/libavcodec/simple_idct_template.c

Source
/*
 * Simple IDCT
 *
 * Copyright (c) 2001 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
 * simpleidct in C.
 */

/* Based upon some commented-out C code from mpeg2dec (idct_mmx.c
 * written by Aaron Holtzman <aholtzma@ess.engr.uvic.ca>). */

#include "bit_depth_template.c"

#undef W1
#undef W2
#undef W3
#undef W4
#undef W5
#undef W6
#undef W7
#undef ROW_SHIFT
#undef COL_SHIFT
#undef DC_SHIFT
#undef MUL
#undef MAC

#if BIT_DEPTH == 8

#define W1  22725  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
#define W2  21407  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
#define W3  19266  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
#define W4  16383  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
#define W5  12873  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
#define W6  8867   //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
#define W7  4520   //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5

#define ROW_SHIFT 11
#define COL_SHIFT 20
#define DC_SHIFT 3

#define MUL(a, b)    MUL16(a, b)
#define MAC(a, b, c) MAC16(a, b, c)

#elif BIT_DEPTH == 10 || BIT_DEPTH == 12

# if BIT_DEPTH == 10
#define W1 22725 // 90901
#define W2 21407 //  85627
#define W3 19265 //  77062
#define W4 16384 //  65535
#define W5 12873 //  51491
#define W6  8867 //  35468
#define W7  4520 //  18081

#   ifdef EXTRA_SHIFT
#define ROW_SHIFT 13
#define COL_SHIFT 18
#define DC_SHIFT  1
#   elif IN_IDCT_DEPTH == 32
#define ROW_SHIFT 13
#define COL_SHIFT 21
#define DC_SHIFT  2
#   else
#define ROW_SHIFT 12
#define COL_SHIFT 19
#define DC_SHIFT  2
#   endif

# else
#define W1 45451
#define W2 42813
#define W3 38531
#define W4 32767
#define W5 25746
#define W6 17734
#define W7 9041

#define ROW_SHIFT 16
#define COL_SHIFT 17
#define DC_SHIFT -1
# endif

#define MUL(a, b)    ((int)((SUINT)(a) * (b)))
#define MAC(a, b, c) ((a) += (SUINT)(b) * (c))

#else

#error "Unsupported bitdepth"

#endif

#ifdef EXTRA_SHIFT
static inline void FUNC(idctRowCondDC_extrashift)(int16_t *row, int extra_shift)
#else
static inline void FUNC6(idctRowCondDC)(idctin *row, int extra_shift)
#endif
{
    SUINT a0, a1, a2, a3, b0, b1, b2, b3;

// TODO: Add DC-only support for int32_t input
#if IN_IDCT_DEPTH == 16
#if HAVE_FAST_64BIT
#define ROW0_MASK (0xffffULL << 48 * HAVE_BIGENDIAN)
    if (((AV_RN64A(row) & ~ROW0_MASK) | AV_RN64A(row+4)) == 0) {
        uint64_t temp;
        if (DC_SHIFT - extra_shift >= 0) {
            temp = (row[0] * (1 << (DC_SHIFT - extra_shift))) & 0xffff;
        } else {
            temp = ((row[0] + (1<<(extra_shift - DC_SHIFT-1))) >> (extra_shift - DC_SHIFT)) & 0xffff;
        }
        temp += temp * (1 << 16);
        temp += temp * ((uint64_t) 1 << 32);
        AV_WN64A(row, temp);
        AV_WN64A(row + 4, temp);
        return;
    }
#else
    if (!(AV_RN32A(row+2) |
          AV_RN32A(row+4) |
          AV_RN32A(row+6) |
          row[1])) {
        uint32_t temp;
        if (DC_SHIFT - extra_shift >= 0) {
            temp = (row[0] * (1 << (DC_SHIFT - extra_shift))) & 0xffff;
        } else {
            temp = ((row[0] + (1<<(extra_shift - DC_SHIFT-1))) >> (extra_shift - DC_SHIFT)) & 0xffff;
        }
        temp += temp * (1 << 16);
        AV_WN32A(row, temp);
        AV_WN32A(row+2, temp);
        AV_WN32A(row+4, temp);
        AV_WN32A(row+6, temp);
        return;
    }
#endif
#endif

    a0 = ((SUINT)W4 * row[0]) + (1 << (ROW_SHIFT + extra_shift - 1));
    a1 = a0;
    a2 = a0;
    a3 = a0;

    a0 += (SUINT)W2 * row[2];
    a1 += (SUINT)W6 * row[2];
    a2 -= (SUINT)W6 * row[2];
    a3 -= (SUINT)W2 * row[2];

    b0 = MUL(W1, row[1]);
    MAC(b0, W3, row[3]);
    b1 = MUL(W3, row[1]);
    MAC(b1, -W7, row[3]);
    b2 = MUL(W5, row[1]);
    MAC(b2, -W1, row[3]);
    b3 = MUL(W7, row[1]);
    MAC(b3, -W5, row[3]);

#if IN_IDCT_DEPTH == 32
    if (AV_RN64A(row + 4) | AV_RN64A(row + 6)) {
#else
    if (AV_RN64A(row + 4)) {
#endif
        a0 += (SUINT)  W4*row[4] + (SUINT)W6*row[6];
        a1 += (SUINT)- W4*row[4] - (SUINT)W2*row[6];
        a2 += (SUINT)- W4*row[4] + (SUINT)W2*row[6];
        a3 += (SUINT)  W4*row[4] - (SUINT)W6*row[6];

        MAC(b0,  W5, row[5]);
        MAC(b0,  W7, row[7]);

        MAC(b1, -W1, row[5]);
        MAC(b1, -W5, row[7]);

        MAC(b2,  W7, row[5]);
        MAC(b2,  W3, row[7]);

        MAC(b3,  W3, row[5]);
        MAC(b3, -W1, row[7]);
    }

    row[0] = (int)(a0 + b0) >> (ROW_SHIFT + extra_shift);
    row[7] = (int)(a0 - b0) >> (ROW_SHIFT + extra_shift);
    row[1] = (int)(a1 + b1) >> (ROW_SHIFT + extra_shift);
    row[6] = (int)(a1 - b1) >> (ROW_SHIFT + extra_shift);
    row[2] = (int)(a2 + b2) >> (ROW_SHIFT + extra_shift);
    row[5] = (int)(a2 - b2) >> (ROW_SHIFT + extra_shift);
    row[3] = (int)(a3 + b3) >> (ROW_SHIFT + extra_shift);
    row[4] = (int)(a3 - b3) >> (ROW_SHIFT + extra_shift);
}

#define IDCT_COLS do {                                  \
        a0 = (SUINT)W4 * (col[8*0] + ((1<<(COL_SHIFT-1))/W4)); \
        a1 = a0;                                        \
        a2 = a0;                                        \
        a3 = a0;                                        \
                                                        \
        a0 += (SUINT) W2*col[8*2];                             \
        a1 += (SUINT) W6*col[8*2];                             \
        a2 += (SUINT)-W6*col[8*2];                             \
        a3 += (SUINT)-W2*col[8*2];                             \
                                                        \
        b0 = MUL(W1, col[8*1]);                         \
        b1 = MUL(W3, col[8*1]);                         \
        b2 = MUL(W5, col[8*1]);                         \
        b3 = MUL(W7, col[8*1]);                         \
                                                        \
        MAC(b0,  W3, col[8*3]);                         \
        MAC(b1, -W7, col[8*3]);                         \
        MAC(b2, -W1, col[8*3]);                         \
        MAC(b3, -W5, col[8*3]);                         \
                                                        \
        if (col[8*4]) {                                 \
            a0 += (SUINT) W4*col[8*4];                         \
            a1 += (SUINT)-W4*col[8*4];                         \
            a2 += (SUINT)-W4*col[8*4];                         \
            a3 += (SUINT) W4*col[8*4];                         \
        }                                               \
                                                        \
        if (col[8*5]) {                                 \
            MAC(b0,  W5, col[8*5]);                     \
            MAC(b1, -W1, col[8*5]);                     \
            MAC(b2,  W7, col[8*5]);                     \
            MAC(b3,  W3, col[8*5]);                     \
        }                                               \
                                                        \
        if (col[8*6]) {                                 \
            a0 += (SUINT) W6*col[8*6];                         \
            a1 += (SUINT)-W2*col[8*6];                         \
            a2 += (SUINT) W2*col[8*6];                         \
            a3 += (SUINT)-W6*col[8*6];                         \
        }                                               \
                                                        \
        if (col[8*7]) {                                 \
            MAC(b0,  W7, col[8*7]);                     \
            MAC(b1, -W5, col[8*7]);                     \
            MAC(b2,  W3, col[8*7]);                     \
            MAC(b3, -W1, col[8*7]);                     \
        }                                               \
    } while (0)

#ifdef EXTRA_SHIFT
static inline void FUNC(idctSparseCol_extrashift)(int16_t *col)
#else
static inline void FUNC6(idctSparseCol)(idctin *col)
#endif
{
    unsigned a0, a1, a2, a3, b0, b1, b2, b3;

    IDCT_COLS;

    col[0 ] = ((int)(a0 + b0) >> COL_SHIFT);
    col[8 ] = ((int)(a1 + b1) >> COL_SHIFT);
    col[16] = ((int)(a2 + b2) >> COL_SHIFT);
    col[24] = ((int)(a3 + b3) >> COL_SHIFT);
    col[32] = ((int)(a3 - b3) >> COL_SHIFT);
    col[40] = ((int)(a2 - b2) >> COL_SHIFT);
    col[48] = ((int)(a1 - b1) >> COL_SHIFT);
    col[56] = ((int)(a0 - b0) >> COL_SHIFT);
}

#ifndef PRORES_ONLY
#ifndef EXTRA_SHIFT
static inline void FUNC6(idctSparseColPut)(pixel *dest, ptrdiff_t line_size,
                                          idctin *col)
{
    SUINT a0, a1, a2, a3, b0, b1, b2, b3;

    IDCT_COLS;

    dest[0] = av_clip_pixel((int)(a0 + b0) >> COL_SHIFT);
    dest += line_size;
    dest[0] = av_clip_pixel((int)(a1 + b1) >> COL_SHIFT);
    dest += line_size;
    dest[0] = av_clip_pixel((int)(a2 + b2) >> COL_SHIFT);
    dest += line_size;
    dest[0] = av_clip_pixel((int)(a3 + b3) >> COL_SHIFT);
    dest += line_size;
    dest[0] = av_clip_pixel((int)(a3 - b3) >> COL_SHIFT);
    dest += line_size;
    dest[0] = av_clip_pixel((int)(a2 - b2) >> COL_SHIFT);
    dest += line_size;
    dest[0] = av_clip_pixel((int)(a1 - b1) >> COL_SHIFT);
    dest += line_size;
    dest[0] = av_clip_pixel((int)(a0 - b0) >> COL_SHIFT);
}

static inline void FUNC6(idctSparseColAdd)(pixel *dest, ptrdiff_t line_size,
                                          idctin *col)
{
    unsigned a0, a1, a2, a3, b0, b1, b2, b3;

    IDCT_COLS;

    dest[0] = av_clip_pixel(dest[0] + ((int)(a0 + b0) >> COL_SHIFT));
    dest += line_size;
    dest[0] = av_clip_pixel(dest[0] + ((int)(a1 + b1) >> COL_SHIFT));
    dest += line_size;
    dest[0] = av_clip_pixel(dest[0] + ((int)(a2 + b2) >> COL_SHIFT));
    dest += line_size;
    dest[0] = av_clip_pixel(dest[0] + ((int)(a3 + b3) >> COL_SHIFT));
    dest += line_size;
    dest[0] = av_clip_pixel(dest[0] + ((int)(a3 - b3) >> COL_SHIFT));
    dest += line_size;
    dest[0] = av_clip_pixel(dest[0] + ((int)(a2 - b2) >> COL_SHIFT));
    dest += line_size;
    dest[0] = av_clip_pixel(dest[0] + ((int)(a1 - b1) >> COL_SHIFT));
    dest += line_size;
    dest[0] = av_clip_pixel(dest[0] + ((int)(a0 - b0) >> COL_SHIFT));
}

void FUNC6(ff_simple_idct_put)(uint8_t *dest_, ptrdiff_t line_size, int16_t *block_)
{
    idctin *block = (idctin *)block_;
    pixel *dest = (pixel *)dest_;
    int i;

    line_size /= sizeof(pixel);

    for (i = 0; i < 8; i++)
        FUNC6(idctRowCondDC)(block + i*8, 0);

    for (i = 0; i < 8; i++)
        FUNC6(idctSparseColPut)(dest + i, line_size, block + i);
}

#if IN_IDCT_DEPTH == 16
void FUNC6(ff_simple_idct_add)(uint8_t *dest_, ptrdiff_t line_size, int16_t *block)
{
    pixel *dest = (pixel *)dest_;
    int i;

    line_size /= sizeof(pixel);

    for (i = 0; i < 8; i++)
        FUNC6(idctRowCondDC)(block + i*8, 0);

    for (i = 0; i < 8; i++)
        FUNC6(idctSparseColAdd)(dest + i, line_size, block + i);
}

void FUNC6(ff_simple_idct)(int16_t *block)
{
    int i;

    for (i = 0; i < 8; i++)
        FUNC6(idctRowCondDC)(block + i*8, 0);

    for (i = 0; i < 8; i++)
        FUNC6(idctSparseCol)(block + i);
}
#endif
#endif
#endif /* PRORES_ONLY */

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Created: 2026-07-25 07:52