FFmpeg/libavcodec/takdsp.c

/*
 * TAK decoder
 * Copyright (c) 2015 Paul B Mahol
 *
 * 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
 */

#include "libavutil/attributes.h"
#include "takdsp.h"
#include "config.h"

static void decorrelate_ls(int32_t *p1, int32_t *p2, int length)
{
    int i;

    for (i = 0; i < length; i++) {
        int32_t a = p1[i];
        int32_t b = p2[i];
        p2[i]     = a + b;
    }
}

static void decorrelate_sr(int32_t *p1, int32_t *p2, int length)
{
    int i;

    for (i = 0; i < length; i++) {
        int32_t a = p1[i];
        int32_t b = p2[i];
        p1[i]     = b - a;
    }
}

static void decorrelate_sm(int32_t *p1, int32_t *p2, int length)
{
    int i;

    for (i = 0; i < length; i++) {
        int32_t a = p1[i];
        int32_t b = p2[i];
        a        -= b >> 1;
        p1[i]     = a;
        p2[i]     = a + b;
    }
}

static void decorrelate_sf(int32_t *p1, int32_t *p2, int length, int dshift, int dfactor)
{
    int i;

    for (i = 0; i < length; i++) {
        int32_t a = p1[i];
        int32_t b = p2[i];
        b         = (unsigned)(dfactor * (b >> dshift) + 128 >> 8) << dshift;
        p1[i]     = b - a;
    }
}

av_cold void ff_takdsp_init(TAKDSPContext *c)
{
    c->decorrelate_ls = decorrelate_ls;
    c->decorrelate_sr = decorrelate_sr;
    c->decorrelate_sm = decorrelate_sm;
    c->decorrelate_sf = decorrelate_sf;

    if (ARCH_X86)
        ff_takdsp_init_x86(c);
}