FFmpeg/libavcodec/jpeg2000dsp.c

/*
 * JPEG 2000 DSP functions
 * Copyright (c) 2007 Kamil Nowosad
 * Copyright (c) 2013 Nicolas Bertrand <nicoinattendu@gmail.com>
 *
 * 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 "config.h"
#include "libavutil/attributes.h"
#include "jpeg2000dsp.h"

/* Inverse ICT parameters in float and integer.
 * int value = (float value) * (1<<16) */
static const float f_ict_params[4] = {
    1.402f,
    0.34413f,
    0.71414f,
    1.772f
};

static const int i_ict_params[4] = {
     91881,
     22553,
     46802,
    116130
};

static void ict_float(void *_src0, void *_src1, void *_src2, int csize)
{
    float *src0 = _src0, *src1 = _src1, *src2 = _src2;
    float i0f, i1f, i2f;
    int i;

    for (i = 0; i < csize; i++) {
        i0f = *src0 + (f_ict_params[0] * *src2);
        i1f = *src0 - (f_ict_params[1] * *src1)
                    - (f_ict_params[2] * *src2);
        i2f = *src0 + (f_ict_params[3] * *src1);
        *src0++ = i0f;
        *src1++ = i1f;
        *src2++ = i2f;
    }
}

static void ict_int(void *_src0, void *_src1, void *_src2, int csize)
{
    int32_t *src0 = _src0, *src1 = _src1, *src2 = _src2;
    int32_t i0, i1, i2;
    int i;

    for (i = 0; i < csize; i++) {
        i0 = *src0 + (((i_ict_params[0] * *src2) + (1 << 15)) >> 16);
        i1 = *src0 - (((i_ict_params[1] * *src1) + (1 << 15)) >> 16)
                   - (((i_ict_params[2] * *src2) + (1 << 15)) >> 16);
        i2 = *src0 + (((i_ict_params[3] * *src1) + (1 << 15)) >> 16);
        *src0++ = i0;
        *src1++ = i1;
        *src2++ = i2;
    }
}

static void rct_int(void *_src0, void *_src1, void *_src2, int csize)
{
    int32_t *src0 = _src0, *src1 = _src1, *src2 = _src2;
    int32_t i0, i1, i2;
    int i;

    for (i = 0; i < csize; i++) {
        i1 = *src0 - (*src2 + *src1 >> 2);
        i0 = i1 + *src2;
        i2 = i1 + *src1;
        *src0++ = i0;
        *src1++ = i1;
        *src2++ = i2;
    }
}

av_cold void ff_jpeg2000dsp_init(Jpeg2000DSPContext *c)
{
    c->mct_decode[FF_DWT97]     = ict_float;
    c->mct_decode[FF_DWT53]     = rct_int;
    c->mct_decode[FF_DWT97_INT] = ict_int;
}