FFmpeg/libavcodec/snow_dwt.c

/*
 * Copyright (C) 2004-2010 Michael Niedermayer <michaelni@gmx.at>
 * Copyright (C) 2008 David Conrad
 *
 * 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 "libavutil/avassert.h"
#include "libavutil/common.h"
#include "dsputil.h"
#include "snow_dwt.h"

int ff_slice_buffer_init(slice_buffer *buf, int line_count,
                         int max_allocated_lines, int line_width,
                         IDWTELEM *base_buffer)
{
    int i;

    buf->base_buffer = base_buffer;
    buf->line_count  = line_count;
    buf->line_width  = line_width;
    buf->data_count  = max_allocated_lines;
    buf->line        = av_mallocz(sizeof(IDWTELEM *) * line_count);
    if (!buf->line)
        return AVERROR(ENOMEM);
    buf->data_stack  = av_malloc(sizeof(IDWTELEM *) * max_allocated_lines);
    if (!buf->data_stack) {
        av_freep(&buf->line);
        return AVERROR(ENOMEM);
    }

    for (i = 0; i < max_allocated_lines; i++) {
        buf->data_stack[i] = av_malloc(sizeof(IDWTELEM) * line_width);
        if (!buf->data_stack[i]) {
            for (i--; i >=0; i--)
                av_freep(&buf->data_stack[i]);
            av_freep(&buf->data_stack);
            av_freep(&buf->line);
            return AVERROR(ENOMEM);
        }
    }

    buf->data_stack_top = max_allocated_lines - 1;
    return 0;
}

IDWTELEM *ff_slice_buffer_load_line(slice_buffer *buf, int line)
{
    IDWTELEM *buffer;

    av_assert0(buf->data_stack_top >= 0);
//  av_assert1(!buf->line[line]);
    if (buf->line[line])
        return buf->line[line];

    buffer = buf->data_stack[buf->data_stack_top];
    buf->data_stack_top--;
    buf->line[line] = buffer;

    return buffer;
}

void ff_slice_buffer_release(slice_buffer *buf, int line)
{
    IDWTELEM *buffer;

    av_assert1(line >= 0 && line < buf->line_count);
    av_assert1(buf->line[line]);

    buffer = buf->line[line];
    buf->data_stack_top++;
    buf->data_stack[buf->data_stack_top] = buffer;
    buf->line[line]                      = NULL;
}

void ff_slice_buffer_flush(slice_buffer *buf)
{
    int i;
    for (i = 0; i < buf->line_count; i++)
        if (buf->line[i])
            ff_slice_buffer_release(buf, i);
}

void ff_slice_buffer_destroy(slice_buffer *buf)
{
    int i;
    ff_slice_buffer_flush(buf);

    for (i = buf->data_count - 1; i >= 0; i--)
        av_freep(&buf->data_stack[i]);
    av_freep(&buf->data_stack);
    av_freep(&buf->line);
}

static inline int mirror(int v, int m)
{
    while ((unsigned)v > (unsigned)m) {
        v = -v;
        if (v < 0)
            v += 2 * m;
    }
    return v;
}

static av_always_inline void lift(DWTELEM *dst, DWTELEM *src, DWTELEM *ref,
                                  int dst_step, int src_step, int ref_step,
                                  int width, int mul, int add, int shift,
                                  int highpass, int inverse)
{
    const int mirror_left  = !highpass;
    const int mirror_right = (width & 1) ^ highpass;
    const int w            = (width >> 1) - 1 + (highpass & width);
    int i;

#define LIFT(src, ref, inv) ((src) + ((inv) ? -(ref) : +(ref)))
    if (mirror_left) {
        dst[0] = LIFT(src[0], ((mul * 2 * ref[0] + add) >> shift), inverse);
        dst   += dst_step;
        src   += src_step;
    }

    for (i = 0; i < w; i++)
        dst[i * dst_step] = LIFT(src[i * src_step],
                                 ((mul * (ref[i * ref_step] +
                                          ref[(i + 1) * ref_step]) +
                                   add) >> shift),
                                 inverse);

    if (mirror_right)
        dst[w * dst_step] = LIFT(src[w * src_step],
                                 ((mul * 2 * ref[w * ref_step] + add) >> shift),
                                 inverse);
}

static av_always_inline void liftS(DWTELEM *dst, DWTELEM *src, DWTELEM *ref,
                                   int dst_step, int src_step, int ref_step,
                                   int width, int mul, int add, int shift,
                                   int highpass, int inverse)
{
    const int mirror_left  = !highpass;
    const int mirror_right = (width & 1) ^ highpass;
    const int w            = (width >> 1) - 1 + (highpass & width);
    int i;

    av_assert1(shift == 4);
#define LIFTS(src, ref, inv)                                            \
    ((inv) ? (src) + (((ref) + 4 * (src)) >> shift)                     \
           : -((-16 * (src) + (ref) + add /                             \
                4 + 1 + (5 << 25)) / (5 * 4) - (1 << 23)))
    if (mirror_left) {
        dst[0] = LIFTS(src[0], mul * 2 * ref[0] + add, inverse);
        dst   += dst_step;
        src   += src_step;
    }

    for (i = 0; i < w; i++)
        dst[i * dst_step] = LIFTS(src[i * src_step],
                                  mul * (ref[i * ref_step] +
                                         ref[(i + 1) * ref_step]) + add,
                                  inverse);

    if (mirror_right)
        dst[w * dst_step] = LIFTS(src[w * src_step],
                                  mul * 2 * ref[w * ref_step] + add,
                                  inverse);
}

static void horizontal_decompose53i(DWTELEM *b, DWTELEM *temp, int width)
{
    const int width2 = width >> 1;
    int x;
    const int w2 = (width + 1) >> 1;

    for (x = 0; x < width2; x++) {
        temp[x]      = b[2 * x];
        temp[x + w2] = b[2 * x + 1];
    }
    if (width & 1)
        temp[x] = b[2 * x];
    lift(b + w2, temp + w2, temp,   1, 1, 1, width, -1, 0, 1, 1, 0);
    lift(b,      temp,      b + w2, 1, 1, 1, width,  1, 2, 2, 0, 0);
}

static void vertical_decompose53iH0(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2,
                                    int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] -= (b0[i] + b2[i]) >> 1;
}

static void vertical_decompose53iL0(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2,
                                    int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] += (b0[i] + b2[i] + 2) >> 2;
}

static void spatial_decompose53i(DWTELEM *buffer, DWTELEM *temp,
                                 int width, int height, int stride)
{
    int y;
    DWTELEM *b0 = buffer + mirror(-2 - 1, height - 1) * stride;
    DWTELEM *b1 = buffer + mirror(-2,     height - 1) * stride;

    for (y = -2; y < height; y += 2) {
        DWTELEM *b2 = buffer + mirror(y + 1, height - 1) * stride;
        DWTELEM *b3 = buffer + mirror(y + 2, height - 1) * stride;

        if (y + 1 < (unsigned)height)
            horizontal_decompose53i(b2, temp, width);
        if (y + 2 < (unsigned)height)
            horizontal_decompose53i(b3, temp, width);

        if (y + 1 < (unsigned)height)
            vertical_decompose53iH0(b1, b2, b3, width);
        if (y + 0 < (unsigned)height)
            vertical_decompose53iL0(b0, b1, b2, width);

        b0 = b2;
        b1 = b3;
    }
}

static void horizontal_decompose97i(DWTELEM *b, DWTELEM *temp, int width)
{
    const int w2 = (width + 1) >> 1;

    lift(temp + w2, b + 1, b,         1, 2, 2, width, W_AM, W_AO, W_AS, 1, 1);
    liftS(temp,     b,     temp + w2, 1, 2, 1, width, W_BM, W_BO, W_BS, 0, 0);
    lift(b + w2, temp + w2, temp,     1, 1, 1, width, W_CM, W_CO, W_CS, 1, 0);
    lift(b,      temp,      b + w2,   1, 1, 1, width, W_DM, W_DO, W_DS, 0, 0);
}

static void vertical_decompose97iH0(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2,
                                    int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] -= (W_AM * (b0[i] + b2[i]) + W_AO) >> W_AS;
}

static void vertical_decompose97iH1(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2,
                                    int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] += (W_CM * (b0[i] + b2[i]) + W_CO) >> W_CS;
}

static void vertical_decompose97iL0(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2,
                                    int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] = (16 * 4 * b1[i] - 4 * (b0[i] + b2[i]) + W_BO * 5 + (5 << 27)) /
                (5 * 16) - (1 << 23);
}

static void vertical_decompose97iL1(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2,
                                    int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] += (W_DM * (b0[i] + b2[i]) + W_DO) >> W_DS;
}

static void spatial_decompose97i(DWTELEM *buffer, DWTELEM *temp,
                                 int width, int height, int stride)
{
    int y;
    DWTELEM *b0 = buffer + mirror(-4 - 1, height - 1) * stride;
    DWTELEM *b1 = buffer + mirror(-4,     height - 1) * stride;
    DWTELEM *b2 = buffer + mirror(-4 + 1, height - 1) * stride;
    DWTELEM *b3 = buffer + mirror(-4 + 2, height - 1) * stride;

    for (y = -4; y < height; y += 2) {
        DWTELEM *b4 = buffer + mirror(y + 3, height - 1) * stride;
        DWTELEM *b5 = buffer + mirror(y + 4, height - 1) * stride;

        if (y + 3 < (unsigned)height)
            horizontal_decompose97i(b4, temp, width);
        if (y + 4 < (unsigned)height)
            horizontal_decompose97i(b5, temp, width);

        if (y + 3 < (unsigned)height)
            vertical_decompose97iH0(b3, b4, b5, width);
        if (y + 2 < (unsigned)height)
            vertical_decompose97iL0(b2, b3, b4, width);
        if (y + 1 < (unsigned)height)
            vertical_decompose97iH1(b1, b2, b3, width);
        if (y + 0 < (unsigned)height)
            vertical_decompose97iL1(b0, b1, b2, width);

        b0 = b2;
        b1 = b3;
        b2 = b4;
        b3 = b5;
    }
}

void ff_spatial_dwt(DWTELEM *buffer, DWTELEM *temp, int width, int height,
                    int stride, int type, int decomposition_count)
{
    int level;

    for (level = 0; level < decomposition_count; level++) {
        switch (type) {
        case DWT_97:
            spatial_decompose97i(buffer, temp,
                                 width >> level, height >> level,
                                 stride << level);
            break;
        case DWT_53:
            spatial_decompose53i(buffer, temp,
                                 width >> level, height >> level,
                                 stride << level);
            break;
        }
    }
}

static void horizontal_compose53i(IDWTELEM *b, IDWTELEM *temp, int width)
{
    const int width2 = width >> 1;
    const int w2     = (width + 1) >> 1;
    int x;

    for (x = 0; x < width2; x++) {
        temp[2 * x]     = b[x];
        temp[2 * x + 1] = b[x + w2];
    }
    if (width & 1)
        temp[2 * x] = b[x];

    b[0] = temp[0] - ((temp[1] + 1) >> 1);
    for (x = 2; x < width - 1; x += 2) {
        b[x]     = temp[x]     - ((temp[x - 1] + temp[x + 1] + 2) >> 2);
        b[x - 1] = temp[x - 1] + ((b[x - 2]    + b[x]        + 1) >> 1);
    }
    if (width & 1) {
        b[x]     = temp[x]     - ((temp[x - 1]     + 1) >> 1);
        b[x - 1] = temp[x - 1] + ((b[x - 2] + b[x] + 1) >> 1);
    } else
        b[x - 1] = temp[x - 1] + b[x - 2];
}

static void vertical_compose53iH0(IDWTELEM *b0, IDWTELEM *b1, IDWTELEM *b2,
                                  int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] += (b0[i] + b2[i]) >> 1;
}

static void vertical_compose53iL0(IDWTELEM *b0, IDWTELEM *b1, IDWTELEM *b2,
                                  int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] -= (b0[i] + b2[i] + 2) >> 2;
}

static void spatial_compose53i_buffered_init(DWTCompose *cs, slice_buffer *sb,
                                             int height, int stride_line)
{
    cs->b0 = slice_buffer_get_line(sb,
                                   mirror(-1 - 1, height - 1) * stride_line);
    cs->b1 = slice_buffer_get_line(sb, mirror(-1, height - 1) * stride_line);
    cs->y  = -1;
}

static void spatial_compose53i_init(DWTCompose *cs, IDWTELEM *buffer,
                                    int height, int stride)
{
    cs->b0 = buffer + mirror(-1 - 1, height - 1) * stride;
    cs->b1 = buffer + mirror(-1,     height - 1) * stride;
    cs->y  = -1;
}

static void spatial_compose53i_dy_buffered(DWTCompose *cs, slice_buffer *sb,
                                           IDWTELEM *temp,
                                           int width, int height,
                                           int stride_line)
{
    int y = cs->y;

    IDWTELEM *b0 = cs->b0;
    IDWTELEM *b1 = cs->b1;
    IDWTELEM *b2 = slice_buffer_get_line(sb,
                                         mirror(y + 1, height - 1) *
                                         stride_line);
    IDWTELEM *b3 = slice_buffer_get_line(sb,
                                         mirror(y + 2, height - 1) *
                                         stride_line);

    if (y + 1 < (unsigned)height && y < (unsigned)height) {
        int x;

        for (x = 0; x < width; x++) {
            b2[x] -= (b1[x] + b3[x] + 2) >> 2;
            b1[x] += (b0[x] + b2[x])     >> 1;
        }
    } else {
        if (y + 1 < (unsigned)height)
            vertical_compose53iL0(b1, b2, b3, width);
        if (y + 0 < (unsigned)height)
            vertical_compose53iH0(b0, b1, b2, width);
    }

    if (y - 1 < (unsigned)height)
        horizontal_compose53i(b0, temp, width);
    if (y + 0 < (unsigned)height)
        horizontal_compose53i(b1, temp, width);

    cs->b0  = b2;
    cs->b1  = b3;
    cs->y  += 2;
}

static void spatial_compose53i_dy(DWTCompose *cs, IDWTELEM *buffer,
                                  IDWTELEM *temp, int width, int height,
                                  int stride)
{
    int y        = cs->y;
    IDWTELEM *b0 = cs->b0;
    IDWTELEM *b1 = cs->b1;
    IDWTELEM *b2 = buffer + mirror(y + 1, height - 1) * stride;
    IDWTELEM *b3 = buffer + mirror(y + 2, height - 1) * stride;

    if (y + 1 < (unsigned)height)
        vertical_compose53iL0(b1, b2, b3, width);
    if (y + 0 < (unsigned)height)
        vertical_compose53iH0(b0, b1, b2, width);

    if (y - 1 < (unsigned)height)
        horizontal_compose53i(b0, temp, width);
    if (y + 0 < (unsigned)height)
        horizontal_compose53i(b1, temp, width);

    cs->b0  = b2;
    cs->b1  = b3;
    cs->y  += 2;
}

void ff_snow_horizontal_compose97i(IDWTELEM *b, IDWTELEM *temp, int width)
{
    const int w2 = (width + 1) >> 1;
    int x;

    temp[0] = b[0] - ((3 * b[w2] + 2) >> 2);
    for (x = 1; x < (width >> 1); x++) {
        temp[2 * x]     = b[x] - ((3 * (b[x + w2 - 1] + b[x + w2]) + 4) >> 3);
        temp[2 * x - 1] = b[x + w2 - 1] - temp[2 * x - 2] - temp[2 * x];
    }
    if (width & 1) {
        temp[2 * x]     = b[x] - ((3 * b[x + w2 - 1] + 2) >> 2);
        temp[2 * x - 1] = b[x + w2 - 1] - temp[2 * x - 2] - temp[2 * x];
    } else
        temp[2 * x - 1] = b[x + w2 - 1] - 2 * temp[2 * x - 2];

    b[0] = temp[0] + ((2 * temp[0] + temp[1] + 4) >> 3);
    for (x = 2; x < width - 1; x += 2) {
        b[x]     = temp[x] + ((4 * temp[x] + temp[x - 1] + temp[x + 1] + 8) >> 4);
        b[x - 1] = temp[x - 1] + ((3 * (b[x - 2] + b[x])) >> 1);
    }
    if (width & 1) {
        b[x]     = temp[x] + ((2 * temp[x] + temp[x - 1] + 4) >> 3);
        b[x - 1] = temp[x - 1] + ((3 * (b[x - 2] + b[x])) >> 1);
    } else
        b[x - 1] = temp[x - 1] + 3 * b[x - 2];
}

static void vertical_compose97iH0(IDWTELEM *b0, IDWTELEM *b1, IDWTELEM *b2,
                                  int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] += (W_AM * (b0[i] + b2[i]) + W_AO) >> W_AS;
}

static void vertical_compose97iH1(IDWTELEM *b0, IDWTELEM *b1, IDWTELEM *b2,
                                  int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] -= (W_CM * (b0[i] + b2[i]) + W_CO) >> W_CS;
}

static void vertical_compose97iL0(IDWTELEM *b0, IDWTELEM *b1, IDWTELEM *b2,
                                  int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] += (W_BM * (b0[i] + b2[i]) + 4 * b1[i] + W_BO) >> W_BS;
}

static void vertical_compose97iL1(IDWTELEM *b0, IDWTELEM *b1, IDWTELEM *b2,
                                  int width)
{
    int i;

    for (i = 0; i < width; i++)
        b1[i] -= (W_DM * (b0[i] + b2[i]) + W_DO) >> W_DS;
}

void ff_snow_vertical_compose97i(IDWTELEM *b0, IDWTELEM *b1, IDWTELEM *b2,
                                 IDWTELEM *b3, IDWTELEM *b4, IDWTELEM *b5,
                                 int width)
{
    int i;

    for (i = 0; i < width; i++) {
        b4[i] -= (W_DM * (b3[i] + b5[i]) + W_DO) >> W_DS;
        b3[i] -= (W_CM * (b2[i] + b4[i]) + W_CO) >> W_CS;
        b2[i] += (W_BM * (b1[i] + b3[i]) + 4 * b2[i] + W_BO) >> W_BS;
        b1[i] += (W_AM * (b0[i] + b2[i]) + W_AO) >> W_AS;
    }
}

static void spatial_compose97i_buffered_init(DWTCompose *cs, slice_buffer *sb,
                                             int height, int stride_line)
{
    cs->b0 = slice_buffer_get_line(sb, mirror(-3 - 1, height - 1) * stride_line);
    cs->b1 = slice_buffer_get_line(sb, mirror(-3,     height - 1) * stride_line);
    cs->b2 = slice_buffer_get_line(sb, mirror(-3 + 1, height - 1) * stride_line);
    cs->b3 = slice_buffer_get_line(sb, mirror(-3 + 2, height - 1) * stride_line);
    cs->y  = -3;
}

static void spatial_compose97i_init(DWTCompose *cs, IDWTELEM *buffer, int height,
                                    int stride)
{
    cs->b0 = buffer + mirror(-3 - 1, height - 1) * stride;
    cs->b1 = buffer + mirror(-3,     height - 1) * stride;
    cs->b2 = buffer + mirror(-3 + 1, height - 1) * stride;
    cs->b3 = buffer + mirror(-3 + 2, height - 1) * stride;
    cs->y  = -3;
}

static void spatial_compose97i_dy_buffered(SnowDWTContext *dsp, DWTCompose *cs,
                                           slice_buffer * sb, IDWTELEM *temp,
                                           int width, int height,
                                           int stride_line)
{
    int y = cs->y;

    IDWTELEM *b0 = cs->b0;
    IDWTELEM *b1 = cs->b1;
    IDWTELEM *b2 = cs->b2;
    IDWTELEM *b3 = cs->b3;
    IDWTELEM *b4 = slice_buffer_get_line(sb,
                                         mirror(y + 3, height - 1) *
                                         stride_line);
    IDWTELEM *b5 = slice_buffer_get_line(sb,
                                         mirror(y + 4, height - 1) *
                                         stride_line);

    if (y > 0 && y + 4 < height) {
        dsp->vertical_compose97i(b0, b1, b2, b3, b4, b5, width);
    } else {
        if (y + 3 < (unsigned)height)
            vertical_compose97iL1(b3, b4, b5, width);
        if (y + 2 < (unsigned)height)
            vertical_compose97iH1(b2, b3, b4, width);
        if (y + 1 < (unsigned)height)
            vertical_compose97iL0(b1, b2, b3, width);
        if (y + 0 < (unsigned)height)
            vertical_compose97iH0(b0, b1, b2, width);
    }

    if (y - 1 < (unsigned)height)
        dsp->horizontal_compose97i(b0, temp, width);
    if (y + 0 < (unsigned)height)
        dsp->horizontal_compose97i(b1, temp, width);

    cs->b0  = b2;
    cs->b1  = b3;
    cs->b2  = b4;
    cs->b3  = b5;
    cs->y  += 2;
}

static void spatial_compose97i_dy(DWTCompose *cs, IDWTELEM *buffer,
                                  IDWTELEM *temp, int width, int height,
                                  int stride)
{
    int y        = cs->y;
    IDWTELEM *b0 = cs->b0;
    IDWTELEM *b1 = cs->b1;
    IDWTELEM *b2 = cs->b2;
    IDWTELEM *b3 = cs->b3;
    IDWTELEM *b4 = buffer + mirror(y + 3, height - 1) * stride;
    IDWTELEM *b5 = buffer + mirror(y + 4, height - 1) * stride;

    if (y + 3 < (unsigned)height)
        vertical_compose97iL1(b3, b4, b5, width);
    if (y + 2 < (unsigned)height)
        vertical_compose97iH1(b2, b3, b4, width);
    if (y + 1 < (unsigned)height)
        vertical_compose97iL0(b1, b2, b3, width);
    if (y + 0 < (unsigned)height)
        vertical_compose97iH0(b0, b1, b2, width);

    if (y - 1 < (unsigned)height)
        ff_snow_horizontal_compose97i(b0, temp, width);
    if (y + 0 < (unsigned)height)
        ff_snow_horizontal_compose97i(b1, temp, width);

    cs->b0  = b2;
    cs->b1  = b3;
    cs->b2  = b4;
    cs->b3  = b5;
    cs->y  += 2;
}

void ff_spatial_idwt_buffered_init(DWTCompose *cs, slice_buffer *sb, int width,
                                   int height, int stride_line, int type,
                                   int decomposition_count)
{
    int level;
    for (level = decomposition_count - 1; level >= 0; level--) {
        switch (type) {
        case DWT_97:
            spatial_compose97i_buffered_init(cs + level, sb, height >> level,
                                             stride_line << level);
            break;
        case DWT_53:
            spatial_compose53i_buffered_init(cs + level, sb, height >> level,
                                             stride_line << level);
            break;
        }
    }
}

void ff_spatial_idwt_buffered_slice(SnowDWTContext *dsp, DWTCompose *cs,
                                    slice_buffer *slice_buf, IDWTELEM *temp,
                                    int width, int height, int stride_line,
                                    int type, int decomposition_count, int y)
{
    const int support = type == 1 ? 3 : 5;
    int level;
    if (type == 2)
        return;

    for (level = decomposition_count - 1; level >= 0; level--)
        while (cs[level].y <= FFMIN((y >> level) + support, height >> level)) {
            switch (type) {
            case DWT_97:
                spatial_compose97i_dy_buffered(dsp, cs + level, slice_buf, temp,
                                               width >> level,
                                               height >> level,
                                               stride_line << level);
                break;
            case DWT_53:
                spatial_compose53i_dy_buffered(cs + level, slice_buf, temp,
                                               width >> level,
                                               height >> level,
                                               stride_line << level);
                break;
            }
        }
}

static void ff_spatial_idwt_init(DWTCompose *cs, IDWTELEM *buffer, int width,
                                 int height, int stride, int type,
                                 int decomposition_count)
{
    int level;
    for (level = decomposition_count - 1; level >= 0; level--) {
        switch (type) {
        case DWT_97:
            spatial_compose97i_init(cs + level, buffer, height >> level,
                                    stride << level);
            break;
        case DWT_53:
            spatial_compose53i_init(cs + level, buffer, height >> level,
                                    stride << level);
            break;
        }
    }
}

static void ff_spatial_idwt_slice(DWTCompose *cs, IDWTELEM *buffer,
                                  IDWTELEM *temp, int width, int height,
                                  int stride, int type,
                                  int decomposition_count, int y)
{
    const int support = type == 1 ? 3 : 5;
    int level;
    if (type == 2)
        return;

    for (level = decomposition_count - 1; level >= 0; level--)
        while (cs[level].y <= FFMIN((y >> level) + support, height >> level)) {
            switch (type) {
            case DWT_97:
                spatial_compose97i_dy(cs + level, buffer, temp, width >> level,
                                      height >> level, stride << level);
                break;
            case DWT_53:
                spatial_compose53i_dy(cs + level, buffer, temp, width >> level,
                                      height >> level, stride << level);
                break;
            }
        }
}

void ff_spatial_idwt(IDWTELEM *buffer, IDWTELEM *temp, int width, int height,
                     int stride, int type, int decomposition_count)
{
    DWTCompose cs[MAX_DECOMPOSITIONS];
    int y;
    ff_spatial_idwt_init(cs, buffer, width, height, stride, type,
                         decomposition_count);
    for (y = 0; y < height; y += 4)
        ff_spatial_idwt_slice(cs, buffer, temp, width, height, stride, type,
                              decomposition_count, y);
}

static inline int w_c(void *v, uint8_t *pix1, uint8_t *pix2, int line_size,
                      int w, int h, int type)
{
    int s, i, j;
    const int dec_count = w == 8 ? 3 : 4;
    int tmp[32 * 32], tmp2[32];
    int level, ori;
    static const int scale[2][2][4][4] = {
        {
            { // 9/7 8x8 dec=3
                { 268, 239, 239, 213 },
                { 0,   224, 224, 152 },
                { 0,   135, 135, 110 },
            },
            { // 9/7 16x16 or 32x32 dec=4
                { 344, 310, 310, 280 },
                { 0,   320, 320, 228 },
                { 0,   175, 175, 136 },
                { 0,   129, 129, 102 },
            }
        },
        {
            { // 5/3 8x8 dec=3
                { 275, 245, 245, 218 },
                { 0,   230, 230, 156 },
                { 0,   138, 138, 113 },
            },
            { // 5/3 16x16 or 32x32 dec=4
                { 352, 317, 317, 286 },
                { 0,   328, 328, 233 },
                { 0,   180, 180, 140 },
                { 0,   132, 132, 105 },
            }
        }
    };

    for (i = 0; i < h; i++) {
        for (j = 0; j < w; j += 4) {
            tmp[32 * i + j + 0] = (pix1[j + 0] - pix2[j + 0]) << 4;
            tmp[32 * i + j + 1] = (pix1[j + 1] - pix2[j + 1]) << 4;
            tmp[32 * i + j + 2] = (pix1[j + 2] - pix2[j + 2]) << 4;
            tmp[32 * i + j + 3] = (pix1[j + 3] - pix2[j + 3]) << 4;
        }
        pix1 += line_size;
        pix2 += line_size;
    }

    ff_spatial_dwt(tmp, tmp2, w, h, 32, type, dec_count);

    s = 0;
    av_assert1(w == h);
    for (level = 0; level < dec_count; level++)
        for (ori = level ? 1 : 0; ori < 4; ori++) {
            int size   = w >> (dec_count - level);
            int sx     = (ori & 1) ? size : 0;
            int stride = 32 << (dec_count - level);
            int sy     = (ori & 2) ? stride >> 1 : 0;

            for (i = 0; i < size; i++)
                for (j = 0; j < size; j++) {
                    int v = tmp[sx + sy + i * stride + j] *
                            scale[type][dec_count - 3][level][ori];
                    s += FFABS(v);
                }
        }
    av_assert1(s >= 0);
    return s >> 9;
}

static int w53_8_c(void *v, uint8_t *pix1, uint8_t *pix2, int line_size, int h)
{
    return w_c(v, pix1, pix2, line_size, 8, h, 1);
}

static int w97_8_c(void *v, uint8_t *pix1, uint8_t *pix2, int line_size, int h)
{
    return w_c(v, pix1, pix2, line_size, 8, h, 0);
}

static int w53_16_c(void *v, uint8_t *pix1, uint8_t *pix2, int line_size, int h)
{
    return w_c(v, pix1, pix2, line_size, 16, h, 1);
}

static int w97_16_c(void *v, uint8_t *pix1, uint8_t *pix2, int line_size, int h)
{
    return w_c(v, pix1, pix2, line_size, 16, h, 0);
}

int ff_w53_32_c(void *v, uint8_t *pix1, uint8_t *pix2, int line_size, int h)
{
    return w_c(v, pix1, pix2, line_size, 32, h, 1);
}

int ff_w97_32_c(void *v, uint8_t *pix1, uint8_t *pix2, int line_size, int h)
{
    return w_c(v, pix1, pix2, line_size, 32, h, 0);
}

void ff_dsputil_init_dwt(DSPContext *c)
{
    c->w53[0] = w53_16_c;
    c->w53[1] = w53_8_c;
    c->w97[0] = w97_16_c;
    c->w97[1] = w97_8_c;
}

void ff_dwt_init(SnowDWTContext *c)
{
    c->vertical_compose97i   = ff_snow_vertical_compose97i;
    c->horizontal_compose97i = ff_snow_horizontal_compose97i;
    c->inner_add_yblock      = ff_snow_inner_add_yblock;

    if (HAVE_MMX)
        ff_dwt_init_x86(c);
}