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/*
* 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 <stdint.h>
#include "libavutil/attributes.h"
#include "libavutil/common.h"
#include "config.h"
#include "h263dsp.h"
const uint8_t ff_h263_loop_filter_strength[32] = {
0, 1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 7,
7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 12
};
static void h263_h_loop_filter_c(uint8_t *src, int stride, int qscale)
{
int y;
const int strength = ff_h263_loop_filter_strength[qscale];
for (y = 0; y < 8; y++) {
int d1, d2, ad1;
int p0 = src[y * stride - 2];
int p1 = src[y * stride - 1];
int p2 = src[y * stride + 0];
int p3 = src[y * stride + 1];
int d = (p0 - p3 + 4 * (p2 - p1)) / 8;
if (d < -2 * strength)
d1 = 0;
else if (d < -strength)
d1 = -2 * strength - d;
else if (d < strength)
d1 = d;
else if (d < 2 * strength)
d1 = 2 * strength - d;
else
d1 = 0;
p1 += d1;
p2 -= d1;
if (p1 & 256)
p1 = ~(p1 >> 31);
if (p2 & 256)
p2 = ~(p2 >> 31);
src[y * stride - 1] = p1;
src[y * stride + 0] = p2;
ad1 = FFABS(d1) >> 1;
d2 = av_clip((p0 - p3) / 4, -ad1, ad1);
src[y * stride - 2] = p0 - d2;
src[y * stride + 1] = p3 + d2;
}
}
static void h263_v_loop_filter_c(uint8_t *src, int stride, int qscale)
{
int x;
const int strength = ff_h263_loop_filter_strength[qscale];
for (x = 0; x < 8; x++) {
int d1, d2, ad1;
int p0 = src[x - 2 * stride];
int p1 = src[x - 1 * stride];
int p2 = src[x + 0 * stride];
int p3 = src[x + 1 * stride];
int d = (p0 - p3 + 4 * (p2 - p1)) / 8;
if (d < -2 * strength)
d1 = 0;
else if (d < -strength)
d1 = -2 * strength - d;
else if (d < strength)
d1 = d;
else if (d < 2 * strength)
d1 = 2 * strength - d;
else
d1 = 0;
p1 += d1;
p2 -= d1;
if (p1 & 256)
p1 = ~(p1 >> 31);
if (p2 & 256)
p2 = ~(p2 >> 31);
src[x - 1 * stride] = p1;
src[x + 0 * stride] = p2;
ad1 = FFABS(d1) >> 1;
d2 = av_clip((p0 - p3) / 4, -ad1, ad1);
src[x - 2 * stride] = p0 - d2;
src[x + stride] = p3 + d2;
}
}
av_cold void ff_h263dsp_init(H263DSPContext *ctx)
{
ctx->h263_h_loop_filter = h263_h_loop_filter_c;
ctx->h263_v_loop_filter = h263_v_loop_filter_c;
if (ARCH_X86)
ff_h263dsp_init_x86(ctx);
}
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