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FFmpeg/libavcodec/lossless_videoencdsp.c

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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 "config.h"
#include "libavutil/attributes.h"
#include "lossless_videoencdsp.h"
#include "mathops.h"
// 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
#define pb_7f (~0UL / 255 * 0x7f)
#define pb_80 (~0UL / 255 * 0x80)
static void diff_bytes_c(uint8_t *dst, const uint8_t *src1, const uint8_t *src2, intptr_t w)
{
long i;
#if !HAVE_FAST_UNALIGNED
if (((long)src1 | (long)src2) & (sizeof(long) - 1)) {
for (i = 0; i + 7 < w; i += 8) {
dst[i + 0] = src1[i + 0] - src2[i + 0];
dst[i + 1] = src1[i + 1] - src2[i + 1];
dst[i + 2] = src1[i + 2] - src2[i + 2];
dst[i + 3] = src1[i + 3] - src2[i + 3];
dst[i + 4] = src1[i + 4] - src2[i + 4];
dst[i + 5] = src1[i + 5] - src2[i + 5];
dst[i + 6] = src1[i + 6] - src2[i + 6];
dst[i + 7] = src1[i + 7] - src2[i + 7];
}
} else
#endif
for (i = 0; i <= w - (int) sizeof(long); i += sizeof(long)) {
long a = *(long *) (src1 + i);
long b = *(long *) (src2 + i);
*(long *) (dst + i) = ((a | pb_80) - (b & pb_7f)) ^
((a ^ b ^ pb_80) & pb_80);
}
for (; i < w; i++)
dst[i + 0] = src1[i + 0] - src2[i + 0];
}
static void sub_median_pred_c(uint8_t *dst, const uint8_t *src1,
const uint8_t *src2, intptr_t w,
int *left, int *left_top)
{
int i;
uint8_t l, lt;
l = *left;
lt = *left_top;
for (i = 0; i < w; i++) {
const int pred = mid_pred(l, src1[i], (l + src1[i] - lt) & 0xFF);
lt = src1[i];
l = src2[i];
dst[i] = l - pred;
}
*left = l;
*left_top = lt;
}
av_cold void ff_llvidencdsp_init(LLVidEncDSPContext *c)
{
c->diff_bytes = diff_bytes_c;
c->sub_median_pred = sub_median_pred_c;
if (ARCH_X86)
ff_llvidencdsp_init_x86(c);
}