FFmpeg/libavcodec/lossless_videoencdsp.c
Andreas Rheinhardt a4800643bb avcodec/lossless_videoencdsp: Don't presume alignment in diff_bytes
The alignment of all the parameters in diff_bytes can be
anything the despite the documentation claiming otherwise.
8ecd383122 was based around
said documentation and is therefore insufficient to fix
e.g. the misaligned loads that happen in the huffyuvbgra
and huffyuvbgr24 vsynth FATE-tests.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2024-04-04 23:57:19 +02:00

112 lines
3.4 KiB
C

/*
* 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 "libavutil/intreadwrite.h"
#include "lossless_videoencdsp.h"
#include "mathops.h"
#if HAVE_FAST_64BIT
typedef uint64_t uint_native;
#define READ AV_RN64
#define WRITE AV_WN64
#else
typedef uint32_t uint_native;
#define READ AV_RN32
#define WRITE AV_WN32
#endif
// 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
#define pb_7f (~(uint_native)0 / 255 * 0x7f)
#define pb_80 (~(uint_native)0 / 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 (((uintptr_t)src1 | (uintptr_t)src2) & (sizeof(uint_native) - 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(uint_native); i += sizeof(uint_native)) {
uint_native a = READ(src1 + i);
uint_native b = READ(src2 + i);
WRITE(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;
}
static void sub_left_predict_c(uint8_t *dst, const uint8_t *src,
ptrdiff_t stride, ptrdiff_t width, int height)
{
int i, j;
uint8_t prev = 0x80; /* Set the initial value */
for (j = 0; j < height; j++) {
for (i = 0; i < width; i++) {
*dst++ = src[i] - prev;
prev = src[i];
}
src += stride;
}
}
av_cold void ff_llvidencdsp_init(LLVidEncDSPContext *c)
{
c->diff_bytes = diff_bytes_c;
c->sub_median_pred = sub_median_pred_c;
c->sub_left_predict = sub_left_predict_c;
#if ARCH_RISCV
ff_llvidencdsp_init_riscv(c);
#elif ARCH_X86
ff_llvidencdsp_init_x86(c);
#endif
}