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/*
* HEVC common code
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <string.h>
#include "config.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#include "hevc.h"
/* FIXME: This is adapted from ff_h264_decode_nal, avoiding duplication
* between these functions would be nice. */
int ff_hevc_extract_rbsp(const uint8_t *src, int length,
HEVCNAL *nal)
{
int i, si, di;
uint8_t *dst;
#define STARTCODE_TEST \
if (i + 2 < length && src[i + 1] == 0 && src[i + 2] <= 3) { \
if (src[i + 2] != 3) { \
/* startcode, so we must be past the end */ \
length = i; \
} \
break; \
}
#if HAVE_FAST_UNALIGNED
#define FIND_FIRST_ZERO \
if (i > 0 && !src[i]) \
i--; \
while (src[i]) \
i++
#if HAVE_FAST_64BIT
for (i = 0; i + 1 < length; i += 9) {
if (!((~AV_RN64A(src + i) &
(AV_RN64A(src + i) - 0x0100010001000101ULL)) &
0x8000800080008080ULL))
continue;
FIND_FIRST_ZERO;
STARTCODE_TEST;
i -= 7;
}
#else
for (i = 0; i + 1 < length; i += 5) {
if (!((~AV_RN32A(src + i) &
(AV_RN32A(src + i) - 0x01000101U)) &
0x80008080U))
continue;
FIND_FIRST_ZERO;
STARTCODE_TEST;
i -= 3;
}
#endif /* HAVE_FAST_64BIT */
#else
for (i = 0; i + 1 < length; i += 2) {
if (src[i])
continue;
if (i > 0 && src[i - 1] == 0)
i--;
STARTCODE_TEST;
}
#endif /* HAVE_FAST_UNALIGNED */
if (i >= length - 1) { // no escaped 0
nal->data =
nal->raw_data = src;
nal->size =
nal->raw_size = length;
return length;
}
av_fast_malloc(&nal->rbsp_buffer, &nal->rbsp_buffer_size,
length + FF_INPUT_BUFFER_PADDING_SIZE);
if (!nal->rbsp_buffer)
return AVERROR(ENOMEM);
dst = nal->rbsp_buffer;
memcpy(dst, src, i);
si = di = i;
while (si + 2 < length) {
// remove escapes (very rare 1:2^22)
if (src[si + 2] > 3) {
dst[di++] = src[si++];
dst[di++] = src[si++];
} else if (src[si] == 0 && src[si + 1] == 0) {
if (src[si + 2] == 3) { // escape
dst[di++] = 0;
dst[di++] = 0;
si += 3;
continue;
} else // next start code
goto nsc;
}
dst[di++] = src[si++];
}
while (si < length)
dst[di++] = src[si++];
nsc:
memset(dst + di, 0, FF_INPUT_BUFFER_PADDING_SIZE);
nal->data = dst;
nal->size = di;
nal->raw_data = src;
nal->raw_size = si;
return si;
}
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