FFmpeg
startcode.c
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1 /*
2  * Copyright (c) 2003-2010 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * Accelerated start code search function for start codes common to
24  * MPEG-1/2/4 video, VC-1, H.264/5
25  * @author Michael Niedermayer <michaelni@gmx.at>
26  */
27 
28 #include "startcode.h"
29 #include "config.h"
30 
32 {
33  int i = 0;
34 #if HAVE_FAST_UNALIGNED
35  /* we check i < size instead of i + 3 / 7 because it is
36  * simpler and there must be AV_INPUT_BUFFER_PADDING_SIZE
37  * bytes at the end.
38  */
39 #if HAVE_FAST_64BIT
40  while (i < size &&
41  !((~*(const uint64_t *)(buf + i) &
42  (*(const uint64_t *)(buf + i) - 0x0101010101010101ULL)) &
43  0x8080808080808080ULL))
44  i += 8;
45 #else
46  while (i < size &&
47  !((~*(const uint32_t *)(buf + i) &
48  (*(const uint32_t *)(buf + i) - 0x01010101U)) &
49  0x80808080U))
50  i += 4;
51 #endif
52 #endif
53  for (; i < size; i++)
54  if (!buf[i])
55  break;
56  return i;
57 }
uint8_t
ptrdiff_t size
Definition: opengl_enc.c:100
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
Accelerated start code search function for start codes common to MPEG-1/2/4 video, VC-1, H.264/5.
int ff_startcode_find_candidate_c(const uint8_t *buf, int size)
Definition: startcode.c:31
void * buf
Definition: avisynth_c.h:766