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dpx_parser.c
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1 /*
2  * DPX parser
3  * Copyright (c) 2013 Paul B Mahol
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * DPX parser
25  */
26 
27 #include "libavutil/bswap.h"
28 #include "libavutil/common.h"
29 
30 #include "parser.h"
31 
32 typedef struct DPXParseContext {
34  uint32_t index;
35  uint32_t fsize;
36  uint32_t remaining_size;
37  int is_be;
39 
41  const uint8_t **poutbuf, int *poutbuf_size,
42  const uint8_t *buf, int buf_size)
43 {
44  DPXParseContext *d = s->priv_data;
45  uint32_t state = d->pc.state;
46  int next = END_NOT_FOUND;
47  int i = 0;
48 
50 
51  *poutbuf_size = 0;
52  if (buf_size == 0)
53  next = 0;
54 
55  if (!d->pc.frame_start_found) {
56  for (; i < buf_size; i++) {
57  state = (state << 8) | buf[i];
58  if (state == MKBETAG('S','D','P','X') ||
59  state == MKTAG('S','D','P','X')) {
60  d->pc.frame_start_found = 1;
61  d->is_be = state == MKBETAG('S','D','P','X');
62  d->index = 0;
63  break;
64  }
65  }
66  d->pc.state = state;
67  } else {
68  if (d->remaining_size) {
69  i = FFMIN(d->remaining_size, buf_size);
70  d->remaining_size -= i;
71  if (d->remaining_size)
72  goto flush;
73  }
74  }
75 
76  for (; d->pc.frame_start_found && i < buf_size; i++) {
77  d->pc.state = (d->pc.state << 8) | buf[i];
78  d->index++;
79  if (d->index == 17) {
80  d->fsize = d->is_be ? d->pc.state : av_bswap32(d->pc.state);
81  if (d->fsize <= 1664) {
82  d->pc.frame_start_found = 0;
83  goto flush;
84  }
85  if (d->fsize > buf_size - i + 19)
86  d->remaining_size = d->fsize - buf_size + i - 19;
87  else
88  i += d->fsize - 19;
89 
90  break;
91  } else if (d->index > 17) {
92  if (d->pc.state == MKBETAG('S','D','P','X') ||
93  d->pc.state == MKTAG('S','D','P','X')) {
94  next = i - 3;
95  break;
96  }
97  }
98  }
99 
100 flush:
101  if (ff_combine_frame(&d->pc, next, &buf, &buf_size) < 0)
102  return buf_size;
103 
104  d->pc.frame_start_found = 0;
105 
106  *poutbuf = buf;
107  *poutbuf_size = buf_size;
108  return next;
109 }
110 
112  .codec_ids = { AV_CODEC_ID_DPX },
113  .priv_data_size = sizeof(DPXParseContext),
114  .parser_parse = dpx_parse,
115  .parser_close = ff_parse_close,
116 };
const char * s
Definition: avisynth_c.h:768
static void flush(AVCodecContext *avctx)
int codec_ids[5]
Definition: avcodec.h:5109
int frame_start_found
Definition: parser.h:34
uint8_t
static struct @281 state
uint32_t index
Definition: dpx_parser.c:34
uint32_t fsize
Definition: dpx_parser.c:35
int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
Combine the (truncated) bitstream to a complete frame.
Definition: parser.c:251
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:329
#define FFMIN(a, b)
Definition: common.h:96
uint32_t remaining_size
Definition: dpx_parser.c:36
#define av_bswap32
Definition: bswap.h:33
main external API structure.
Definition: avcodec.h:1502
void * buf
Definition: avisynth_c.h:690
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
byte swapping routines
#define END_NOT_FOUND
Definition: parser.h:40
common internal and external API header
#define MKBETAG(a, b, c, d)
Definition: common.h:367
static int dpx_parse(AVCodecParserContext *s, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: dpx_parser.c:40
AVCodecParser ff_dpx_parser
Definition: dpx_parser.c:111
#define MKTAG(a, b, c, d)
Definition: common.h:366
ParseContext pc
Definition: dpx_parser.c:33