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tak_parser.c
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1 /*
2  * TAK parser
3  * Copyright (c) 2012 Michael Niedermayer
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  * TAK parser
25  **/
26 
27 #include "tak.h"
28 #include "parser.h"
29 
30 typedef struct TAKParseContext {
33  int index;
35 
37 {
39  return 0;
40 }
41 
43  const uint8_t **poutbuf, int *poutbuf_size,
44  const uint8_t *buf, int buf_size)
45 {
47  ParseContext *pc = &t->pc;
48  int next = END_NOT_FOUND;
49  GetBitContext gb;
50  int consumed = 0;
51  int needed = buf_size ? TAK_MAX_FRAME_HEADER_BYTES : 8;
52 
54  TAKStreamInfo ti;
55  init_get_bits(&gb, buf, buf_size);
56  if (!ff_tak_decode_frame_header(avctx, &gb, &ti, 127))
58  : t->ti.frame_samples;
59  *poutbuf = buf;
60  *poutbuf_size = buf_size;
61  return buf_size;
62  }
63 
64  while (buf_size || t->index + needed <= pc->index) {
65  if (buf_size && t->index + TAK_MAX_FRAME_HEADER_BYTES > pc->index) {
66  int tmp_buf_size = FFMIN(2 * TAK_MAX_FRAME_HEADER_BYTES,
67  buf_size);
68  const uint8_t *tmp_buf = buf;
69 
70  if (ff_combine_frame(pc, END_NOT_FOUND, &tmp_buf, &tmp_buf_size) != -1)
71  return AVERROR(ENOMEM);
72  consumed += tmp_buf_size;
73  buf += tmp_buf_size;
74  buf_size -= tmp_buf_size;
75  }
76 
77  for (; t->index + needed <= pc->index; t->index++) {
78  if (pc->buffer[ t->index ] == 0xFF &&
79  pc->buffer[ t->index + 1 ] == 0xA0) {
80  TAKStreamInfo ti;
81 
82  init_get_bits(&gb, pc->buffer + t->index,
83  8 * (pc->index - t->index));
84  if (!ff_tak_decode_frame_header(avctx, &gb,
85  pc->frame_start_found ? &ti : &t->ti, 127) &&
86  !ff_tak_check_crc(pc->buffer + t->index,
87  get_bits_count(&gb) / 8)) {
88  if (!pc->frame_start_found) {
89  pc->frame_start_found = 1;
92  t->ti.frame_samples;
94  } else {
95  pc->frame_start_found = 0;
96  next = t->index - pc->index;
97  t->index = 0;
98  goto found;
99  }
100  }
101  }
102  }
103  }
104 found:
105 
106  if (consumed && !buf_size && next == END_NOT_FOUND ||
107  ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
108  *poutbuf = NULL;
109  *poutbuf_size = 0;
110  return buf_size + consumed;
111  }
112 
113  if (next != END_NOT_FOUND) {
114  next += consumed;
115  pc->overread = FFMAX(0, -next);
116  }
117 
118  *poutbuf = buf;
119  *poutbuf_size = buf_size;
120  return next;
121 }
122 
124  .codec_ids = { AV_CODEC_ID_TAK },
125  .priv_data_size = sizeof(TAKParseContext),
126  .parser_init = tak_init,
127  .parser_parse = tak_parse,
128  .parser_close = ff_parse_close,
129 };