dca_parser.c
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1 /*
2  * DCA parser
3  * Copyright (C) 2004 Gildas Bazin
4  * Copyright (C) 2004 Benjamin Zores
5  * Copyright (C) 2006 Benjamin Larsson
6  * Copyright (C) 2007 Konstantin Shishkov
7  *
8  * This file is part of Libav.
9  *
10  * Libav is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2.1 of the License, or (at your option) any later version.
14  *
15  * Libav is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with Libav; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 
25 #include "parser.h"
26 #include "dca.h"
27 
28 typedef struct DCAParseContext {
30  uint32_t lastmarker;
31  int size;
32  int framesize;
33  int hd_pos;
35 
36 #define IS_MARKER(state, i, buf, buf_size) \
37  ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \
38  || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \
39  || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE)
40 
45 static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
46  int buf_size)
47 {
48  int start_found, i;
49  uint32_t state;
50  ParseContext *pc = &pc1->pc;
51 
52  start_found = pc->frame_start_found;
53  state = pc->state;
54 
55  i = 0;
56  if (!start_found) {
57  for (i = 0; i < buf_size; i++) {
58  state = (state << 8) | buf[i];
59  if (IS_MARKER(state, i, buf, buf_size)) {
60  if (pc1->lastmarker && state == pc1->lastmarker) {
61  start_found = 1;
62  break;
63  } else if (!pc1->lastmarker) {
64  start_found = 1;
65  pc1->lastmarker = state;
66  break;
67  }
68  }
69  }
70  }
71  if (start_found) {
72  for (; i < buf_size; i++) {
73  pc1->size++;
74  state = (state << 8) | buf[i];
75  if (state == DCA_HD_MARKER && !pc1->hd_pos)
76  pc1->hd_pos = pc1->size;
77  if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) {
78  if(pc1->framesize > pc1->size)
79  continue;
80  if(!pc1->framesize){
81  pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size;
82  }
83  pc->frame_start_found = 0;
84  pc->state = -1;
85  pc1->size = 0;
86  return i - 3;
87  }
88  }
89  }
90  pc->frame_start_found = start_found;
91  pc->state = state;
92  return END_NOT_FOUND;
93 }
94 
96 {
97  DCAParseContext *pc1 = s->priv_data;
98 
99  pc1->lastmarker = 0;
100  return 0;
101 }
102 
104  AVCodecContext * avctx,
105  const uint8_t ** poutbuf, int *poutbuf_size,
106  const uint8_t * buf, int buf_size)
107 {
108  DCAParseContext *pc1 = s->priv_data;
109  ParseContext *pc = &pc1->pc;
110  int next;
111 
113  next = buf_size;
114  } else {
115  next = dca_find_frame_end(pc1, buf, buf_size);
116 
117  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
118  *poutbuf = NULL;
119  *poutbuf_size = 0;
120  return buf_size;
121  }
122  }
123  *poutbuf = buf;
124  *poutbuf_size = buf_size;
125  return next;
126 }
127 
129  .codec_ids = { CODEC_ID_DTS },
130  .priv_data_size = sizeof(DCAParseContext),
131  .parser_init = dca_parse_init,
132  .parser_parse = dca_parse,
133  .parser_close = ff_parse_close,
134 };