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gsm_parser.c
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1 /*
2  * Copyright (c) 2012 Justin Ruggles
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  * GSM audio parser
24  *
25  * Splits packets into individual blocks.
26  */
27 
28 #include "libavutil/avassert.h"
29 #include "parser.h"
30 #include "gsm.h"
31 
32 typedef struct GSMParseContext {
35  int duration;
36  int remaining;
38 
40  const uint8_t **poutbuf, int *poutbuf_size,
41  const uint8_t *buf, int buf_size)
42 {
44  ParseContext *pc = &s->pc;
45  int next;
46 
47  if (!s->block_size) {
48  switch (avctx->codec_id) {
49  case AV_CODEC_ID_GSM:
52  break;
53  case AV_CODEC_ID_GSM_MS:
54  s->block_size = avctx->block_align ? avctx->block_align
56  s->duration = GSM_FRAME_SIZE * 2;
57  break;
58  default:
59  av_assert0(0);
60  }
61  }
62 
63  if (!s->remaining)
64  s->remaining = s->block_size;
65  if (s->remaining <= buf_size) {
66  next = s->remaining;
67  s->remaining = 0;
68  } else {
69  next = END_NOT_FOUND;
70  s->remaining -= buf_size;
71  }
72 
73  if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
74  *poutbuf = NULL;
75  *poutbuf_size = 0;
76  return buf_size;
77  }
78 
79  s1->duration = s->duration;
80 
81  *poutbuf = buf;
82  *poutbuf_size = buf_size;
83  return next;
84 }
85 
88  .priv_data_size = sizeof(GSMParseContext),
89  .parser_parse = gsm_parse,
90  .parser_close = ff_parse_close,
91 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
#define GSM_FRAME_SIZE
Definition: gsm.h:30
ParseContext pc
Definition: gsm_parser.c:33
AVCodecParser ff_gsm_parser
Definition: gsm_parser.c:86
int codec_ids[5]
Definition: avcodec.h:5071
int duration
Duration of the current frame.
Definition: avcodec.h:5025
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:2437
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
uint8_t
#define GSM_MS_BLOCK_SIZE
Definition: gsm.h:26
#define GSM_BLOCK_SIZE
Definition: gsm.h:25
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:245
simple assert() macros that are a bit more flexible than ISO C assert().
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:321
static int gsm_parse(AVCodecParserContext *s1, AVCodecContext *avctx, const uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size)
Definition: gsm_parser.c:39
enum AVCodecID codec_id
Definition: avcodec.h:1656
main external API structure.
Definition: avcodec.h:1639
void * buf
Definition: avisynth_c.h:553
#define s1
Definition: regdef.h:38
#define END_NOT_FOUND
Definition: parser.h:40
as in Berlin toast format
Definition: avcodec.h:527