FFmpeg
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 {
43  GSMParseContext *s = s1->priv_data;
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:
50  s->block_size = GSM_BLOCK_SIZE;
51  s->duration = GSM_FRAME_SIZE;
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 };
GSMParseContext::remaining
int remaining
Definition: gsm_parser.c:36
ff_parse_close
void ff_parse_close(AVCodecParserContext *s)
Definition: parser.c:284
GSMParseContext
Definition: gsm_parser.c:32
ParseContext
Definition: parser.h:28
GSM_FRAME_SIZE
#define GSM_FRAME_SIZE
Definition: gsm.h:30
avassert.h
s
#define s(width, name)
Definition: cbs_vp9.c:256
gsm.h
s1
#define s1
Definition: regdef.h:38
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
GSM_MS_BLOCK_SIZE
#define GSM_MS_BLOCK_SIZE
Definition: gsm.h:26
AVCodecContext::codec_id
enum AVCodecID codec_id
Definition: avcodec.h:436
NULL
#define NULL
Definition: coverity.c:32
AV_CODEC_ID_GSM
@ AV_CODEC_ID_GSM
as in Berlin toast format
Definition: codec_id.h:456
AVCodecParser::codec_ids
int codec_ids[7]
Definition: avcodec.h:2972
ff_gsm_parser
const AVCodecParser ff_gsm_parser
Definition: gsm_parser.c:86
ff_combine_frame
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:199
GSMParseContext::duration
int duration
Definition: gsm_parser.c:35
GSM_BLOCK_SIZE
#define GSM_BLOCK_SIZE
Definition: gsm.h:25
parser.h
gsm_parse
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
AVCodecParserContext
Definition: avcodec.h:2812
AV_CODEC_ID_GSM_MS
@ AV_CODEC_ID_GSM_MS
Definition: codec_id.h:468
AVCodecContext::block_align
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs.
Definition: avcodec.h:1083
AVCodecContext
main external API structure.
Definition: avcodec.h:426
GSMParseContext::block_size
int block_size
Definition: gsm_parser.c:34
END_NOT_FOUND
#define END_NOT_FOUND
Definition: parser.h:40
AVCodecParser
Definition: avcodec.h:2971
GSMParseContext::pc
ParseContext pc
Definition: gsm_parser.c:33