FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
ilbc.c
Go to the documentation of this file.
1 /*
2  * iLBC storage file format
3  * Copyright (c) 2012 Martin Storsjo
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 #include "avformat.h"
23 #include "internal.h"
24 
25 static const char mode20_header[] = "#!iLBC20\n";
26 static const char mode30_header[] = "#!iLBC30\n";
27 
29 {
30  AVIOContext *pb = s->pb;
31  AVCodecContext *enc;
32 
33  if (s->nb_streams != 1) {
34  av_log(s, AV_LOG_ERROR, "Unsupported number of streams\n");
35  return AVERROR(EINVAL);
36  }
37  enc = s->streams[0]->codec;
38 
39  if (enc->codec_id != AV_CODEC_ID_ILBC) {
40  av_log(s, AV_LOG_ERROR, "Unsupported codec\n");
41  return AVERROR(EINVAL);
42  }
43 
44  if (enc->block_align == 50) {
45  avio_write(pb, mode30_header, sizeof(mode30_header) - 1);
46  } else if (enc->block_align == 38) {
47  avio_write(pb, mode20_header, sizeof(mode20_header) - 1);
48  } else {
49  av_log(s, AV_LOG_ERROR, "Unsupported mode\n");
50  return AVERROR(EINVAL);
51  }
52  avio_flush(pb);
53  return 0;
54 }
55 
57 {
58  avio_write(s->pb, pkt->data, pkt->size);
59  return 0;
60 }
61 
62 static int ilbc_probe(AVProbeData *p)
63 {
64  // Only check for "#!iLBC" which matches both formats
65  if (!memcmp(p->buf, mode20_header, 6))
66  return AVPROBE_SCORE_MAX;
67  else
68  return 0;
69 }
70 
72 {
73  AVIOContext *pb = s->pb;
74  AVStream *st;
75  uint8_t header[9];
76 
77  avio_read(pb, header, 9);
78 
79  st = avformat_new_stream(s, NULL);
80  if (!st)
81  return AVERROR(ENOMEM);
83  st->codec->sample_rate = 8000;
84  st->codec->channels = 1;
86  st->start_time = 0;
87  avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
88  if (!memcmp(header, mode20_header, sizeof(mode20_header) - 1)) {
89  st->codec->block_align = 38;
90  st->codec->bit_rate = 15200;
91  } else if (!memcmp(header, mode30_header, sizeof(mode30_header) - 1)) {
92  st->codec->block_align = 50;
93  st->codec->bit_rate = 13333;
94  } else {
95  av_log(s, AV_LOG_ERROR, "Unrecognized iLBC file header\n");
96  return AVERROR_INVALIDDATA;
97  }
98 
99  return 0;
100 }
101 
103  AVPacket *pkt)
104 {
105  AVCodecContext *enc = s->streams[0]->codec;
106  int ret;
107 
108  if ((ret = av_new_packet(pkt, enc->block_align)) < 0)
109  return ret;
110 
111  pkt->stream_index = 0;
112  pkt->pos = avio_tell(s->pb);
113  pkt->duration = enc->block_align == 38 ? 160 : 240;
114  if ((ret = avio_read(s->pb, pkt->data, enc->block_align)) != enc->block_align) {
115  av_free_packet(pkt);
116  return ret < 0 ? ret : AVERROR(EIO);
117  }
118 
119  return 0;
120 }
121 
123  .name = "ilbc",
124  .long_name = NULL_IF_CONFIG_SMALL("iLBC storage"),
125  .read_probe = ilbc_probe,
126  .read_header = ilbc_read_header,
127  .read_packet = ilbc_read_packet,
128  .flags = AVFMT_GENERIC_INDEX,
129 };
130 
132  .name = "ilbc",
133  .long_name = NULL_IF_CONFIG_SMALL("iLBC storage"),
134  .mime_type = "audio/iLBC",
135  .extensions = "lbc",
136  .audio_codec = AV_CODEC_ID_ILBC,
137  .write_header = ilbc_write_header,
138  .write_packet = ilbc_write_packet,
139  .flags = AVFMT_NOTIMESTAMPS,
140 };