FFmpeg
 All Data Structures 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  avio_flush(s->pb);
60  return 0;
61 }
62 
63 static int ilbc_probe(AVProbeData *p)
64 {
65  // Only check for "#!iLBC" which matches both formats
66  if (!memcmp(p->buf, mode20_header, 6))
67  return AVPROBE_SCORE_MAX;
68  else
69  return 0;
70 }
71 
73 {
74  AVIOContext *pb = s->pb;
75  AVStream *st;
76  uint8_t header[9];
77 
78  avio_read(pb, header, 9);
79 
80  st = avformat_new_stream(s, NULL);
81  if (!st)
82  return AVERROR(ENOMEM);
84  st->codec->sample_rate = 8000;
85  st->codec->channels = 1;
87  st->start_time = 0;
88  avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
89  if (!memcmp(header, mode20_header, sizeof(mode20_header) - 1)) {
90  st->codec->block_align = 38;
91  st->codec->bit_rate = 15200;
92  } else if (!memcmp(header, mode30_header, sizeof(mode30_header) - 1)) {
93  st->codec->block_align = 50;
94  st->codec->bit_rate = 13333;
95  } else {
96  av_log(s, AV_LOG_ERROR, "Unrecognized iLBC file header\n");
97  return AVERROR_INVALIDDATA;
98  }
99 
100  return 0;
101 }
102 
104  AVPacket *pkt)
105 {
106  AVCodecContext *enc = s->streams[0]->codec;
107  int ret;
108 
109  if ((ret = av_new_packet(pkt, enc->block_align)) < 0)
110  return ret;
111 
112  pkt->stream_index = 0;
113  pkt->pos = avio_tell(s->pb);
114  pkt->duration = enc->block_align == 38 ? 160 : 240;
115  if ((ret = avio_read(s->pb, pkt->data, enc->block_align)) != enc->block_align) {
116  av_free_packet(pkt);
117  return ret < 0 ? ret : AVERROR(EIO);
118  }
119 
120  return 0;
121 }
122 
124  .name = "ilbc",
125  .long_name = NULL_IF_CONFIG_SMALL("iLBC storage"),
126  .read_probe = ilbc_probe,
127  .read_header = ilbc_read_header,
128  .read_packet = ilbc_read_packet,
129  .flags = AVFMT_GENERIC_INDEX,
130 };
131 
133  .name = "ilbc",
134  .long_name = NULL_IF_CONFIG_SMALL("iLBC storage"),
135  .mime_type = "audio/iLBC",
136  .extensions = "lbc",
137  .audio_codec = AV_CODEC_ID_ILBC,
138  .write_header = ilbc_write_header,
139  .write_packet = ilbc_write_packet,
140  .flags = AVFMT_NOTIMESTAMPS,
141 };