libavformat/ilbc.c

   1 /*
   2  * iLBC storage file format
   3  * Copyright (c) 2012 Martin Storsjo
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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
  28 static int ilbc_write_header(AVFormatContext *s)
  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
  56 static int ilbc_write_packet(AVFormatContext *s, AVPacket *pkt)
  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
  72 static int ilbc_read_header(AVFormatContext *s)
  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);
  83     st->codec->codec_id = AV_CODEC_ID_ILBC;
  84     st->codec->sample_rate = 8000;
  85     st->codec->channels = 1;
  86     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  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
 103 static int ilbc_read_packet(AVFormatContext *s,
 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
 123 AVInputFormat ff_ilbc_demuxer = {
 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
 132 AVOutputFormat ff_ilbc_muxer = {
 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 };