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  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.  
  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.     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.  
  71. static int ilbc_read_header(AVFormatContext *s)
  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);
  82.     st->codec->codec_id = AV_CODEC_ID_ILBC;
  83.     st->codec->sample_rate = 8000;
  84.     st->codec->channels = 1;
  85.     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  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.  
  102. static int ilbc_read_packet(AVFormatContext *s,
  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.  
  122. AVInputFormat ff_ilbc_demuxer = {
  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.  
  131. AVOutputFormat ff_ilbc_muxer = {
  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. };
  141.