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libavformat/amr.c

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00001 /*
00002  * amr file format
00003  * Copyright (c) 2001 ffmpeg project
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 /*
00023 Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
00024 
00025 Only mono files are supported.
00026 
00027 */
00028 #include "avformat.h"
00029 
00030 static const char AMR_header [] = "#!AMR\n";
00031 static const char AMRWB_header [] = "#!AMR-WB\n";
00032 
00033 #if CONFIG_AMR_MUXER
00034 static int amr_write_header(AVFormatContext *s)
00035 {
00036     ByteIOContext *pb = s->pb;
00037     AVCodecContext *enc = s->streams[0]->codec;
00038 
00039     s->priv_data = NULL;
00040 
00041     if (enc->codec_id == CODEC_ID_AMR_NB)
00042     {
00043         put_tag(pb, AMR_header);       /* magic number */
00044     }
00045     else if(enc->codec_id == CODEC_ID_AMR_WB)
00046     {
00047         put_tag(pb, AMRWB_header);       /* magic number */
00048     }
00049     else
00050     {
00051         return -1;
00052     }
00053     put_flush_packet(pb);
00054     return 0;
00055 }
00056 
00057 static int amr_write_packet(AVFormatContext *s, AVPacket *pkt)
00058 {
00059     put_buffer(s->pb, pkt->data, pkt->size);
00060     put_flush_packet(s->pb);
00061     return 0;
00062 }
00063 #endif /* CONFIG_AMR_MUXER */
00064 
00065 static int amr_probe(AVProbeData *p)
00066 {
00067     //Only check for "#!AMR" which could be amr-wb, amr-nb.
00068     //This will also trigger multichannel files: "#!AMR_MC1.0\n" and
00069     //"#!AMR-WB_MC1.0\n" (not supported)
00070 
00071     if(memcmp(p->buf,AMR_header,5)==0)
00072         return AVPROBE_SCORE_MAX;
00073     else
00074         return 0;
00075 }
00076 
00077 /* amr input */
00078 static int amr_read_header(AVFormatContext *s,
00079                            AVFormatParameters *ap)
00080 {
00081     ByteIOContext *pb = s->pb;
00082     AVStream *st;
00083     uint8_t header[9];
00084 
00085     get_buffer(pb, header, 6);
00086 
00087     st = av_new_stream(s, 0);
00088     if (!st)
00089     {
00090         return AVERROR(ENOMEM);
00091     }
00092     if(memcmp(header,AMR_header,6)!=0)
00093     {
00094         get_buffer(pb, header+6, 3);
00095         if(memcmp(header,AMRWB_header,9)!=0)
00096         {
00097             return -1;
00098         }
00099 
00100         st->codec->codec_tag = MKTAG('s', 'a', 'w', 'b');
00101         st->codec->codec_id = CODEC_ID_AMR_WB;
00102         st->codec->sample_rate = 16000;
00103     }
00104     else
00105     {
00106         st->codec->codec_tag = MKTAG('s', 'a', 'm', 'r');
00107         st->codec->codec_id = CODEC_ID_AMR_NB;
00108         st->codec->sample_rate = 8000;
00109     }
00110     st->codec->channels = 1;
00111     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
00112     av_set_pts_info(st, 64, 1, st->codec->sample_rate);
00113 
00114     return 0;
00115 }
00116 
00117 static int amr_read_packet(AVFormatContext *s,
00118                           AVPacket *pkt)
00119 {
00120     AVCodecContext *enc = s->streams[0]->codec;
00121     int read, size = 0, toc, mode;
00122 
00123     if (url_feof(s->pb))
00124     {
00125         return AVERROR(EIO);
00126     }
00127 
00128 //FIXME this is wrong, this should rather be in a AVParset
00129     toc=get_byte(s->pb);
00130     mode = (toc >> 3) & 0x0F;
00131 
00132     if (enc->codec_id == CODEC_ID_AMR_NB)
00133     {
00134         static const uint8_t packed_size[16] = {12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0};
00135 
00136         size=packed_size[mode]+1;
00137     }
00138     else if(enc->codec_id == CODEC_ID_AMR_WB)
00139     {
00140         static uint8_t packed_size[16] = {18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1};
00141 
00142         size=packed_size[mode];
00143     }
00144     else
00145     {
00146         assert(0);
00147     }
00148 
00149     if ( (size==0) || av_new_packet(pkt, size))
00150     {
00151         return AVERROR(EIO);
00152     }
00153 
00154     pkt->stream_index = 0;
00155     pkt->pos= url_ftell(s->pb);
00156     pkt->data[0]=toc;
00157     pkt->duration= enc->codec_id == CODEC_ID_AMR_NB ? 160 : 320;
00158     read = get_buffer(s->pb, pkt->data+1, size-1);
00159 
00160     if (read != size-1)
00161     {
00162         av_free_packet(pkt);
00163         return AVERROR(EIO);
00164     }
00165 
00166     return 0;
00167 }
00168 
00169 #if CONFIG_AMR_DEMUXER
00170 AVInputFormat amr_demuxer = {
00171     "amr",
00172     NULL_IF_CONFIG_SMALL("3GPP AMR file format"),
00173     0, /*priv_data_size*/
00174     amr_probe,
00175     amr_read_header,
00176     amr_read_packet,
00177     NULL,
00178 };
00179 #endif
00180 
00181 #if CONFIG_AMR_MUXER
00182 AVOutputFormat amr_muxer = {
00183     "amr",
00184     NULL_IF_CONFIG_SMALL("3GPP AMR file format"),
00185     "audio/amr",
00186     "amr",
00187     0,
00188     CODEC_ID_AMR_NB,
00189     CODEC_ID_NONE,
00190     amr_write_header,
00191     amr_write_packet,
00192 };
00193 #endif

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