libavformat/amr.c

   1 /*
   2  * amr file format
   3  * Copyright (c) 2001 FFmpeg project
   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 /*
  23 Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
  24
  25 Only mono files are supported.
  26
  27 */
  28
  29 #include "libavutil/channel_layout.h"
  30 #include "avformat.h"
  31 #include "internal.h"
  32
  33 typedef struct {
  34     uint64_t cumulated_size;
  35     uint64_t block_count;
  36 } AMRContext;
  37
  38 static const char AMR_header[]   = "#!AMR\n";
  39 static const char AMRWB_header[] = "#!AMR-WB\n";
  40
  41 #if CONFIG_AMR_MUXER
  42 static int amr_write_header(AVFormatContext *s)
  43 {
  44     AVIOContext    *pb  = s->pb;
  45     AVCodecParameters *par = s->streams[0]->codecpar;
  46
  47     s->priv_data = NULL;
  48
  49     if (par->codec_id == AV_CODEC_ID_AMR_NB) {
  50         avio_write(pb, AMR_header,   sizeof(AMR_header)   - 1); /* magic number */
  51     } else if (par->codec_id == AV_CODEC_ID_AMR_WB) {
  52         avio_write(pb, AMRWB_header, sizeof(AMRWB_header) - 1); /* magic number */
  53     } else {
  54         return -1;
  55     }
  56     avio_flush(pb);
  57     return 0;
  58 }
  59
  60 static int amr_write_packet(AVFormatContext *s, AVPacket *pkt)
  61 {
  62     avio_write(s->pb, pkt->data, pkt->size);
  63     return 0;
  64 }
  65 #endif /* CONFIG_AMR_MUXER */
  66
  67 static int amr_probe(AVProbeData *p)
  68 {
  69     // Only check for "#!AMR" which could be amr-wb, amr-nb.
  70     // This will also trigger multichannel files: "#!AMR_MC1.0\n" and
  71     // "#!AMR-WB_MC1.0\n" (not supported)
  72
  73     if (!memcmp(p->buf, AMR_header, 5))
  74         return AVPROBE_SCORE_MAX;
  75     else
  76         return 0;
  77 }
  78
  79 /* amr input */
  80 static int amr_read_header(AVFormatContext *s)
  81 {
  82     AVIOContext *pb = s->pb;
  83     AVStream *st;
  84     uint8_t header[9];
  85
  86     if (avio_read(pb, header, 6) != 6)
  87         return AVERROR_INVALIDDATA;
  88
  89     st = avformat_new_stream(s, NULL);
  90     if (!st)
  91         return AVERROR(ENOMEM);
  92     if (memcmp(header, AMR_header, 6)) {
  93         if (avio_read(pb, header + 6, 3) != 3)
  94             return AVERROR_INVALIDDATA;
  95         if (memcmp(header, AMRWB_header, 9)) {
  96             return -1;
  97         }
  98
  99         st->codecpar->codec_tag   = MKTAG('s', 'a', 'w', 'b');
 100         st->codecpar->codec_id    = AV_CODEC_ID_AMR_WB;
 101         st->codecpar->sample_rate = 16000;
 102     } else {
 103         st->codecpar->codec_tag   = MKTAG('s', 'a', 'm', 'r');
 104         st->codecpar->codec_id    = AV_CODEC_ID_AMR_NB;
 105         st->codecpar->sample_rate = 8000;
 106     }
 107     st->codecpar->channels   = 1;
 108     st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
 109     st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
 110     avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
 111
 112     return 0;
 113 }
 114
 115 static int amr_read_packet(AVFormatContext *s, AVPacket *pkt)
 116 {
 117     AVCodecParameters *par = s->streams[0]->codecpar;
 118     int read, size = 0, toc, mode;
 119     int64_t pos = avio_tell(s->pb);
 120     AMRContext *amr = s->priv_data;
 121
 122     if (avio_feof(s->pb)) {
 123         return AVERROR(EIO);
 124     }
 125
 126     // FIXME this is wrong, this should rather be in an AVParser
 127     toc  = avio_r8(s->pb);
 128     mode = (toc >> 3) & 0x0F;
 129
 130     if (par->codec_id == AV_CODEC_ID_AMR_NB) {
 131         static const uint8_t packed_size[16] = {
 132             12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
 133         };
 134
 135         size = packed_size[mode] + 1;
 136     } else if (par->codec_id == AV_CODEC_ID_AMR_WB) {
 137         static const uint8_t packed_size[16] = {
 138             18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1
 139         };
 140
 141         size = packed_size[mode];
 142     }
 143
 144     if (!size || av_new_packet(pkt, size))
 145         return AVERROR(EIO);
 146
 147     if (amr->cumulated_size < UINT64_MAX - size) {
 148         amr->cumulated_size += size;
 149         /* Both AMR formats have 50 frames per second */
 150         s->streams[0]->codecpar->bit_rate = amr->cumulated_size / ++amr->block_count * 8 * 50;
 151     }
 152
 153     pkt->stream_index = 0;
 154     pkt->pos          = pos;
 155     pkt->data[0]      = toc;
 156     pkt->duration     = par->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;
 157     read              = avio_read(s->pb, pkt->data + 1, size - 1);
 158
 159     if (read != size - 1) {
 160         av_packet_unref(pkt);
 161         return AVERROR(EIO);
 162     }
 163
 164     return 0;
 165 }
 166
 167 #if CONFIG_AMR_DEMUXER
 168 AVInputFormat ff_amr_demuxer = {
 169     .name           = "amr",
 170     .long_name      = NULL_IF_CONFIG_SMALL("3GPP AMR"),
 171     .priv_data_size = sizeof(AMRContext),
 172     .read_probe     = amr_probe,
 173     .read_header    = amr_read_header,
 174     .read_packet    = amr_read_packet,
 175     .flags          = AVFMT_GENERIC_INDEX,
 176 };
 177 #endif
 178
 179 #if CONFIG_AMR_MUXER
 180 AVOutputFormat ff_amr_muxer = {
 181     .name              = "amr",
 182     .long_name         = NULL_IF_CONFIG_SMALL("3GPP AMR"),
 183     .mime_type         = "audio/amr",
 184     .extensions        = "amr",
 185     .audio_codec       = AV_CODEC_ID_AMR_NB,
 186     .video_codec       = AV_CODEC_ID_NONE,
 187     .write_header      = amr_write_header,
 188     .write_packet      = amr_write_packet,
 189     .flags             = AVFMT_NOTIMESTAMPS,
 190 };
 191 #endif