3 * Copyright (c) 2001 ffmpeg project
5 * This file is part of Libav.
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.
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.
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
23 Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
25 Only mono files are supported.
31 static const char AMR_header[] = "#!AMR\n";
32 static const char AMRWB_header[] = "#!AMR-WB\n";
35 static int amr_write_header(AVFormatContext *s)
37 AVIOContext *pb = s->pb;
38 AVCodecContext *enc = s->streams[0]->codec;
42 if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
43 avio_write(pb, AMR_header, sizeof(AMR_header) - 1); /* magic number */
44 } else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {
45 avio_write(pb, AMRWB_header, sizeof(AMRWB_header) - 1); /* magic number */
53 static int amr_write_packet(AVFormatContext *s, AVPacket *pkt)
55 avio_write(s->pb, pkt->data, pkt->size);
59 #endif /* CONFIG_AMR_MUXER */
61 static int amr_probe(AVProbeData *p)
63 // Only check for "#!AMR" which could be amr-wb, amr-nb.
64 // This will also trigger multichannel files: "#!AMR_MC1.0\n" and
65 // "#!AMR-WB_MC1.0\n" (not supported)
67 if (!memcmp(p->buf, AMR_header, 5))
68 return AVPROBE_SCORE_MAX;
74 static int amr_read_header(AVFormatContext *s)
76 AVIOContext *pb = s->pb;
80 avio_read(pb, header, 6);
82 st = avformat_new_stream(s, NULL);
84 return AVERROR(ENOMEM);
85 if (memcmp(header, AMR_header, 6)) {
86 avio_read(pb, header + 6, 3);
87 if (memcmp(header, AMRWB_header, 9)) {
91 st->codec->codec_tag = MKTAG('s', 'a', 'w', 'b');
92 st->codec->codec_id = AV_CODEC_ID_AMR_WB;
93 st->codec->sample_rate = 16000;
95 st->codec->codec_tag = MKTAG('s', 'a', 'm', 'r');
96 st->codec->codec_id = AV_CODEC_ID_AMR_NB;
97 st->codec->sample_rate = 8000;
99 st->codec->channels = 1;
100 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
101 avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
106 static int amr_read_packet(AVFormatContext *s, AVPacket *pkt)
108 AVCodecContext *enc = s->streams[0]->codec;
109 int read, size = 0, toc, mode;
110 int64_t pos = avio_tell(s->pb);
112 if (s->pb->eof_reached) {
116 // FIXME this is wrong, this should rather be in a AVParset
117 toc = avio_r8(s->pb);
118 mode = (toc >> 3) & 0x0F;
120 if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
121 static const uint8_t packed_size[16] = {
122 12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
125 size = packed_size[mode] + 1;
126 } else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {
127 static const uint8_t packed_size[16] = {
128 18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1
131 size = packed_size[mode];
136 if (!size || av_new_packet(pkt, size))
139 /* Both AMR formats have 50 frames per second */
140 s->streams[0]->codec->bit_rate = size*8*50;
142 pkt->stream_index = 0;
145 pkt->duration = enc->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;
146 read = avio_read(s->pb, pkt->data + 1, size - 1);
148 if (read != size - 1) {
156 #if CONFIG_AMR_DEMUXER
157 AVInputFormat ff_amr_demuxer = {
159 .long_name = NULL_IF_CONFIG_SMALL("3GPP AMR"),
160 .read_probe = amr_probe,
161 .read_header = amr_read_header,
162 .read_packet = amr_read_packet,
163 .flags = AVFMT_GENERIC_INDEX,
168 AVOutputFormat ff_amr_muxer = {
170 .long_name = NULL_IF_CONFIG_SMALL("3GPP AMR"),
171 .mime_type = "audio/amr",
173 .audio_codec = AV_CODEC_ID_AMR_NB,
174 .video_codec = AV_CODEC_ID_NONE,
175 .write_header = amr_write_header,
176 .write_packet = amr_write_packet,