3 * Copyright (c) 2001 ffmpeg project
5 * This file is part of FFmpeg.
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.
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.
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
23 Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
25 Only mono files are supported.
29 #include "libavutil/avassert.h"
30 #include "libavutil/channel_layout.h"
34 static const char AMR_header[] = "#!AMR\n";
35 static const char AMRWB_header[] = "#!AMR-WB\n";
38 static int amr_write_header(AVFormatContext *s)
40 AVIOContext *pb = s->pb;
41 AVCodecContext *enc = s->streams[0]->codec;
45 if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
46 avio_write(pb, AMR_header, sizeof(AMR_header) - 1); /* magic number */
47 } else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {
48 avio_write(pb, AMRWB_header, sizeof(AMRWB_header) - 1); /* magic number */
56 static int amr_write_packet(AVFormatContext *s, AVPacket *pkt)
58 avio_write(s->pb, pkt->data, pkt->size);
62 #endif /* CONFIG_AMR_MUXER */
64 static int amr_probe(AVProbeData *p)
66 // Only check for "#!AMR" which could be amr-wb, amr-nb.
67 // This will also trigger multichannel files: "#!AMR_MC1.0\n" and
68 // "#!AMR-WB_MC1.0\n" (not supported)
70 if (!memcmp(p->buf, AMR_header, 5))
71 return AVPROBE_SCORE_MAX;
77 static int amr_read_header(AVFormatContext *s)
79 AVIOContext *pb = s->pb;
83 avio_read(pb, header, 6);
85 st = avformat_new_stream(s, NULL);
87 return AVERROR(ENOMEM);
88 if (memcmp(header, AMR_header, 6)) {
89 avio_read(pb, header + 6, 3);
90 if (memcmp(header, AMRWB_header, 9)) {
94 st->codec->codec_tag = MKTAG('s', 'a', 'w', 'b');
95 st->codec->codec_id = AV_CODEC_ID_AMR_WB;
96 st->codec->sample_rate = 16000;
98 st->codec->codec_tag = MKTAG('s', 'a', 'm', 'r');
99 st->codec->codec_id = AV_CODEC_ID_AMR_NB;
100 st->codec->sample_rate = 8000;
102 st->codec->channels = 1;
103 st->codec->channel_layout = AV_CH_LAYOUT_MONO;
104 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
105 avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
110 static int amr_read_packet(AVFormatContext *s, AVPacket *pkt)
112 AVCodecContext *enc = s->streams[0]->codec;
113 int read, size = 0, toc, mode;
114 int64_t pos = avio_tell(s->pb);
116 if (url_feof(s->pb)) {
120 // FIXME this is wrong, this should rather be in a AVParset
121 toc = avio_r8(s->pb);
122 mode = (toc >> 3) & 0x0F;
124 if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
125 static const uint8_t packed_size[16] = {
126 12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
129 size = packed_size[mode] + 1;
130 } else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {
131 static const uint8_t packed_size[16] = {
132 18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1
135 size = packed_size[mode];
140 if (!size || av_new_packet(pkt, size))
143 /* Both AMR formats have 50 frames per second */
144 s->streams[0]->codec->bit_rate = size*8*50;
146 pkt->stream_index = 0;
149 pkt->duration = enc->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;
150 read = avio_read(s->pb, pkt->data + 1, size - 1);
152 if (read != size - 1) {
160 #if CONFIG_AMR_DEMUXER
161 AVInputFormat ff_amr_demuxer = {
163 .long_name = NULL_IF_CONFIG_SMALL("3GPP AMR"),
164 .read_probe = amr_probe,
165 .read_header = amr_read_header,
166 .read_packet = amr_read_packet,
167 .flags = AVFMT_GENERIC_INDEX,
172 AVOutputFormat ff_amr_muxer = {
174 .long_name = NULL_IF_CONFIG_SMALL("3GPP AMR"),
175 .mime_type = "audio/amr",
177 .audio_codec = AV_CODEC_ID_AMR_NB,
178 .video_codec = AV_CODEC_ID_NONE,
179 .write_header = amr_write_header,
180 .write_packet = amr_write_packet,