3 * Copyright (c) 2003 Fabrice Bellard
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 #include "avio_internal.h"
27 #include "libavutil/avstring.h"
28 #include "libavcodec/mpegaudio.h"
29 #include "libavcodec/mpegaudiodata.h"
30 #include "libavcodec/mpegaudiodecheader.h"
31 #include "libavutil/intreadwrite.h"
32 #include "libavutil/opt.h"
33 #include "libavutil/dict.h"
35 static int id3v1_set_string(AVFormatContext *s, const char *key,
36 uint8_t *buf, int buf_size)
38 AVDictionaryEntry *tag;
39 if ((tag = av_dict_get(s->metadata, key, NULL, 0)))
40 av_strlcpy(buf, tag->value, buf_size);
44 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
46 AVDictionaryEntry *tag;
49 memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
53 count += id3v1_set_string(s, "TIT2", buf + 3, 30); //title
54 count += id3v1_set_string(s, "TPE1", buf + 33, 30); //author|artist
55 count += id3v1_set_string(s, "TALB", buf + 63, 30); //album
56 count += id3v1_set_string(s, "TDRL", buf + 93, 4); //date
57 count += id3v1_set_string(s, "comment", buf + 97, 30);
58 if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track
60 buf[126] = atoi(tag->value);
63 buf[127] = 0xFF; /* default to unknown genre */
64 if ((tag = av_dict_get(s->metadata, "TCON", NULL, 0))) { //genre
65 for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
66 if (!av_strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
76 typedef struct MP3Context {
80 int64_t nb_frames_offset;
83 static int mp3_write_trailer(struct AVFormatContext *s)
85 uint8_t buf[ID3v1_TAG_SIZE];
86 MP3Context *mp3 = s->priv_data;
88 /* write the id3v1 tag */
89 if (mp3 && mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {
90 avio_write(s->pb, buf, ID3v1_TAG_SIZE);
93 /* write number of frames */
94 if (mp3 && mp3->nb_frames_offset) {
95 avio_seek(s->pb, mp3->nb_frames_offset, SEEK_SET);
96 avio_wb32(s->pb, s->streams[0]->nb_frames);
97 avio_seek(s->pb, 0, SEEK_END);
106 AVOutputFormat ff_mp2_muxer = {
108 .long_name = NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
109 .mime_type = "audio/x-mpeg",
110 .extensions = "mp2,m2a",
111 .audio_codec = CODEC_ID_MP2,
112 .video_codec = CODEC_ID_NONE,
113 .write_packet = ff_raw_write_packet,
114 .write_trailer = mp3_write_trailer,
120 static const AVOption options[] = {
121 { "id3v2_version", "Select ID3v2 version to write. Currently 3 and 4 are supported.",
122 offsetof(MP3Context, id3v2_version), AV_OPT_TYPE_INT, {.dbl = 4}, 3, 4, AV_OPT_FLAG_ENCODING_PARAM},
123 { "write_id3v1", "Enable ID3v1 writing. ID3v1 tags are written in UTF-8 which may not be supported by most software.",
124 offsetof(MP3Context, write_id3v1), AV_OPT_TYPE_INT, {.dbl = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
128 static const AVClass mp3_muxer_class = {
129 .class_name = "MP3 muxer",
130 .item_name = av_default_item_name,
132 .version = LIBAVUTIL_VERSION_INT,
135 /* insert a dummy frame containing number of frames */
136 static void mp3_write_xing(AVFormatContext *s)
138 AVCodecContext *codec = s->streams[0]->codec;
139 MP3Context *mp3 = s->priv_data;
140 int bitrate_idx = 1; // 32 kbps
141 int64_t xing_offset = (codec->channels == 2) ? 32 : 17;
143 MPADecodeHeader mpah;
144 int srate_idx, i, channels;
146 for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++)
147 if (avpriv_mpa_freq_tab[i] == codec->sample_rate) {
151 if (i == FF_ARRAY_ELEMS(avpriv_mpa_freq_tab)) {
152 av_log(s, AV_LOG_ERROR, "Unsupported sample rate.\n");
156 switch (codec->channels) {
157 case 1: channels = MPA_MONO; break;
158 case 2: channels = MPA_STEREO; break;
159 default: av_log(s, AV_LOG_ERROR, "Unsupported number of channels.\n"); return;
162 /* dummy MPEG audio header */
163 header = 0xff << 24; // sync
164 header |= (0x7 << 5 | 0x3 << 3 | 0x1 << 1 | 0x1) << 16; // sync/mpeg-1/layer 3/no crc*/
165 header |= (bitrate_idx << 4 | srate_idx << 2) << 8;
166 header |= channels << 6;
167 avio_wb32(s->pb, header);
169 avpriv_mpegaudio_decode_header(&mpah, header);
171 ffio_fill(s->pb, 0, xing_offset);
172 ffio_wfourcc(s->pb, "Xing");
173 avio_wb32(s->pb, 0x1); // only number of frames
174 mp3->nb_frames_offset = avio_tell(s->pb);
177 mpah.frame_size -= 4 + xing_offset + 4 + 4 + 4;
178 ffio_fill(s->pb, 0, mpah.frame_size);
182 * Write an ID3v2 header at beginning of stream
185 static int mp3_write_header(struct AVFormatContext *s)
187 MP3Context *mp3 = s->priv_data;
190 ret = ff_id3v2_write(s, mp3->id3v2_version, ID3v2_DEFAULT_MAGIC);
200 AVOutputFormat ff_mp3_muxer = {
202 .long_name = NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
203 .mime_type = "audio/x-mpeg",
205 .priv_data_size = sizeof(MP3Context),
206 .audio_codec = CODEC_ID_MP3,
207 .video_codec = CODEC_ID_NONE,
208 .write_header = mp3_write_header,
209 .write_packet = ff_raw_write_packet,
210 .write_trailer = mp3_write_trailer,
211 .flags = AVFMT_NOTIMESTAMPS,
212 .priv_class = &mp3_muxer_class,