3 * Copyright (c) 2003 Fabrice Bellard
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 #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 "libavcodec/mpegaudio.h"
34 #include "libavcodec/mpegaudiodata.h"
35 #include "libavcodec/mpegaudiodecheader.h"
36 #include "libavformat/avio_internal.h"
37 #include "libavutil/dict.h"
39 static int id3v1_set_string(AVFormatContext *s, const char *key,
40 uint8_t *buf, int buf_size)
42 AVDictionaryEntry *tag;
43 if ((tag = av_dict_get(s->metadata, key, NULL, 0)))
44 av_strlcpy(buf, tag->value, buf_size);
48 static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
50 AVDictionaryEntry *tag;
53 memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
57 /* we knowingly overspecify each tag length by one byte to compensate for the mandatory null byte added by av_strlcpy */
58 count += id3v1_set_string(s, "TIT2", buf + 3, 30 + 1); //title
59 count += id3v1_set_string(s, "TPE1", buf + 33, 30 + 1); //author|artist
60 count += id3v1_set_string(s, "TALB", buf + 63, 30 + 1); //album
61 count += id3v1_set_string(s, "TDRL", buf + 93, 4 + 1); //date
62 count += id3v1_set_string(s, "comment", buf + 97, 30 + 1);
63 if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track
65 buf[126] = atoi(tag->value);
68 buf[127] = 0xFF; /* default to unknown genre */
69 if ((tag = av_dict_get(s->metadata, "TCON", NULL, 0))) { //genre
70 for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
71 if (!av_strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
81 #define VBR_NUM_BAGS 400
82 #define VBR_TOC_SIZE 100
84 typedef struct MP3Context {
88 int64_t frames_offset;
94 uint64_t bag[VBR_NUM_BAGS];
97 static int mp2_write_trailer(struct AVFormatContext *s)
99 uint8_t buf[ID3v1_TAG_SIZE];
100 MP3Context *mp3 = s->priv_data;
102 /* write the id3v1 tag */
103 if (mp3 && mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {
104 avio_write(s->pb, buf, ID3v1_TAG_SIZE);
107 /* write number of frames */
108 if (mp3 && mp3->frames_offset) {
109 avio_seek(s->pb, mp3->frames_offset, SEEK_SET);
110 avio_wb32(s->pb, s->streams[0]->nb_frames);
111 avio_seek(s->pb, 0, SEEK_END);
120 AVOutputFormat ff_mp2_muxer = {
122 .long_name = NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
123 .mime_type = "audio/x-mpeg",
124 .extensions = "mp2,m2a",
125 .audio_codec = CODEC_ID_MP2,
126 .video_codec = CODEC_ID_NONE,
127 .write_packet = ff_raw_write_packet,
128 .write_trailer = mp2_write_trailer,
129 .flags = AVFMT_NOTIMESTAMPS,
135 static const AVOption options[] = {
136 { "id3v2_version", "Select ID3v2 version to write. Currently 3 and 4 are supported.",
137 offsetof(MP3Context, id3v2_version), AV_OPT_TYPE_INT, {.dbl = 4}, 3, 4, AV_OPT_FLAG_ENCODING_PARAM},
138 { "write_id3v1", "Enable ID3v1 writing. ID3v1 tags are written in UTF-8 which may not be supported by most software.",
139 offsetof(MP3Context, write_id3v1), AV_OPT_TYPE_INT, {.dbl = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
143 static const AVClass mp3_muxer_class = {
144 .class_name = "MP3 muxer",
145 .item_name = av_default_item_name,
147 .version = LIBAVUTIL_VERSION_INT,
150 static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
153 * Write an empty XING header and initialize respective data.
155 static int mp3_write_xing(AVFormatContext *s)
157 AVCodecContext *codec = s->streams[0]->codec;
158 MP3Context *mp3 = s->priv_data;
160 int best_bitrate_idx;
161 int best_bitrate_error= INT_MAX;
163 int32_t mask, header;
165 int srate_idx, i, channels;
168 for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++)
169 if (avpriv_mpa_freq_tab[i] == codec->sample_rate) {
173 if (i == FF_ARRAY_ELEMS(avpriv_mpa_freq_tab)) {
174 av_log(s, AV_LOG_ERROR, "Unsupported sample rate.\n");
178 switch (codec->channels) {
179 case 1: channels = MPA_MONO; break;
180 case 2: channels = MPA_STEREO; break;
181 default: av_log(s, AV_LOG_ERROR, "Unsupported number of channels.\n"); return -1;
184 /* dummy MPEG audio header */
185 header = 0xff << 24; // sync
186 header |= (0x7 << 5 | 0x3 << 3 | 0x1 << 1 | 0x1) << 16; // sync/mpeg-1/layer 3/no crc*/
187 header |= (srate_idx << 2) << 8;
188 header |= channels << 6;
190 for (bitrate_idx=1; bitrate_idx<15; bitrate_idx++) {
192 avpriv_mpegaudio_decode_header(&c, header | (bitrate_idx << (4+8)));
193 error= FFABS(c.bit_rate - codec->bit_rate);
194 if(error < best_bitrate_error){
195 best_bitrate_error= error;
196 best_bitrate_idx = bitrate_idx;
200 for (bitrate_idx= best_bitrate_idx;; bitrate_idx++) {
201 if (15 == bitrate_idx)
204 avpriv_mpegaudio_decode_header(&c, header | (bitrate_idx << (4+8)));
205 xing_offset=xing_offtbl[c.lsf == 1][c.nb_channels == 1];
209 + 4 // frames/size/toc flags
212 + VBR_TOC_SIZE; // toc
214 if (needed <= c.frame_size)
218 avio_wb32(s->pb, header);
219 ffio_fill(s->pb, 0, xing_offset);
220 avio_wb32(s->pb, MKBETAG('X', 'i', 'n', 'g'));
221 avio_wb32(s->pb, 0x01 | 0x02 | 0x04); // frames/size/toc
223 mp3->frames_offset = avio_tell(s->pb);
224 mp3->size = c.frame_size;
229 avio_wb32(s->pb, 0); // frames
230 avio_wb32(s->pb, 0); // size
233 for (i = 0; i < VBR_TOC_SIZE; ++i)
234 avio_w8(s->pb, (uint8_t)(255 * i / VBR_TOC_SIZE));
236 ffio_fill(s->pb, 0, c.frame_size - needed);
243 * Add a frame to XING data.
244 * Following lame's "VbrTag.c".
246 static void mp3_xing_add_frame(AVFormatContext *s, AVPacket *pkt)
248 MP3Context *mp3 = s->priv_data;
252 mp3->size += pkt->size;
254 if (mp3->want == ++mp3->seen) {
255 mp3->bag[mp3->pos] = mp3->size;
257 if (VBR_NUM_BAGS == ++mp3->pos) {
258 /* shrink table to half size by throwing away each second bag. */
259 for (i = 1; i < VBR_NUM_BAGS; i += 2)
260 mp3->bag[i >> 1] = mp3->bag[i];
262 /* double wanted amount per bag. */
264 /* adjust current position to half of table size. */
272 static void mp3_fix_xing(AVFormatContext *s)
274 MP3Context *mp3 = s->priv_data;
278 avio_seek(s->pb, mp3->frames_offset, SEEK_SET);
279 avio_wb32(s->pb, mp3->frames);
280 avio_wb32(s->pb, mp3->size);
282 avio_w8(s->pb, 0); // first toc entry has to be zero.
284 for (i = 1; i < VBR_TOC_SIZE; ++i) {
285 int j = i * mp3->pos / VBR_TOC_SIZE;
286 int seek_point = 256LL * mp3->bag[j] / mp3->size;
287 avio_w8(s->pb, FFMIN(seek_point, 255));
291 avio_seek(s->pb, 0, SEEK_END);
295 * Write an ID3v2 header at beginning of stream
298 static int mp3_write_header(struct AVFormatContext *s)
300 MP3Context *mp3 = s->priv_data;
303 ret = ff_id3v2_write(s, mp3->id3v2_version, ID3v2_DEFAULT_MAGIC);
313 static int mp3_write_packet(AVFormatContext *s, AVPacket *pkt)
315 if (! pkt || ! pkt->data || pkt->size < 4)
316 return ff_raw_write_packet(s, pkt);
318 MP3Context *mp3 = s->priv_data;
319 #ifdef FILTER_VBR_HEADERS
323 ff_mpegaudio_decode_header(&c, AV_RB32(pkt->data));
325 /* filter out XING and INFO headers. */
326 base = 4 + xing_offtbl[c.lsf == 1][c.nb_channels == 1];
328 if (base + 4 <= pkt->size) {
329 uint32_t v = AV_RB32(pkt->data + base);
331 if (MKBETAG('X','i','n','g') == v || MKBETAG('I','n','f','o') == v)
335 /* filter out VBRI headers. */
338 if (base + 4 <= pkt->size && MKBETAG('V','B','R','I') == AV_RB32(pkt->data + base))
342 if (mp3->frames_offset)
343 mp3_xing_add_frame(s, pkt);
345 return ff_raw_write_packet(s, pkt);
349 static int mp3_write_trailer(AVFormatContext *s)
351 MP3Context *mp3 = s->priv_data;
352 int ret=mp2_write_trailer(s);
357 if (mp3->frames_offset)
363 AVOutputFormat ff_mp3_muxer = {
365 .long_name = NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
366 .mime_type = "audio/x-mpeg",
368 .priv_data_size = sizeof(MP3Context),
369 .audio_codec = CODEC_ID_MP3,
370 .video_codec = CODEC_ID_NONE,
371 .write_header = mp3_write_header,
372 .write_packet = mp3_write_packet,
373 .write_trailer = mp3_write_trailer,
374 .flags = AVFMT_NOTIMESTAMPS,
375 .priv_class = &mp3_muxer_class,