mirror of https://git.videolan.org/git/ffmpeg.git
215 lines
6.7 KiB
C
215 lines
6.7 KiB
C
/*
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* MP3 muxer
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* Copyright (c) 2003 Fabrice Bellard
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avformat.h"
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#include "avio_internal.h"
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#include "id3v1.h"
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#include "id3v2.h"
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#include "rawenc.h"
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#include "libavutil/avstring.h"
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#include "libavcodec/mpegaudio.h"
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#include "libavcodec/mpegaudiodata.h"
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#include "libavcodec/mpegaudiodecheader.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/opt.h"
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#include "libavutil/dict.h"
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static int id3v1_set_string(AVFormatContext *s, const char *key,
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uint8_t *buf, int buf_size)
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{
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AVDictionaryEntry *tag;
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if ((tag = av_dict_get(s->metadata, key, NULL, 0)))
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av_strlcpy(buf, tag->value, buf_size);
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return !!tag;
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}
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static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
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{
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AVDictionaryEntry *tag;
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int i, count = 0;
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memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
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buf[0] = 'T';
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buf[1] = 'A';
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buf[2] = 'G';
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count += id3v1_set_string(s, "TIT2", buf + 3, 30); //title
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count += id3v1_set_string(s, "TPE1", buf + 33, 30); //author|artist
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count += id3v1_set_string(s, "TALB", buf + 63, 30); //album
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count += id3v1_set_string(s, "TDRL", buf + 93, 4); //date
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count += id3v1_set_string(s, "comment", buf + 97, 30);
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if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track
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buf[125] = 0;
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buf[126] = atoi(tag->value);
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count++;
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}
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buf[127] = 0xFF; /* default to unknown genre */
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if ((tag = av_dict_get(s->metadata, "TCON", NULL, 0))) { //genre
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for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
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if (!av_strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
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buf[127] = i;
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count++;
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break;
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}
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}
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}
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return count;
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}
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typedef struct MP3Context {
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const AVClass *class;
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int id3v2_version;
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int write_id3v1;
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int64_t nb_frames_offset;
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} MP3Context;
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static int mp3_write_trailer(struct AVFormatContext *s)
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{
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uint8_t buf[ID3v1_TAG_SIZE];
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MP3Context *mp3 = s->priv_data;
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/* write the id3v1 tag */
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if (mp3 && mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {
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avio_write(s->pb, buf, ID3v1_TAG_SIZE);
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}
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/* write number of frames */
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if (mp3 && mp3->nb_frames_offset) {
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avio_seek(s->pb, mp3->nb_frames_offset, SEEK_SET);
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avio_wb32(s->pb, s->streams[0]->nb_frames);
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avio_seek(s->pb, 0, SEEK_END);
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}
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avio_flush(s->pb);
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return 0;
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}
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#if CONFIG_MP2_MUXER
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AVOutputFormat ff_mp2_muxer = {
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.name = "mp2",
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.long_name = NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
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.mime_type = "audio/x-mpeg",
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.extensions = "mp2,m2a",
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.audio_codec = CODEC_ID_MP2,
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.video_codec = CODEC_ID_NONE,
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.write_packet = ff_raw_write_packet,
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.write_trailer = mp3_write_trailer,
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};
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#endif
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#if CONFIG_MP3_MUXER
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static const AVOption options[] = {
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{ "id3v2_version", "Select ID3v2 version to write. Currently 3 and 4 are supported.",
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offsetof(MP3Context, id3v2_version), AV_OPT_TYPE_INT, {.dbl = 4}, 3, 4, AV_OPT_FLAG_ENCODING_PARAM},
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{ "write_id3v1", "Enable ID3v1 writing. ID3v1 tags are written in UTF-8 which may not be supported by most software.",
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offsetof(MP3Context, write_id3v1), AV_OPT_TYPE_INT, {.dbl = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
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{ NULL },
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};
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static const AVClass mp3_muxer_class = {
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.class_name = "MP3 muxer",
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.item_name = av_default_item_name,
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.option = options,
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.version = LIBAVUTIL_VERSION_INT,
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};
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/* insert a dummy frame containing number of frames */
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static void mp3_write_xing(AVFormatContext *s)
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{
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AVCodecContext *codec = s->streams[0]->codec;
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MP3Context *mp3 = s->priv_data;
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int bitrate_idx = 1; // 32 kbps
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int64_t xing_offset = (codec->channels == 2) ? 32 : 17;
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int32_t header;
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MPADecodeHeader mpah;
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int srate_idx, i, channels;
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for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++)
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if (avpriv_mpa_freq_tab[i] == codec->sample_rate) {
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srate_idx = i;
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break;
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}
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if (i == FF_ARRAY_ELEMS(avpriv_mpa_freq_tab)) {
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av_log(s, AV_LOG_ERROR, "Unsupported sample rate.\n");
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return;
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}
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switch (codec->channels) {
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case 1: channels = MPA_MONO; break;
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case 2: channels = MPA_STEREO; break;
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default: av_log(s, AV_LOG_ERROR, "Unsupported number of channels.\n"); return;
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}
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/* dummy MPEG audio header */
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header = 0xff << 24; // sync
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header |= (0x7 << 5 | 0x3 << 3 | 0x1 << 1 | 0x1) << 16; // sync/mpeg-1/layer 3/no crc*/
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header |= (bitrate_idx << 4 | srate_idx << 2) << 8;
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header |= channels << 6;
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avio_wb32(s->pb, header);
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avpriv_mpegaudio_decode_header(&mpah, header);
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ffio_fill(s->pb, 0, xing_offset);
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ffio_wfourcc(s->pb, "Xing");
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avio_wb32(s->pb, 0x1); // only number of frames
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mp3->nb_frames_offset = avio_tell(s->pb);
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avio_wb32(s->pb, 0);
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mpah.frame_size -= 4 + xing_offset + 4 + 4 + 4;
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ffio_fill(s->pb, 0, mpah.frame_size);
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}
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/**
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* Write an ID3v2 header at beginning of stream
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*/
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static int mp3_write_header(struct AVFormatContext *s)
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{
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MP3Context *mp3 = s->priv_data;
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int ret;
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ret = ff_id3v2_write(s, mp3->id3v2_version, ID3v2_DEFAULT_MAGIC);
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if (ret < 0)
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return ret;
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if (s->pb->seekable)
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mp3_write_xing(s);
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return 0;
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}
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AVOutputFormat ff_mp3_muxer = {
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.name = "mp3",
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.long_name = NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
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.mime_type = "audio/x-mpeg",
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.extensions = "mp3",
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.priv_data_size = sizeof(MP3Context),
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.audio_codec = CODEC_ID_MP3,
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.video_codec = CODEC_ID_NONE,
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.write_header = mp3_write_header,
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.write_packet = ff_raw_write_packet,
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.write_trailer = mp3_write_trailer,
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.flags = AVFMT_NOTIMESTAMPS,
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.priv_class = &mp3_muxer_class,
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};
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#endif
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