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ffmpeg / libavformat / mp3enc.c @ f59d8ff8

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/*
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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 FFmpeg.
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 *
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 * FFmpeg 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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 * FFmpeg 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 FFmpeg; 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 <strings.h>
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#include "avformat.h"
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#include "id3v1.h"
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#include "id3v2.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/opt.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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    AVMetadataTag *tag;
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    if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
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        strncpy(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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    AVMetadataTag *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_metadata_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_metadata_get(s->metadata, "TCON", NULL, 0))) { //genre
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        for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
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            if (!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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/* simple formats */
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static void id3v2_put_size(AVFormatContext *s, int size)
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{
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    avio_w8(s->pb, size >> 21 & 0x7f);
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    avio_w8(s->pb, size >> 14 & 0x7f);
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    avio_w8(s->pb, size >> 7  & 0x7f);
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    avio_w8(s->pb, size       & 0x7f);
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}
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static int string_is_ascii(const uint8_t *str)
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{
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    while (*str && *str < 128) str++;
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    return !*str;
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}
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/**
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 * Write a text frame with one (normal frames) or two (TXXX frames) strings
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 * according to encoding (only UTF-8 or UTF-16+BOM supported).
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 * @return number of bytes written or a negative error code.
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 */
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static int id3v2_put_ttag(AVFormatContext *s, const char *str1, const char *str2,
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                          uint32_t tag, enum ID3v2Encoding enc)
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{
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    int len;
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    uint8_t *pb;
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    int (*put)(AVIOContext*, const char*);
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    AVIOContext *dyn_buf;
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    if (url_open_dyn_buf(&dyn_buf) < 0)
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        return AVERROR(ENOMEM);
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    /* check if the strings are ASCII-only and use UTF16 only if
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     * they're not */
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    if (enc == ID3v2_ENCODING_UTF16BOM && string_is_ascii(str1) &&
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        (!str2 || string_is_ascii(str2)))
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        enc = ID3v2_ENCODING_ISO8859;
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    avio_w8(dyn_buf, enc);
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    if (enc == ID3v2_ENCODING_UTF16BOM) {
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        avio_wl16(dyn_buf, 0xFEFF);      /* BOM */
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        put = avio_put_str16le;
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    } else
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        put = avio_put_str;
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    put(dyn_buf, str1);
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    if (str2)
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        put(dyn_buf, str2);
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    len = url_close_dyn_buf(dyn_buf, &pb);
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    avio_wb32(s->pb, tag);
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    id3v2_put_size(s, len);
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    avio_wb16(s->pb, 0);
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    avio_write(s->pb, pb, len);
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    av_freep(&pb);
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    return len + ID3v2_HEADER_SIZE;
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}
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static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
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{
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    avio_write(s->pb, pkt->data, pkt->size);
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    put_flush_packet(s->pb);
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    return 0;
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}
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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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    /* write the id3v1 tag */
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    if (id3v1_create_tag(s, buf) > 0) {
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        avio_write(s->pb, buf, ID3v1_TAG_SIZE);
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        put_flush_packet(s->pb);
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    }
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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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    "mp2",
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    NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
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    "audio/x-mpeg",
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    "mp2,m2a",
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    0,
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    CODEC_ID_MP2,
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    CODEC_ID_NONE,
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    NULL,
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    mp3_write_packet,
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    mp3_write_trailer,
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};
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#endif
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#if CONFIG_MP3_MUXER
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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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} MP3Context;
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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), FF_OPT_TYPE_INT, 4, 3, 4, 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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    "MP3 muxer",
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    av_default_item_name,
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    options,
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    LIBAVUTIL_VERSION_INT,
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};
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static int id3v2_check_write_tag(AVFormatContext *s, AVMetadataTag *t, const char table[][4],
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                                 enum ID3v2Encoding enc)
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{
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    uint32_t tag;
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    int i;
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    if (t->key[0] != 'T' || strlen(t->key) != 4)
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        return -1;
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    tag = AV_RB32(t->key);
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    for (i = 0; *table[i]; i++)
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        if (tag == AV_RB32(table[i]))
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            return id3v2_put_ttag(s, t->value, NULL, tag, enc);
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    return -1;
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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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    AVMetadataTag *t = NULL;
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    int totlen = 0, enc = mp3->id3v2_version == 3 ? ID3v2_ENCODING_UTF16BOM :
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                                                    ID3v2_ENCODING_UTF8;
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    int64_t size_pos, cur_pos;
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    avio_wb32(s->pb, MKBETAG('I', 'D', '3', mp3->id3v2_version));
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    avio_w8(s->pb, 0);
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    avio_w8(s->pb, 0); /* flags */
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    /* reserve space for size */
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    size_pos = url_ftell(s->pb);
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    avio_wb32(s->pb, 0);
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    ff_metadata_conv(&s->metadata, ff_id3v2_34_metadata_conv, NULL);
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    if (mp3->id3v2_version == 4)
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        ff_metadata_conv(&s->metadata, ff_id3v2_4_metadata_conv, NULL);
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    while ((t = av_metadata_get(s->metadata, "", t, AV_METADATA_IGNORE_SUFFIX))) {
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        int ret;
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        if ((ret = id3v2_check_write_tag(s, t, ff_id3v2_tags, enc)) > 0) {
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            totlen += ret;
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            continue;
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        }
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        if ((ret = id3v2_check_write_tag(s, t, mp3->id3v2_version == 3 ?
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                                               ff_id3v2_3_tags : ff_id3v2_4_tags, enc)) > 0) {
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            totlen += ret;
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            continue;
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        }
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        /* unknown tag, write as TXXX frame */
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        if ((ret = id3v2_put_ttag(s, t->key, t->value, MKBETAG('T', 'X', 'X', 'X'), enc)) < 0)
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            return ret;
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        totlen += ret;
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    }
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    cur_pos = url_ftell(s->pb);
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    avio_seek(s->pb, size_pos, SEEK_SET);
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    id3v2_put_size(s, totlen);
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    avio_seek(s->pb, cur_pos, SEEK_SET);
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    return 0;
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}
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AVOutputFormat ff_mp3_muxer = {
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    "mp3",
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    NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
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    "audio/x-mpeg",
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    "mp3",
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    sizeof(MP3Context),
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    CODEC_ID_MP3,
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    CODEC_ID_NONE,
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    mp3_write_header,
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    mp3_write_packet,
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    mp3_write_trailer,
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    AVFMT_NOTIMESTAMPS,
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    .priv_class = &mp3_muxer_class,
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};
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#endif