PeerStreamer

/*

 * MP3 muxer

 * Copyright (c) 2003 Fabrice Bellard

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include <strings.h>

#include "avformat.h"

#include "id3v1.h"

#include "id3v2.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/opt.h"

static int id3v1_set_string(AVFormatContext *s, const char *key,

                            uint8_t *buf, int buf_size)

{

    AVMetadataTag *tag;

    if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))

        strncpy(buf, tag->value, buf_size);

    return !!tag;

}

static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)

{

    AVMetadataTag *tag;

    int i, count = 0;

    memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */

    buf[0] = 'T';

    buf[1] = 'A';

    buf[2] = 'G';

    count += id3v1_set_string(s, "TIT2",    buf +  3, 30);       //title

    count += id3v1_set_string(s, "TPE1",    buf + 33, 30);       //author|artist

    count += id3v1_set_string(s, "TALB",    buf + 63, 30);       //album

    count += id3v1_set_string(s, "TDRL",    buf + 93,  4);       //date

    count += id3v1_set_string(s, "comment", buf + 97, 30);

    if ((tag = av_metadata_get(s->metadata, "TRCK", NULL, 0))) { //track

        buf[125] = 0;

        buf[126] = atoi(tag->value);

        count++;

    }

    buf[127] = 0xFF; /* default to unknown genre */

    if ((tag = av_metadata_get(s->metadata, "TCON", NULL, 0))) { //genre

        for(i = 0; i <= ID3v1_GENRE_MAX; i++) {

            if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {

                buf[127] = i;

                count++;

                break;

            }

        }

    }

    return count;

}

/* simple formats */

static void id3v2_put_size(AVFormatContext *s, int size)

{

    avio_w8(s->pb, size >> 21 & 0x7f);

    avio_w8(s->pb, size >> 14 & 0x7f);

    avio_w8(s->pb, size >> 7  & 0x7f);

    avio_w8(s->pb, size       & 0x7f);

}

static int string_is_ascii(const uint8_t *str)

{

    while (*str && *str < 128) str++;

    return !*str;

}

/**

 * Write a text frame with one (normal frames) or two (TXXX frames) strings

 * according to encoding (only UTF-8 or UTF-16+BOM supported).

 * @return number of bytes written or a negative error code.

 */

static int id3v2_put_ttag(AVFormatContext *s, const char *str1, const char *str2,

                          uint32_t tag, enum ID3v2Encoding enc)

{

    int len;

    uint8_t *pb;

    int (*put)(AVIOContext*, const char*);

    AVIOContext *dyn_buf;

    if (url_open_dyn_buf(&dyn_buf) < 0)

        return AVERROR(ENOMEM);

    /* check if the strings are ASCII-only and use UTF16 only if

     * they're not */

    if (enc == ID3v2_ENCODING_UTF16BOM && string_is_ascii(str1) &&

        (!str2 || string_is_ascii(str2)))

        enc = ID3v2_ENCODING_ISO8859;

    avio_w8(dyn_buf, enc);

    if (enc == ID3v2_ENCODING_UTF16BOM) {

        avio_wl16(dyn_buf, 0xFEFF);      /* BOM */

        put = avio_put_str16le;

    } else

        put = avio_put_str;

    put(dyn_buf, str1);

    if (str2)

        put(dyn_buf, str2);

    len = url_close_dyn_buf(dyn_buf, &pb);

    avio_wb32(s->pb, tag);

    id3v2_put_size(s, len);

    avio_wb16(s->pb, 0);

    avio_write(s->pb, pb, len);

    av_freep(&pb);

    return len + ID3v2_HEADER_SIZE;

}

static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)

{

    avio_write(s->pb, pkt->data, pkt->size);

    put_flush_packet(s->pb);

    return 0;

}

static int mp3_write_trailer(struct AVFormatContext *s)

{

    uint8_t buf[ID3v1_TAG_SIZE];

    /* write the id3v1 tag */

    if (id3v1_create_tag(s, buf) > 0) {

        avio_write(s->pb, buf, ID3v1_TAG_SIZE);

        put_flush_packet(s->pb);

    }

    return 0;

}

#if CONFIG_MP2_MUXER

AVOutputFormat ff_mp2_muxer = {

    "mp2",

    NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),

    "audio/x-mpeg",

    "mp2,m2a",

    0,

    CODEC_ID_MP2,

    CODEC_ID_NONE,

    NULL,

    mp3_write_packet,

    mp3_write_trailer,

};

#endif

#if CONFIG_MP3_MUXER

typedef struct MP3Context {

    const AVClass *class;

    int id3v2_version;

} MP3Context;

static const AVOption options[] = {

    { "id3v2_version", "Select ID3v2 version to write. Currently 3 and 4 are supported.",

      offsetof(MP3Context, id3v2_version), FF_OPT_TYPE_INT, 4, 3, 4, AV_OPT_FLAG_ENCODING_PARAM},

    { NULL },

};

static const AVClass mp3_muxer_class = {

    "MP3 muxer",

    av_default_item_name,

    options,

    LIBAVUTIL_VERSION_INT,

};

static int id3v2_check_write_tag(AVFormatContext *s, AVMetadataTag *t, const char table[][4],

                                 enum ID3v2Encoding enc)

{

    uint32_t tag;

    int i;

    if (t->key[0] != 'T' || strlen(t->key) != 4)

        return -1;

    tag = AV_RB32(t->key);

    for (i = 0; *table[i]; i++)

        if (tag == AV_RB32(table[i]))

            return id3v2_put_ttag(s, t->value, NULL, tag, enc);

    return -1;

}

/**

 * Write an ID3v2 header at beginning of stream

 */

static int mp3_write_header(struct AVFormatContext *s)

{

    MP3Context  *mp3 = s->priv_data;

    AVMetadataTag *t = NULL;

    int totlen = 0, enc = mp3->id3v2_version == 3 ? ID3v2_ENCODING_UTF16BOM :

                                                    ID3v2_ENCODING_UTF8;

    int64_t size_pos, cur_pos;

    avio_wb32(s->pb, MKBETAG('I', 'D', '3', mp3->id3v2_version));

    avio_w8(s->pb, 0);

    avio_w8(s->pb, 0); /* flags */

    /* reserve space for size */

    size_pos = avio_tell(s->pb);

    avio_wb32(s->pb, 0);

    ff_metadata_conv(&s->metadata, ff_id3v2_34_metadata_conv, NULL);

    if (mp3->id3v2_version == 4)

        ff_metadata_conv(&s->metadata, ff_id3v2_4_metadata_conv, NULL);

    while ((t = av_metadata_get(s->metadata, "", t, AV_METADATA_IGNORE_SUFFIX))) {

        int ret;

        if ((ret = id3v2_check_write_tag(s, t, ff_id3v2_tags, enc)) > 0) {

            totlen += ret;

            continue;

        }

        if ((ret = id3v2_check_write_tag(s, t, mp3->id3v2_version == 3 ?

                                               ff_id3v2_3_tags : ff_id3v2_4_tags, enc)) > 0) {

            totlen += ret;

            continue;

        }

        /* unknown tag, write as TXXX frame */

        if ((ret = id3v2_put_ttag(s, t->key, t->value, MKBETAG('T', 'X', 'X', 'X'), enc)) < 0)

            return ret;

        totlen += ret;

    }

    cur_pos = avio_tell(s->pb);

    avio_seek(s->pb, size_pos, SEEK_SET);

    id3v2_put_size(s, totlen);

    avio_seek(s->pb, cur_pos, SEEK_SET);

    return 0;

}

AVOutputFormat ff_mp3_muxer = {

    "mp3",

    NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),

    "audio/x-mpeg",

    "mp3",

    sizeof(MP3Context),

    CODEC_ID_MP3,

    CODEC_ID_NONE,

    mp3_write_header,

    mp3_write_packet,

    mp3_write_trailer,

    AVFMT_NOTIMESTAMPS,

    .priv_class = &mp3_muxer_class,

};

#endif