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ffmpeg / libavformat / oggparsevorbis.c @ 589790c2

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/**
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      Copyright (C) 2005  Michael Ahlberg, Måns Rullgård
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      Permission is hereby granted, free of charge, to any person
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      obtaining a copy of this software and associated documentation
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      files (the "Software"), to deal in the Software without
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      restriction, including without limitation the rights to use, copy,
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      modify, merge, publish, distribute, sublicense, and/or sell copies
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      of the Software, and to permit persons to whom the Software is
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      furnished to do so, subject to the following conditions:
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      The above copyright notice and this permission notice shall be
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      included in all copies or substantial portions of the Software.
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      THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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      EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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      MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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      NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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      HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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      WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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      OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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      DEALINGS IN THE SOFTWARE.
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**/
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#include <stdlib.h>
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#include "libavutil/avstring.h"
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#include "libavutil/bswap.h"
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#include "libavcodec/bitstream.h"
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#include "libavcodec/bytestream.h"
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#include "avformat.h"
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#include "oggdec.h"
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extern int
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vorbis_comment(AVFormatContext * as, uint8_t *buf, int size)
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{
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    const uint8_t *p = buf;
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    const uint8_t *end = buf + size;
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    unsigned s, n, j;
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    if (size < 8) /* must have vendor_length and user_comment_list_length */
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        return -1;
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    s = bytestream_get_le32(&p);
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    if (end - p < s)
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        return -1;
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    p += s;
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    n = bytestream_get_le32(&p);
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    while (p < end && n > 0) {
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        const char *t, *v;
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        int tl, vl;
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        s = bytestream_get_le32(&p);
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        if (end - p < s)
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            break;
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        t = p;
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        p += s;
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        n--;
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        v = memchr(t, '=', s);
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        if (!v)
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            continue;
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        tl = v - t;
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        vl = s - tl - 1;
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        v++;
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        if (tl && vl) {
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            char tt[tl + 1];
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            char ct[vl + 1];
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            for (j = 0; j < tl; j++)
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                tt[j] = toupper(t[j]);
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            tt[tl] = 0;
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            memcpy(ct, v, vl);
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            ct[vl] = 0;
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            // took from Vorbis_I_spec
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            if (!strcmp(tt, "AUTHOR") || !strcmp(tt, "ARTIST"))
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                av_strlcpy(as->author, ct, sizeof(as->author));
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            else if (!strcmp(tt, "TITLE"))
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                av_strlcpy(as->title, ct, sizeof(as->title));
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            else if (!strcmp(tt, "COPYRIGHT"))
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                av_strlcpy(as->copyright, ct, sizeof(as->copyright));
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            else if (!strcmp(tt, "DESCRIPTION"))
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                av_strlcpy(as->comment, ct, sizeof(as->comment));
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            else if (!strcmp(tt, "GENRE"))
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                av_strlcpy(as->genre, ct, sizeof(as->genre));
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            else if (!strcmp(tt, "TRACKNUMBER"))
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                as->track = atoi(ct);
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            else if (!strcmp(tt, "ALBUM"))
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                av_strlcpy(as->album, ct, sizeof(as->album));
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        }
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    }
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    if (p != end)
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        av_log(as, AV_LOG_INFO, "%ti bytes of comment header remain\n", p-end);
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    if (n > 0)
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        av_log(as, AV_LOG_INFO,
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               "truncated comment header, %i comments not found\n", n);
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    return 0;
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}
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/** Parse the vorbis header
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 * Vorbis Identification header from Vorbis_I_spec.html#vorbis-spec-codec
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 * [vorbis_version] = read 32 bits as unsigned integer | Not used
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 * [audio_channels] = read 8 bit integer as unsigned | Used
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 * [audio_sample_rate] = read 32 bits as unsigned integer | Used
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 * [bitrate_maximum] = read 32 bits as signed integer | Not used yet
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 * [bitrate_nominal] = read 32 bits as signed integer | Not used yet
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 * [bitrate_minimum] = read 32 bits as signed integer | Used as bitrate
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 * [blocksize_0] = read 4 bits as unsigned integer | Not Used
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 * [blocksize_1] = read 4 bits as unsigned integer | Not Used
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 * [framing_flag] = read one bit | Not Used
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 *    */
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typedef struct {
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    unsigned int len[3];
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    unsigned char *packet[3];
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} oggvorbis_private_t;
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static unsigned int
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fixup_vorbis_headers(AVFormatContext * as, oggvorbis_private_t *priv,
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                     uint8_t **buf)
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{
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    int i,offset, len;
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    unsigned char *ptr;
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    len = priv->len[0] + priv->len[1] + priv->len[2];
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    ptr = *buf = av_mallocz(len + len/255 + 64);
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    ptr[0] = 2;
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    offset = 1;
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    offset += av_xiphlacing(&ptr[offset], priv->len[0]);
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    offset += av_xiphlacing(&ptr[offset], priv->len[1]);
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    for (i = 0; i < 3; i++) {
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        memcpy(&ptr[offset], priv->packet[i], priv->len[i]);
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        offset += priv->len[i];
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    }
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    *buf = av_realloc(*buf, offset + FF_INPUT_BUFFER_PADDING_SIZE);
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    return offset;
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}
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static int
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vorbis_header (AVFormatContext * s, int idx)
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{
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    ogg_t *ogg = s->priv_data;
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    ogg_stream_t *os = ogg->streams + idx;
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    AVStream *st = s->streams[idx];
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    oggvorbis_private_t *priv;
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    if (os->seq > 2)
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        return 0;
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    if (os->seq == 0) {
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        os->private = av_mallocz(sizeof(oggvorbis_private_t));
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        if (!os->private)
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            return 0;
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    }
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    if (os->psize < 1)
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        return -1;
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    priv = os->private;
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    priv->len[os->seq] = os->psize;
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    priv->packet[os->seq] = av_mallocz(os->psize);
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    memcpy(priv->packet[os->seq], os->buf + os->pstart, os->psize);
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    if (os->buf[os->pstart] == 1) {
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        const uint8_t *p = os->buf + os->pstart + 7; /* skip "\001vorbis" tag */
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        unsigned blocksize, bs0, bs1;
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        if (os->psize != 30)
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            return -1;
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        if (bytestream_get_le32(&p) != 0) /* vorbis_version */
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            return -1;
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        st->codec->channels = bytestream_get_byte(&p);
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        st->codec->sample_rate = bytestream_get_le32(&p);
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        p += 4; // skip maximum bitrate
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        st->codec->bit_rate = bytestream_get_le32(&p); // nominal bitrate
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        p += 4; // skip minimum bitrate
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        blocksize = bytestream_get_byte(&p);
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        bs0 = blocksize & 15;
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        bs1 = blocksize >> 4;
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        if (bs0 > bs1)
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            return -1;
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        if (bs0 < 6 || bs1 > 13)
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            return -1;
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        if (bytestream_get_byte(&p) != 1) /* framing_flag */
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            return -1;
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        st->codec->codec_type = CODEC_TYPE_AUDIO;
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        st->codec->codec_id = CODEC_ID_VORBIS;
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        st->time_base.num = 1;
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        st->time_base.den = st->codec->sample_rate;
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    } else if (os->buf[os->pstart] == 3) {
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        if (os->psize > 8)
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            vorbis_comment (s, os->buf + os->pstart + 7, os->psize - 8);
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    } else {
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        st->codec->extradata_size =
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            fixup_vorbis_headers(s, priv, &st->codec->extradata);
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    }
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    return os->seq < 3;
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}
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ogg_codec_t vorbis_codec = {
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    .magic = "\001vorbis",
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    .magicsize = 7,
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    .header = vorbis_header
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};