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ffmpeg / libavformat / oggparsevorbis.c @ 056f6179

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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 "avformat.h"
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#include "bitstream.h"
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#include "bswap.h"
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#include "ogg2.h"
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extern int
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vorbis_comment (AVFormatContext * as, char *buf, int size)
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{
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    char *p = buf;
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    int s, n, j;
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    if (size < 4)
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        return -1;
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    s = le2me_32 (unaligned32 (p));
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    p += 4;
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    size -= 4;
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    if (size < s + 4)
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        return -1;
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    p += s;
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    size -= s;
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    n = le2me_32 (unaligned32 (p));
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    p += 4;
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    size -= 4;
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    while (size >= 4){
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        char *t, *v;
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        int tl, vl;
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        s = le2me_32 (unaligned32 (p));
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        p += 4;
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        size -= 4;
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        if (size < s)
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            break;
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        t = p;
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        p += s;
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        size -= 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"))
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                strncpy (as->author, ct, FFMIN(sizeof (as->author), vl));
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            else if (!strcmp (tt, "TITLE"))
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                strncpy (as->title, ct, FFMIN(sizeof (as->title), vl));
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            else if (!strcmp (tt, "COPYRIGHT"))
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                strncpy (as->copyright, ct, FFMIN(sizeof (as->copyright), vl));
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            else if (!strcmp (tt, "DESCRIPTION"))
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                strncpy (as->comment, ct, FFMIN(sizeof (as->comment), vl));
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            else if (!strcmp (tt, "GENRE"))
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                strncpy (as->genre, ct, FFMIN(sizeof (as->genre), vl));
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            else if (!strcmp (tt, "TRACKNUMBER"))
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                as->track = atoi (ct);
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            //Too bored to add others for today
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        }
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    }
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    if (size > 0)
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        av_log (as, AV_LOG_INFO, "%i bytes of comment header remain\n", size);
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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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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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    int cds = st->codec.extradata_size + os->psize + 2;
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    uint8_t *cdp;
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    if (os->seq > 2)
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        return 0;
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    st->codec.extradata = av_realloc (st->codec.extradata, cds);
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    cdp = st->codec.extradata + st->codec.extradata_size;
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    *cdp++ = os->psize >> 8;
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    *cdp++ = os->psize & 0xff;
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    memcpy (cdp, os->buf + os->pstart, os->psize);
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    st->codec.extradata_size = cds;
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    if (os->buf[os->pstart] == 1) {
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        uint8_t *p = os->buf + os->pstart + 11; //skip up to the audio channels
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        st->codec.channels = *p++;
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        st->codec.sample_rate = le2me_32 (unaligned32 (p));
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        p += 8; //skip maximum and and nominal bitrate
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        st->codec.bit_rate = le2me_32 (unaligned32 (p)); //Minimum bitrate
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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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    } else if (os->buf[os->pstart] == 3) {
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        vorbis_comment (s, os->buf + os->pstart + 7, os->psize - 8);
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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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};