libavformat/oggparsevorbis.c

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#include <stdlib.h>
#include "libavutil/avstring.h"
#include "libavutil/bswap.h"
#include "libavcodec/bitstream.h"
#include "libavcodec/bytestream.h"
#include "avformat.h"
#include "oggdec.h"

int
vorbis_comment(AVFormatContext * as, uint8_t *buf, int size)
{
    const uint8_t *p = buf;
    const uint8_t *end = buf + size;
    unsigned n, j;
    int s;

    if (size < 8) /* must have vendor_length and user_comment_list_length */
        return -1;

    s = bytestream_get_le32(&p);

    if (end - p - 4 < s || s < 0)
        return -1;

    p += s;

    n = bytestream_get_le32(&p);

    while (end - p >= 4 && n > 0) {
        const char *t, *v;
        int tl, vl;

        s = bytestream_get_le32(&p);

        if (end - p < s || s < 0)
            break;

        t = p;
        p += s;
        n--;

        v = memchr(t, '=', s);
        if (!v)
            continue;

        tl = v - t;
        vl = s - tl - 1;
        v++;

        if (tl && vl) {
            char *tt, *ct;

            tt = av_malloc(tl + 1);
            ct = av_malloc(vl + 1);
            if (!tt || !ct) {
                av_freep(&tt);
                av_freep(&ct);
                av_log(as, AV_LOG_WARNING, "out-of-memory error. skipping VorbisComment tag.\n");
                continue;
            }

            for (j = 0; j < tl; j++)
                tt[j] = toupper(t[j]);
            tt[tl] = 0;

            memcpy(ct, v, vl);
            ct[vl] = 0;

            av_metadata_set(&as->metadata, tt, ct);

            av_freep(&tt);
            av_freep(&ct);
        }
    }

    if (p != end)
        av_log(as, AV_LOG_INFO, "%ti bytes of comment header remain\n", p-end);
    if (n > 0)
        av_log(as, AV_LOG_INFO,
               "truncated comment header, %i comments not found\n", n);

    return 0;
}


struct oggvorbis_private {
    unsigned int len[3];
    unsigned char *packet[3];
};


static unsigned int
fixup_vorbis_headers(AVFormatContext * as, struct oggvorbis_private *priv,
                     uint8_t **buf)
{
    int i,offset, len;
    unsigned char *ptr;

    len = priv->len[0] + priv->len[1] + priv->len[2];
    ptr = *buf = av_mallocz(len + len/255 + 64);

    ptr[0] = 2;
    offset = 1;
    offset += av_xiphlacing(&ptr[offset], priv->len[0]);
    offset += av_xiphlacing(&ptr[offset], priv->len[1]);
    for (i = 0; i < 3; i++) {
        memcpy(&ptr[offset], priv->packet[i], priv->len[i]);
        offset += priv->len[i];
    }
    *buf = av_realloc(*buf, offset + FF_INPUT_BUFFER_PADDING_SIZE);
    return offset;
}


static int
vorbis_header (AVFormatContext * s, int idx)
{
    struct ogg *ogg = s->priv_data;
    struct ogg_stream *os = ogg->streams + idx;
    AVStream *st = s->streams[idx];
    struct oggvorbis_private *priv;

    if (os->seq > 2)
        return 0;

    if (os->seq == 0) {
        os->private = av_mallocz(sizeof(struct oggvorbis_private));
        if (!os->private)
            return 0;
    }

    if (os->psize < 1)
        return -1;

    priv = os->private;
    priv->len[os->seq] = os->psize;
    priv->packet[os->seq] = av_mallocz(os->psize);
    memcpy(priv->packet[os->seq], os->buf + os->pstart, os->psize);
    if (os->buf[os->pstart] == 1) {
        const uint8_t *p = os->buf + os->pstart + 7; /* skip "\001vorbis" tag */
        unsigned blocksize, bs0, bs1;

        if (os->psize != 30)
            return -1;

        if (bytestream_get_le32(&p) != 0) /* vorbis_version */
            return -1;

        st->codec->channels = bytestream_get_byte(&p);
        st->codec->sample_rate = bytestream_get_le32(&p);
        p += 4; // skip maximum bitrate
        st->codec->bit_rate = bytestream_get_le32(&p); // nominal bitrate
        p += 4; // skip minimum bitrate

        blocksize = bytestream_get_byte(&p);
        bs0 = blocksize & 15;
        bs1 = blocksize >> 4;

        if (bs0 > bs1)
            return -1;
        if (bs0 < 6 || bs1 > 13)
            return -1;

        if (bytestream_get_byte(&p) != 1) /* framing_flag */
            return -1;

        st->codec->codec_type = CODEC_TYPE_AUDIO;
        st->codec->codec_id = CODEC_ID_VORBIS;

        st->time_base.num = 1;
        st->time_base.den = st->codec->sample_rate;
    } else if (os->buf[os->pstart] == 3) {
        if (os->psize > 8)
            vorbis_comment (s, os->buf + os->pstart + 7, os->psize - 8);
    } else {
        st->codec->extradata_size =
            fixup_vorbis_headers(s, priv, &st->codec->extradata);
    }

    return os->seq < 3;
}

const struct ogg_codec ff_vorbis_codec = {
    .magic = "\001vorbis",
    .magicsize = 7,
    .header = vorbis_header
};

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