PeerStreamer

/**

      Copyright (C) 2005  Michael Ahlberg, Måns Rullgård

      Permission is hereby granted, free of charge, to any person

      obtaining a copy of this software and associated documentation

      files (the "Software"), to deal in the Software without

      restriction, including without limitation the rights to use, copy,

      modify, merge, publish, distribute, sublicense, and/or sell copies

      of the Software, and to permit persons to whom the Software is

      furnished to do so, subject to the following conditions:

      The above copyright notice and this permission notice shall be

      included in all copies or substantial portions of the Software.

      THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

      EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

      MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

      NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

      HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

      WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

      OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

      DEALINGS IN THE SOFTWARE.

**/

#include <stdlib.h>

#include "libavutil/avstring.h"

#include "libavutil/bswap.h"

#include "libavcodec/get_bits.h"

#include "libavcodec/bytestream.h"

#include "avformat.h"

#include "oggdec.h"

/**

 * VorbisComment metadata conversion mapping.

 * from Ogg Vorbis I format specification: comment field and header specification

 * http://xiph.org/vorbis/doc/v-comment.html

 */

const AVMetadataConv ff_vorbiscomment_metadata_conv[] = {

    { "ALBUMARTIST", "album_artist"},

    { "TRACKNUMBER", "track"  },

    { 0 }

};

int

ff_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_set2(&as->metadata, tt, ct,

                                   AV_METADATA_DONT_STRDUP_KEY |

                                   AV_METADATA_DONT_STRDUP_VAL);

        }

    }

    if (p != end)

        av_log(as, AV_LOG_INFO, "%ti bytes of comment header remain\n", end-p);

    if (n > 0)

        av_log(as, AV_LOG_INFO,

               "truncated comment header, %i comments not found\n", n);

    return 0;

}

/** Parse the vorbis header

 * Vorbis Identification header from Vorbis_I_spec.html#vorbis-spec-codec

 * [vorbis_version] = read 32 bits as unsigned integer | Not used

 * [audio_channels] = read 8 bit integer as unsigned | Used

 * [audio_sample_rate] = read 32 bits as unsigned integer | Used

 * [bitrate_maximum] = read 32 bits as signed integer | Not used yet

 * [bitrate_nominal] = read 32 bits as signed integer | Not used yet

 * [bitrate_minimum] = read 32 bits as signed integer | Used as bitrate

 * [blocksize_0] = read 4 bits as unsigned integer | Not Used

 * [blocksize_1] = read 4 bits as unsigned integer | Not Used

 * [framing_flag] = read one bit | Not Used

 *    */

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];

        av_freep(&priv->packet[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;

    int pkt_type = os->buf[os->pstart];

    if (!(pkt_type & 1))

        return 0;

    if (!os->private) {

        os->private = av_mallocz(sizeof(struct oggvorbis_private));

        if (!os->private)

            return 0;

    }

    if (os->psize < 1 || pkt_type > 5)

        return -1;

    priv = os->private;

    priv->len[pkt_type >> 1] = os->psize;

    priv->packet[pkt_type >> 1] = av_mallocz(os->psize);

    memcpy(priv->packet[pkt_type >> 1], 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)

            ff_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 1;

}

const struct ogg_codec ff_vorbis_codec = {

    .magic = "\001vorbis",

    .magicsize = 7,

    .header = vorbis_header

};