libavformat/oggparsevorbis.c

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#include <stdlib.h>
#include "libavutil/avstring.h"
#include "libavutil/bswap.h"
#include "libavutil/dict.h"
#include "libavcodec/get_bits.h"
#include "libavcodec/bytestream.h"
#include "libavcodec/vorbis_parser.h"
#include "avformat.h"
#include "internal.h"
#include "oggdec.h"
#include "vorbiscomment.h"

static int ogm_chapter(AVFormatContext *as, uint8_t *key, uint8_t *val)
{
    int i, cnum, h, m, s, ms, keylen = strlen(key);
    AVChapter *chapter = NULL;

    if (keylen < 9 || sscanf(key, "CHAPTER%02d", &cnum) != 1)
        return 0;

    if (keylen == 9) {
        if (sscanf(val, "%02d:%02d:%02d.%03d", &h, &m, &s, &ms) < 4)
            return 0;

        avpriv_new_chapter(as, cnum, (AVRational){1,1000},
                       ms + 1000*(s + 60*(m + 60*h)),
                       AV_NOPTS_VALUE, NULL);
        av_free(val);
    } else if (!strcmp(key+9, "NAME")) {
        for(i = 0; i < as->nb_chapters; i++)
            if (as->chapters[i]->id == cnum) {
                chapter = as->chapters[i];
                break;
            }
        if (!chapter)
            return 0;

        av_dict_set(&chapter->metadata, "title", val,
                         AV_DICT_DONT_STRDUP_VAL);
    } else
        return 0;

    av_free(key);
    return 1;
}

int
ff_vorbis_comment(AVFormatContext * as, AVDictionary **m, const 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;

            if (!ogm_chapter(as, tt, ct))
                av_dict_set(m, tt, ct,
                                   AV_DICT_DONT_STRDUP_KEY |
                                   AV_DICT_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);

    ff_metadata_conv(m, NULL, ff_vorbiscomment_metadata_conv);

    return 0;
}


struct oggvorbis_private {
    unsigned int len[3];
    unsigned char *packet[3];
    VorbisParseContext vp;
    int64_t final_pts;
    int final_duration;
};


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 os->private ? 0 : -1;

    if (!os->private) {
        os->private = av_mallocz(sizeof(struct oggvorbis_private));
        if (!os->private)
            return -1;
    }

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

    priv = os->private;

    if (priv->packet[pkt_type>>1])
        return -1;
    if (pkt_type > 1 && !priv->packet[0] || pkt_type > 3 && !priv->packet[1])
        return -1;

    priv->len[pkt_type >> 1] = os->psize;
    priv->packet[pkt_type >> 1] = av_mallocz(os->psize);
    if (!priv->packet[pkt_type >> 1])
        return AVERROR(ENOMEM);
    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;
        int srate;

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

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

        st->codec->channels = bytestream_get_byte(&p);
        srate = 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 = AVMEDIA_TYPE_AUDIO;
        st->codec->codec_id = AV_CODEC_ID_VORBIS;

        if (srate > 0) {
            st->codec->sample_rate = srate;
            avpriv_set_pts_info(st, 64, 1, srate);
        }
    } else if (os->buf[os->pstart] == 3) {
        if (os->psize > 8 &&
            ff_vorbis_comment(s, &st->metadata, os->buf + os->pstart + 7, os->psize - 8) >= 0) {
            // drop all metadata we parsed and which is not required by libvorbis
            unsigned new_len = 7 + 4 + AV_RL32(priv->packet[1] + 7) + 4 + 1;
            if (new_len >= 16 && new_len < os->psize) {
                AV_WL32(priv->packet[1] + new_len - 5, 0);
                priv->packet[1][new_len - 1] = 1;
                priv->len[1] = new_len;
            }
        }
    } else {
        int ret;
        st->codec->extradata_size =
            fixup_vorbis_headers(s, priv, &st->codec->extradata);
        if ((ret = avpriv_vorbis_parse_extradata(st->codec, &priv->vp))) {
            av_freep(&st->codec->extradata);
            st->codec->extradata_size = 0;
            return ret;
        }
    }

    return 1;
}

static int vorbis_packet(AVFormatContext *s, int idx)
{
    struct ogg *ogg = s->priv_data;
    struct ogg_stream *os = ogg->streams + idx;
    struct oggvorbis_private *priv = os->private;
    int duration;

    /* first packet handling
       here we parse the duration of each packet in the first page and compare
       the total duration to the page granule to find the encoder delay and
       set the first timestamp */
    if ((!os->lastpts || os->lastpts == AV_NOPTS_VALUE) && !(os->flags & OGG_FLAG_EOS)) {
        int seg, d;
        uint8_t *last_pkt = os->buf + os->pstart;
        uint8_t *next_pkt = last_pkt;

        avpriv_vorbis_parse_reset(&priv->vp);
        duration = 0;
        seg = os->segp;
        d = avpriv_vorbis_parse_frame(&priv->vp, last_pkt, 1);
        if (d < 0) {
            os->pflags |= AV_PKT_FLAG_CORRUPT;
            return 0;
        }
        duration += d;
        last_pkt = next_pkt =  next_pkt + os->psize;
        for (; seg < os->nsegs; seg++) {
            if (os->segments[seg] < 255) {
                int d = avpriv_vorbis_parse_frame(&priv->vp, last_pkt, 1);
                if (d < 0) {
                    duration = os->granule;
                    break;
                }
                duration += d;
                last_pkt = next_pkt + os->segments[seg];
            }
            next_pkt += os->segments[seg];
        }
        os->lastpts = os->lastdts   = os->granule - duration;
        if(s->streams[idx]->start_time == AV_NOPTS_VALUE) {
            s->streams[idx]->start_time = FFMAX(os->lastpts, 0);
            if (s->streams[idx]->duration)
                s->streams[idx]->duration -= s->streams[idx]->start_time;
        }
        priv->final_pts             = AV_NOPTS_VALUE;
        avpriv_vorbis_parse_reset(&priv->vp);
    }

    /* parse packet duration */
    if (os->psize > 0) {
        duration = avpriv_vorbis_parse_frame(&priv->vp, os->buf + os->pstart, 1);
        if (duration < 0) {
            os->pflags |= AV_PKT_FLAG_CORRUPT;
            return 0;
        }
        os->pduration = duration;
    }

    /* final packet handling
       here we save the pts of the first packet in the final page, sum up all
       packet durations in the final page except for the last one, and compare
       to the page granule to find the duration of the final packet */
    if (os->flags & OGG_FLAG_EOS) {
        if (os->lastpts != AV_NOPTS_VALUE) {
            priv->final_pts = os->lastpts;
            priv->final_duration = 0;
        }
        if (os->segp == os->nsegs)
            os->pduration = os->granule - priv->final_pts - priv->final_duration;
        priv->final_duration += os->pduration;
    }

    return 0;
}

const struct ogg_codec ff_vorbis_codec = {
    .magic = "\001vorbis",
    .magicsize = 7,
    .header = vorbis_header,
    .packet = vorbis_packet,
    .nb_header = 3,
};

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