FFmpeg/libavformat/oggdec.c

/*
 * Ogg bitstream support
 * Luca Barbato <lu_zero@gentoo.org>
 * Based on tcvp implementation
 *
 */

/**
    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 <stdio.h>
#include "oggdec.h"
#include "avformat.h"

#define MAX_PAGE_SIZE 65307
#define DECODER_BUFFER_SIZE MAX_PAGE_SIZE

static ogg_codec_t *ogg_codecs[] = {
    &vorbis_codec,
    &theora_codec,
    &flac_codec,
    &old_flac_codec,
    &ogm_video_codec,
    &ogm_audio_codec,
    &ogm_text_codec,
    &ogm_old_codec,
    NULL
};

//FIXME We could avoid some structure duplication
static int
ogg_save (AVFormatContext * s)
{
    ogg_t *ogg = s->priv_data;
    ogg_state_t *ost =
        av_malloc(sizeof (*ost) + (ogg->nstreams-1) * sizeof (*ogg->streams));
    int i;
    ost->pos = url_ftell (s->pb);
    ost->curidx = ogg->curidx;
    ost->next = ogg->state;
    ost->nstreams = ogg->nstreams;
    memcpy(ost->streams, ogg->streams, ogg->nstreams * sizeof(*ogg->streams));

    for (i = 0; i < ogg->nstreams; i++){
        ogg_stream_t *os = ogg->streams + i;
        os->buf = av_malloc (os->bufsize);
        memset (os->buf, 0, os->bufsize);
        memcpy (os->buf, ost->streams[i].buf, os->bufpos);
    }

    ogg->state = ost;

    return 0;
}

static int
ogg_restore (AVFormatContext * s, int discard)
{
    ogg_t *ogg = s->priv_data;
    ByteIOContext *bc = s->pb;
    ogg_state_t *ost = ogg->state;
    int i;

    if (!ost)
        return 0;

    ogg->state = ost->next;

    if (!discard){
        for (i = 0; i < ogg->nstreams; i++)
            av_free (ogg->streams[i].buf);

        url_fseek (bc, ost->pos, SEEK_SET);
        ogg->curidx = ost->curidx;
        ogg->nstreams = ost->nstreams;
        memcpy(ogg->streams, ost->streams,
               ost->nstreams * sizeof(*ogg->streams));
    }

    av_free (ost);

    return 0;
}

static int
ogg_reset (ogg_t * ogg)
{
    int i;

    for (i = 0; i < ogg->nstreams; i++){
        ogg_stream_t *os = ogg->streams + i;
        os->bufpos = 0;
        os->pstart = 0;
        os->psize = 0;
        os->granule = -1;
        os->lastgp = -1;
        os->nsegs = 0;
        os->segp = 0;
    }

    ogg->curidx = -1;

    return 0;
}

static ogg_codec_t *
ogg_find_codec (uint8_t * buf, int size)
{
    int i;

    for (i = 0; ogg_codecs[i]; i++)
        if (size >= ogg_codecs[i]->magicsize &&
            !memcmp (buf, ogg_codecs[i]->magic, ogg_codecs[i]->magicsize))
            return ogg_codecs[i];

    return NULL;
}

static int
ogg_find_stream (ogg_t * ogg, int serial)
{
    int i;

    for (i = 0; i < ogg->nstreams; i++)
        if (ogg->streams[i].serial == serial)
            return i;

    return -1;
}

static int
ogg_new_stream (AVFormatContext * s, uint32_t serial)
{

    ogg_t *ogg = s->priv_data;
    int idx = ogg->nstreams++;
    AVStream *st;
    ogg_stream_t *os;

    ogg->streams = av_realloc (ogg->streams,
                               ogg->nstreams * sizeof (*ogg->streams));
    memset (ogg->streams + idx, 0, sizeof (*ogg->streams));
    os = ogg->streams + idx;
    os->serial = serial;
    os->bufsize = DECODER_BUFFER_SIZE;
    os->buf = av_malloc(os->bufsize);
    os->header = -1;

    st = av_new_stream (s, idx);
    if (!st)
        return AVERROR(ENOMEM);

    av_set_pts_info(st, 64, 1, 1000000);

    return idx;
}

static int
ogg_new_buf(ogg_t *ogg, int idx)
{
    ogg_stream_t *os = ogg->streams + idx;
    uint8_t *nb = av_malloc(os->bufsize);
    int size = os->bufpos - os->pstart;
    if(os->buf){
        memcpy(nb, os->buf + os->pstart, size);
        av_free(os->buf);
    }
    os->buf = nb;
    os->bufpos = size;
    os->pstart = 0;

    return 0;
}

static int
ogg_read_page (AVFormatContext * s, int *str)
{
    ByteIOContext *bc = s->pb;
    ogg_t *ogg = s->priv_data;
    ogg_stream_t *os;
    int i = 0;
    int flags, nsegs;
    uint64_t gp;
    uint32_t serial;
    uint32_t seq;
    uint32_t crc;
    int size, idx;
    uint8_t sync[4];
    int sp = 0;

    if (get_buffer (bc, sync, 4) < 4)
        return -1;

    do{
        int c;

        if (sync[sp & 3] == 'O' &&
            sync[(sp + 1) & 3] == 'g' &&
            sync[(sp + 2) & 3] == 'g' && sync[(sp + 3) & 3] == 'S')
            break;

        c = url_fgetc (bc);
        if (c < 0)
            return -1;
        sync[sp++ & 3] = c;
    }while (i++ < MAX_PAGE_SIZE);

    if (i >= MAX_PAGE_SIZE){
        av_log (s, AV_LOG_INFO, "ogg, can't find sync word\n");
        return -1;
    }

    if (url_fgetc (bc) != 0)      /* version */
        return -1;

    flags = url_fgetc (bc);
    gp = get_le64 (bc);
    serial = get_le32 (bc);
    seq = get_le32 (bc);
    crc = get_le32 (bc);
    nsegs = url_fgetc (bc);

    idx = ogg_find_stream (ogg, serial);
    if (idx < 0){
        idx = ogg_new_stream (s, serial);
        if (idx < 0)
            return -1;
    }

    os = ogg->streams + idx;

    if(os->psize > 0)
        ogg_new_buf(ogg, idx);

    if (get_buffer (bc, os->segments, nsegs) < nsegs)
        return -1;

    os->nsegs = nsegs;
    os->segp = 0;

    size = 0;
    for (i = 0; i < nsegs; i++)
        size += os->segments[i];

    if (flags & OGG_FLAG_CONT){
        if (!os->psize){
            while (os->segp < os->nsegs){
                int seg = os->segments[os->segp++];
                os->pstart += seg;
                if (seg < 255)
                  break;
            }
        }
    }else{
      os->psize = 0;
    }

    if (os->bufsize - os->bufpos < size){
        uint8_t *nb = av_malloc (os->bufsize *= 2);
        memcpy (nb, os->buf, os->bufpos);
        av_free (os->buf);
        os->buf = nb;
    }

    if (get_buffer (bc, os->buf + os->bufpos, size) < size)
        return -1;

    os->lastgp = os->granule;
    os->bufpos += size;
    os->granule = gp;
    os->flags = flags;

    if (str)
        *str = idx;

    return 0;
}

static int
ogg_packet (AVFormatContext * s, int *str, int *dstart, int *dsize)
{
    ogg_t *ogg = s->priv_data;
    int idx;
    ogg_stream_t *os;
    int complete = 0;
    int segp = 0, psize = 0;

#if 0
    av_log (s, AV_LOG_DEBUG, "ogg_packet: curidx=%i\n", ogg->curidx);
#endif

    do{
        idx = ogg->curidx;

        while (idx < 0){
            if (ogg_read_page (s, &idx) < 0)
                return -1;
        }

        os = ogg->streams + idx;

#if 0
        av_log (s, AV_LOG_DEBUG,
                "ogg_packet: idx=%d pstart=%d psize=%d segp=%d nsegs=%d\n",
                idx, os->pstart, os->psize, os->segp, os->nsegs);
#endif

        if (!os->codec){
            if (os->header < 0){
                os->codec = ogg_find_codec (os->buf, os->bufpos);
                if (!os->codec){
                    os->header = 0;
                    return 0;
                }
            }else{
                return 0;
            }
        }

        segp = os->segp;
        psize = os->psize;

        while (os->segp < os->nsegs){
            int ss = os->segments[os->segp++];
            os->psize += ss;
            if (ss < 255){
                complete = 1;
                break;
            }
        }

        if (!complete && os->segp == os->nsegs){
            ogg->curidx = -1;
        }
    }while (!complete);

#if 0
    av_log (s, AV_LOG_DEBUG,
            "ogg_packet: idx %i, frame size %i, start %i\n",
            idx, os->psize, os->pstart);
#endif

    ogg->curidx = idx;

    if (os->header < 0){
        int hdr = os->codec->header (s, idx);
        if (!hdr){
          os->header = os->seq;
          os->segp = segp;
          os->psize = psize;
          ogg->headers = 1;
        }else{
          os->pstart += os->psize;
          os->psize = 0;
        }
    }

    if (os->header > -1 && os->seq > os->header){
        os->pflags = 0;
        if (os->codec && os->codec->packet)
            os->codec->packet (s, idx);
        if (str)
            *str = idx;
        if (dstart)
            *dstart = os->pstart;
        if (dsize)
            *dsize = os->psize;
        os->pstart += os->psize;
        os->psize = 0;
    }

    os->seq++;
    if (os->segp == os->nsegs)
        ogg->curidx = -1;

    return 0;
}

static int
ogg_get_headers (AVFormatContext * s)
{
    ogg_t *ogg = s->priv_data;

    do{
        if (ogg_packet (s, NULL, NULL, NULL) < 0)
            return -1;
    }while (!ogg->headers);

#if 0
    av_log (s, AV_LOG_DEBUG, "found headers\n");
#endif

    return 0;
}

static uint64_t
ogg_gptopts (AVFormatContext * s, int i, uint64_t gp)
{
    ogg_t *ogg = s->priv_data;
    ogg_stream_t *os = ogg->streams + i;
    uint64_t pts = AV_NOPTS_VALUE;

    if(os->codec->gptopts){
        pts = os->codec->gptopts(s, i, gp);
    } else {
        pts = gp;
    }

    return pts;
}


static int
ogg_get_length (AVFormatContext * s)
{
    ogg_t *ogg = s->priv_data;
    int idx = -1, i;
    offset_t size, end;

    if(url_is_streamed(s->pb))
        return 0;

// already set
    if (s->duration != AV_NOPTS_VALUE)
        return 0;

    size = url_fsize(s->pb);
    if(size < 0)
        return 0;
    end = size > MAX_PAGE_SIZE? size - MAX_PAGE_SIZE: size;

    ogg_save (s);
    url_fseek (s->pb, end, SEEK_SET);

    while (!ogg_read_page (s, &i)){
        if (ogg->streams[i].granule != -1 && ogg->streams[i].granule != 0 &&
            ogg->streams[i].codec)
            idx = i;
    }

    if (idx != -1){
        s->streams[idx]->duration =
            ogg_gptopts (s, idx, ogg->streams[idx].granule);
    }

    ogg->size = size;
    ogg_restore (s, 0);
    ogg_save (s);
    while (!ogg_read_page (s, &i)) {
        if (i == idx && ogg->streams[i].granule != -1 && ogg->streams[i].granule != 0)
            break;
    }
    if (i == idx) {
        s->streams[idx]->start_time = ogg_gptopts (s, idx, ogg->streams[idx].granule);
        s->streams[idx]->duration -= s->streams[idx]->start_time;
    }
    ogg_restore (s, 0);

    return 0;
}


static int
ogg_read_header (AVFormatContext * s, AVFormatParameters * ap)
{
    ogg_t *ogg = s->priv_data;
    ogg->curidx = -1;
    //linear headers seek from start
    if (ogg_get_headers (s) < 0){
      return -1;
    }

    //linear granulepos seek from end
    ogg_get_length (s);

    //fill the extradata in the per codec callbacks
    return 0;
}


static int
ogg_read_packet (AVFormatContext * s, AVPacket * pkt)
{
    ogg_t *ogg;
    ogg_stream_t *os;
    int idx = -1;
    int pstart, psize;

    //Get an ogg packet
    do{
        if (ogg_packet (s, &idx, &pstart, &psize) < 0)
            return AVERROR(EIO);
    }while (idx < 0 || !s->streams[idx]);

    ogg = s->priv_data;
    os = ogg->streams + idx;

    //Alloc a pkt
    if (av_new_packet (pkt, psize) < 0)
        return AVERROR(EIO);
    pkt->stream_index = idx;
    memcpy (pkt->data, os->buf + pstart, psize);
    if (os->lastgp != -1LL){
        pkt->pts = ogg_gptopts (s, idx, os->lastgp);
        os->lastgp = -1;
    }

    pkt->flags = os->pflags;

    return psize;
}


static int
ogg_read_close (AVFormatContext * s)
{
    ogg_t *ogg = s->priv_data;
    int i;

    for (i = 0; i < ogg->nstreams; i++){
        av_free (ogg->streams[i].buf);
        av_free (ogg->streams[i].private);
    }
    av_free (ogg->streams);
    return 0;
}


static int64_t
ogg_read_timestamp (AVFormatContext * s, int stream_index, int64_t * pos_arg,
                    int64_t pos_limit)
{
    ogg_t *ogg = s->priv_data;
    ByteIOContext *bc = s->pb;
    int64_t pts = AV_NOPTS_VALUE;
    int i;
    url_fseek(bc, *pos_arg, SEEK_SET);
    while (url_ftell(bc) < pos_limit && !ogg_read_page (s, &i)) {
        if (ogg->streams[i].granule != -1 && ogg->streams[i].granule != 0 &&
            ogg->streams[i].codec && i == stream_index) {
            pts = ogg_gptopts(s, i, ogg->streams[i].granule);
            // FIXME: this is the position of the packet after the one with above
            // pts.
            *pos_arg = url_ftell(bc);
            break;
        }
    }
    ogg_reset(ogg);
    return pts;
}

static int ogg_probe(AVProbeData *p)
{
    if (p->buf[0] == 'O' && p->buf[1] == 'g' &&
        p->buf[2] == 'g' && p->buf[3] == 'S' &&
        p->buf[4] == 0x0 && p->buf[5] <= 0x7 )
        return AVPROBE_SCORE_MAX;
    else
        return 0;
}

AVInputFormat ogg_demuxer = {
    "ogg",
    "Ogg",
    sizeof (ogg_t),
    ogg_probe,
    ogg_read_header,
    ogg_read_packet,
    ogg_read_close,
    NULL,
    ogg_read_timestamp,
    .extensions = "ogg",
};