root/modules/demux/ogg.c

/*****************************************************************************
 * ogg.c : ogg stream demux module for vlc
 *****************************************************************************
 * Copyright (C) 2001-2007 the VideoLAN team
 * $Id$
 *
 * Authors: Gildas Bazin <gbazin@netcourrier.com>
 *          Andre Pang <Andre.Pang@csiro.au> (Annodex support)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_demux.h>
#include <vlc_meta.h>
#include <vlc_input.h>

#include <ogg/ogg.h>

#include <vlc_codecs.h>
#include <vlc_bits.h>

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );

vlc_module_begin();
    set_shortname ( "OGG" );
    set_description( N_("OGG demuxer" ) );
    set_category( CAT_INPUT );
    set_subcategory( SUBCAT_INPUT_DEMUX );
    set_capability( "demux", 50 );
    set_callbacks( Open, Close );
    add_shortcut( "ogg" );
vlc_module_end();


/*****************************************************************************
 * Definitions of structures and functions used by this plugins
 *****************************************************************************/
typedef struct logical_stream_s
{
    ogg_stream_state os;                        /* logical stream of packets */

    es_format_t      fmt;
    es_format_t      fmt_old;                  /* format of old ES is reused */
    es_out_id_t      *p_es;
    double           f_rate;

    int              i_serial_no;

    /* the header of some logical streams (eg vorbis) contain essential
     * data for the decoder. We back them up here in case we need to re-feed
     * them to the decoder. */
    int              b_force_backup;
    int              i_packets_backup;
    uint8_t          *p_headers;
    int              i_headers;

    /* program clock reference (in units of 90kHz) derived from the previous
     * granulepos */
    mtime_t          i_pcr;
    mtime_t          i_interpolated_pcr;
    mtime_t          i_previous_pcr;

    /* Misc */
    int b_reinit;
    int i_granule_shift;

    /* kate streams have the number of headers in the ID header */
    int i_kate_num_headers;

    /* for Annodex logical bitstreams */
    int secondary_header_packets;

} logical_stream_t;

struct demux_sys_t
{
    ogg_sync_state oy;        /* sync and verify incoming physical bitstream */

    int i_streams;                           /* number of logical bitstreams */
    logical_stream_t **pp_stream;  /* pointer to an array of logical streams */

    logical_stream_t *p_old_stream; /* pointer to a old logical stream to avoid recreating it */

    /* program clock reference (in units of 90kHz) derived from the pcr of
     * the sub-streams */
    mtime_t i_pcr;

    /* stream state */
    int     i_eos;

    /* bitrate */
    int     i_bitrate;
};

/* OggDS headers for the new header format (used in ogm files) */
typedef struct
{
    ogg_int32_t width;
    ogg_int32_t height;
} stream_header_video_t;

typedef struct
{
    ogg_int16_t channels;
    ogg_int16_t padding;
    ogg_int16_t blockalign;
    ogg_int32_t avgbytespersec;
} stream_header_audio_t;

typedef struct
{
    char        streamtype[8];
    char        subtype[4];

    ogg_int32_t size;                               /* size of the structure */

    ogg_int64_t time_unit;                              /* in reference time */
    ogg_int64_t samples_per_unit;
    ogg_int32_t default_len;                                /* in media time */

    ogg_int32_t buffersize;
    ogg_int16_t bits_per_sample;
    ogg_int16_t padding;

    union
    {
        /* Video specific */
        stream_header_video_t video;
        /* Audio specific */
        stream_header_audio_t audio;
    } sh;
} stream_header_t;

#define OGG_BLOCK_SIZE 4096

/* Some defines from OggDS */
#define PACKET_TYPE_HEADER   0x01
#define PACKET_TYPE_BITS     0x07
#define PACKET_LEN_BITS01    0xc0
#define PACKET_LEN_BITS2     0x02
#define PACKET_IS_SYNCPOINT  0x08

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  Demux  ( demux_t * );
static int  Control( demux_t *, int, va_list );

/* Bitstream manipulation */
static int  Ogg_ReadPage     ( demux_t *, ogg_page * );
static void Ogg_UpdatePCR    ( logical_stream_t *, ogg_packet * );
static void Ogg_DecodePacket ( demux_t *, logical_stream_t *, ogg_packet * );

static int Ogg_BeginningOfStream( demux_t *p_demux );
static int Ogg_FindLogicalStreams( demux_t *p_demux );
static void Ogg_EndOfStream( demux_t *p_demux );

/* */
static void Ogg_LogicalStreamDelete( demux_t *p_demux, logical_stream_t *p_stream );
static bool Ogg_LogicalStreamResetEsFormat( demux_t *p_demux, logical_stream_t *p_stream );

/* Logical bitstream headers */
static void Ogg_ReadTheoraHeader( logical_stream_t *, ogg_packet * );
static void Ogg_ReadVorbisHeader( logical_stream_t *, ogg_packet * );
static void Ogg_ReadSpeexHeader( logical_stream_t *, ogg_packet * );
static void Ogg_ReadKateHeader( logical_stream_t *, ogg_packet * );
static void Ogg_ReadFlacHeader( demux_t *, logical_stream_t *, ogg_packet * );
static void Ogg_ReadAnnodexHeader( vlc_object_t *, logical_stream_t *, ogg_packet * );
static void Ogg_ReadDiracHeader( logical_stream_t *, ogg_packet * );

/*****************************************************************************
 * Open: initializes ogg demux structures
 *****************************************************************************/
static int Open( vlc_object_t * p_this )
{
    demux_t *p_demux = (demux_t *)p_this;
    demux_sys_t    *p_sys;
    const uint8_t  *p_peek;


    /* Check if we are dealing with an ogg stream */
    if( stream_Peek( p_demux->s, &p_peek, 4 ) < 4 ) return VLC_EGENERIC;
    if( !p_demux->b_force && memcmp( p_peek, "OggS", 4 ) )
    {
        return VLC_EGENERIC;
    }

    /* Set exported functions */
    p_demux->pf_demux = Demux;
    p_demux->pf_control = Control;
    p_demux->p_sys = p_sys = malloc( sizeof( demux_sys_t ) );
    if( !p_sys )
        return VLC_ENOMEM;

    memset( p_sys, 0, sizeof( demux_sys_t ) );
    p_sys->i_bitrate = 0;
    p_sys->pp_stream = NULL;
    p_sys->p_old_stream = NULL;

    /* Begnning of stream, tell the demux to look for elementary streams. */
    p_sys->i_eos = 0;

    /* Initialize the Ogg physical bitstream parser */
    ogg_sync_init( &p_sys->oy );

    return VLC_SUCCESS;
}

/*****************************************************************************
 * Close: frees unused data
 *****************************************************************************/
static void Close( vlc_object_t *p_this )
{
    demux_t *p_demux = (demux_t *)p_this;
    demux_sys_t *p_sys = p_demux->p_sys  ;

    /* Cleanup the bitstream parser */
    ogg_sync_clear( &p_sys->oy );

    Ogg_EndOfStream( p_demux );

    if( p_sys->p_old_stream )
        Ogg_LogicalStreamDelete( p_demux, p_sys->p_old_stream );

    free( p_sys );
}

/*****************************************************************************
 * Demux: reads and demuxes data packets
 *****************************************************************************
 * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 *****************************************************************************/
static int Demux( demux_t * p_demux )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    ogg_page    oggpage;
    ogg_packet  oggpacket;
    int         i_stream;


    if( p_sys->i_eos == p_sys->i_streams )
    {
        if( p_sys->i_eos )
        {
            msg_Dbg( p_demux, "end of a group of logical streams" );
            /* We keep the ES to try reusing it in Ogg_BeginningOfStream
             * only 1 ES is supported (common case for ogg web radio) */
            if( p_sys->i_streams == 1 )
            {
                p_sys->p_old_stream = p_sys->pp_stream[0];
                TAB_CLEAN( p_sys->i_streams, p_sys->pp_stream );
            }
            Ogg_EndOfStream( p_demux );
        }

        p_sys->i_eos = 0;
        if( Ogg_BeginningOfStream( p_demux ) != VLC_SUCCESS )
            return 0;

        msg_Dbg( p_demux, "beginning of a group of logical streams" );
        es_out_Control( p_demux->out, ES_OUT_RESET_PCR );
    }

    /*
     * Demux an ogg page from the stream
     */
    if( Ogg_ReadPage( p_demux, &oggpage ) != VLC_SUCCESS )
    {
        return 0; /* EOF */
    }

    /* Test for End of Stream */
    if( ogg_page_eos( &oggpage ) ) p_sys->i_eos++;


    for( i_stream = 0; i_stream < p_sys->i_streams; i_stream++ )
    {
        logical_stream_t *p_stream = p_sys->pp_stream[i_stream];

        if( ogg_stream_pagein( &p_stream->os, &oggpage ) != 0 )
            continue;

        while( ogg_stream_packetout( &p_stream->os, &oggpacket ) > 0 )
        {
            /* Read info from any secondary header packets, if there are any */
            if( p_stream->secondary_header_packets > 0 )
            {
                if( p_stream->fmt.i_codec == VLC_FOURCC('t','h','e','o') &&
                        oggpacket.bytes >= 7 &&
                        ! memcmp( oggpacket.packet, "\x80theora", 7 ) )
                {
                    Ogg_ReadTheoraHeader( p_stream, &oggpacket );
                    p_stream->secondary_header_packets = 0;
                }
                else if( p_stream->fmt.i_codec == VLC_FOURCC('v','o','r','b') &&
                        oggpacket.bytes >= 7 &&
                        ! memcmp( oggpacket.packet, "\x01vorbis", 7 ) )
                {
                    Ogg_ReadVorbisHeader( p_stream, &oggpacket );
                    p_stream->secondary_header_packets = 0;
                }
                else if ( p_stream->fmt.i_codec == VLC_FOURCC('c','m','m','l') )
                {
                    p_stream->secondary_header_packets = 0;
                }
            }

            if( p_stream->b_reinit )
            {
                /* If synchro is re-initialized we need to drop all the packets
                 * until we find a new dated one. */
                Ogg_UpdatePCR( p_stream, &oggpacket );

                if( p_stream->i_pcr >= 0 )
                {
                    p_stream->b_reinit = 0;
                }
                else
                {
                    p_stream->i_interpolated_pcr = -1;
                    continue;
                }

                /* An Ogg/vorbis packet contains an end date granulepos */
                if( p_stream->fmt.i_codec == VLC_FOURCC( 'v','o','r','b' ) ||
                    p_stream->fmt.i_codec == VLC_FOURCC( 's','p','x',' ' ) ||
                    p_stream->fmt.i_codec == VLC_FOURCC( 'f','l','a','c' ) )
                {
                    if( ogg_stream_packetout( &p_stream->os, &oggpacket ) > 0 )
                    {
                        Ogg_DecodePacket( p_demux, p_stream, &oggpacket );
                    }
                    else
                    {
                        es_out_Control( p_demux->out, ES_OUT_SET_PCR,
                                        p_stream->i_pcr );
                    }
                    continue;
                }
            }

            Ogg_DecodePacket( p_demux, p_stream, &oggpacket );
        }
        break;
    }

    i_stream = 0; p_sys->i_pcr = -1;
    for( ; i_stream < p_sys->i_streams; i_stream++ )
    {
        logical_stream_t *p_stream = p_sys->pp_stream[i_stream];

        if( p_stream->fmt.i_cat == SPU_ES )
            continue;
        if( p_stream->i_interpolated_pcr < 0 )
            continue;

        if( p_sys->i_pcr < 0 || p_stream->i_interpolated_pcr < p_sys->i_pcr )
            p_sys->i_pcr = p_stream->i_interpolated_pcr;
    }

    if( p_sys->i_pcr >= 0 )
    {
        es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_sys->i_pcr );
    }

    return 1;
}

/*****************************************************************************
 * Control:
 *****************************************************************************/
static int Control( demux_t *p_demux, int i_query, va_list args )
{
    demux_sys_t *p_sys  = p_demux->p_sys;
    int64_t *pi64;
    bool *pb_bool;
    int i;

    switch( i_query )
    {
        case DEMUX_HAS_UNSUPPORTED_META:
            pb_bool = (bool*)va_arg( args, bool* );
            *pb_bool = true;
            return VLC_SUCCESS;

        case DEMUX_GET_TIME:
            pi64 = (int64_t*)va_arg( args, int64_t * );
            *pi64 = p_sys->i_pcr;
            return VLC_SUCCESS;

        case DEMUX_SET_TIME:
            return VLC_EGENERIC;

        case DEMUX_SET_POSITION:
            for( i = 0; i < p_sys->i_streams; i++ )
            {
                logical_stream_t *p_stream = p_sys->pp_stream[i];

                /* we'll trash all the data until we find the next pcr */
                p_stream->b_reinit = 1;
                p_stream->i_pcr = -1;
                p_stream->i_interpolated_pcr = -1;
                ogg_stream_reset( &p_stream->os );
            }
            ogg_sync_reset( &p_sys->oy );

        default:
            return demux_vaControlHelper( p_demux->s, 0, -1, p_sys->i_bitrate,
                                           1, i_query, args );
    }
}

/****************************************************************************
 * Ogg_ReadPage: Read a full Ogg page from the physical bitstream.
 ****************************************************************************
 * Returns VLC_SUCCESS if a page has been read. An error might happen if we
 * are at the end of stream.
 ****************************************************************************/
static int Ogg_ReadPage( demux_t *p_demux, ogg_page *p_oggpage )
{
    demux_sys_t *p_ogg = p_demux->p_sys  ;
    int i_read = 0;
    char *p_buffer;

    while( ogg_sync_pageout( &p_ogg->oy, p_oggpage ) != 1 )
    {
        p_buffer = ogg_sync_buffer( &p_ogg->oy, OGG_BLOCK_SIZE );

        i_read = stream_Read( p_demux->s, p_buffer, OGG_BLOCK_SIZE );
        if( i_read <= 0 )
            return VLC_EGENERIC;

        ogg_sync_wrote( &p_ogg->oy, i_read );
    }

    return VLC_SUCCESS;
}

/****************************************************************************
 * Ogg_UpdatePCR: update the PCR (90kHz program clock reference) for the
 *                current stream.
 ****************************************************************************/
static void Ogg_UpdatePCR( logical_stream_t *p_stream,
                           ogg_packet *p_oggpacket )
{
    /* Convert the granulepos into a pcr */
    if( p_oggpacket->granulepos >= 0 )
    {
        if( p_stream->fmt.i_codec == VLC_FOURCC( 't','h','e','o' ) ||
            p_stream->fmt.i_codec == VLC_FOURCC( 'k','a','t','e' ) )
        {
            ogg_int64_t iframe = p_oggpacket->granulepos >>
              p_stream->i_granule_shift;
            ogg_int64_t pframe = p_oggpacket->granulepos -
              ( iframe << p_stream->i_granule_shift );

            p_stream->i_pcr = ( iframe + pframe ) * INT64_C(1000000)
                              / p_stream->f_rate;
        }
        else if( p_stream->fmt.i_codec == VLC_FOURCC( 'd','r','a','c' ) )
        {
            ogg_int64_t i_dts = p_oggpacket->granulepos >> 31;
            /* NB, OggDirac granulepos values are in units of 2*picturerate */
            p_stream->i_pcr = (i_dts/2) * INT64_C(1000000) / p_stream->f_rate;
        }
        else
        {
            p_stream->i_pcr = p_oggpacket->granulepos * INT64_C(1000000)
                              / p_stream->f_rate;
        }

        p_stream->i_interpolated_pcr = p_stream->i_pcr;
    }
    else
    {
        p_stream->i_pcr = -1;

        /* no granulepos available, try to interpolate the pcr.
         * If we can't then don't touch the old value. */
        if( p_stream->fmt.i_cat == VIDEO_ES )
            /* 1 frame per packet */
            p_stream->i_interpolated_pcr += (INT64_C(1000000) / p_stream->f_rate);
        else if( p_stream->fmt.i_bitrate )
            p_stream->i_interpolated_pcr +=
                ( p_oggpacket->bytes * INT64_C(1000000) /
                  p_stream->fmt.i_bitrate / 8 );
    }
}

/****************************************************************************
 * Ogg_DecodePacket: Decode an Ogg packet.
 ****************************************************************************/
static void Ogg_DecodePacket( demux_t *p_demux,
                              logical_stream_t *p_stream,
                              ogg_packet *p_oggpacket )
{
    block_t *p_block;
    bool b_selected;
    int i_header_len = 0;
    mtime_t i_pts = -1, i_interpolated_pts;

    /* Sanity check */
    if( !p_oggpacket->bytes )
    {
        msg_Dbg( p_demux, "discarding 0 sized packet" );
        return;
    }

    if( p_oggpacket->bytes >= 7 &&
        ! memcmp ( p_oggpacket->packet, "Annodex", 7 ) )
    {
        /* it's an Annodex packet -- skip it (do nothing) */
        return;
    }
    else if( p_oggpacket->bytes >= 7 &&
        ! memcmp ( p_oggpacket->packet, "AnxData", 7 ) )
    {
        /* it's an AnxData packet -- skip it (do nothing) */
        return;
    }

    if( p_stream->fmt.i_codec == VLC_FOURCC( 's','u','b','t' ) &&
        p_oggpacket->packet[0] & PACKET_TYPE_BITS ) return;

    /* Check the ES is selected */
    es_out_Control( p_demux->out, ES_OUT_GET_ES_STATE,
                    p_stream->p_es, &b_selected );

    if( p_stream->b_force_backup )
    {
        uint8_t *p_sav;
        bool b_store_size = true;
        bool b_store_num_headers = false;

        p_stream->i_packets_backup++;
        switch( p_stream->fmt.i_codec )
        {
        case VLC_FOURCC( 'v','o','r','b' ):
        case VLC_FOURCC( 's','p','x',' ' ):
        case VLC_FOURCC( 't','h','e','o' ):
            if( p_stream->i_packets_backup == 3 ) p_stream->b_force_backup = 0;
            break;

        case VLC_FOURCC( 'f','l','a','c' ):
            if( !p_stream->fmt.audio.i_rate && p_stream->i_packets_backup == 2 )
            {
                Ogg_ReadFlacHeader( p_demux, p_stream, p_oggpacket );
                p_stream->b_force_backup = 0;
            }
            else if( p_stream->fmt.audio.i_rate )
            {
                p_stream->b_force_backup = 0;
                if( p_oggpacket->bytes >= 9 )
                {
                    p_oggpacket->packet += 9;
                    p_oggpacket->bytes -= 9;
                }
            }
            b_store_size = false;
            break;

        case VLC_FOURCC( 'k','a','t','e' ):
            if( p_stream->i_packets_backup == 1)
                b_store_num_headers = true;
            if( p_stream->i_packets_backup == p_stream->i_kate_num_headers ) p_stream->b_force_backup = 0;
            break;

        default:
            p_stream->b_force_backup = 0;
            break;
        }

        /* Backup the ogg packet (likely an header packet) */
        p_stream->p_headers =
            realloc( p_sav = p_stream->p_headers, p_stream->i_headers +
                     p_oggpacket->bytes + (b_store_size ? 2 : 0) + (b_store_num_headers ? 1 : 0) );
        if( p_stream->p_headers )
        {
            uint8_t *p_extra = p_stream->p_headers + p_stream->i_headers;

            if( b_store_num_headers )
            {
                /* Kate streams store the number of headers in the first header,
                   so we can't just test for 3 as Vorbis/Theora */
                *(p_extra++) = p_stream->i_kate_num_headers;
            }
            if( b_store_size )
            {
                *(p_extra++) = p_oggpacket->bytes >> 8;
                *(p_extra++) = p_oggpacket->bytes & 0xFF;
            }
            memcpy( p_extra, p_oggpacket->packet, p_oggpacket->bytes );
            p_stream->i_headers += p_oggpacket->bytes + (b_store_size ? 2 : 0) + (b_store_num_headers ? 1 : 0);

            if( !p_stream->b_force_backup )
            {
                /* Last header received, commit changes */
                free( p_stream->fmt.p_extra );

                p_stream->fmt.i_extra = p_stream->i_headers;
                p_stream->fmt.p_extra =
                    realloc( p_stream->fmt.p_extra, p_stream->i_headers );
                if( p_stream->fmt.p_extra )
                    memcpy( p_stream->fmt.p_extra, p_stream->p_headers,
                            p_stream->i_headers );
                else
                    p_stream->fmt.i_extra = 0;

                if( Ogg_LogicalStreamResetEsFormat( p_demux, p_stream ) )
                    es_out_Control( p_demux->out, ES_OUT_SET_FMT,
                                    p_stream->p_es, &p_stream->fmt );
            }
        }
        else
        {
                p_stream->p_headers = p_sav;
        }

        b_selected = false; /* Discard the header packet */
    }

    /* Convert the pcr into a pts */
    if( p_stream->fmt.i_codec == VLC_FOURCC( 'v','o','r','b' ) ||
        p_stream->fmt.i_codec == VLC_FOURCC( 's','p','x',' ' ) ||
        p_stream->fmt.i_codec == VLC_FOURCC( 'f','l','a','c' ) )
    {
        if( p_stream->i_pcr >= 0 )
        {
            /* This is for streams where the granulepos of the header packets
             * doesn't match these of the data packets (eg. ogg web radios). */
            if( p_stream->i_previous_pcr == 0 &&
                p_stream->i_pcr  > 3 * DEFAULT_PTS_DELAY )
            {
                es_out_Control( p_demux->out, ES_OUT_RESET_PCR );

                /* Call the pace control */
                es_out_Control( p_demux->out, ES_OUT_SET_PCR,
                                p_stream->i_pcr );
            }

            p_stream->i_previous_pcr = p_stream->i_pcr;

            /* The granulepos is the end date of the sample */
            i_pts =  p_stream->i_pcr;
        }
    }

    /* Convert the granulepos into the next pcr */
    i_interpolated_pts = p_stream->i_interpolated_pcr;
    Ogg_UpdatePCR( p_stream, p_oggpacket );

    if( p_stream->i_pcr >= 0 )
    {
        /* This is for streams where the granulepos of the header packets
         * doesn't match these of the data packets (eg. ogg web radios). */
        if( p_stream->i_previous_pcr == 0 &&
            p_stream->i_pcr  > 3 * DEFAULT_PTS_DELAY )
        {
            es_out_Control( p_demux->out, ES_OUT_RESET_PCR );

            /* Call the pace control */
            es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_stream->i_pcr );
        }
    }

    if( p_stream->fmt.i_codec != VLC_FOURCC( 'v','o','r','b' ) &&
        p_stream->fmt.i_codec != VLC_FOURCC( 's','p','x',' ' ) &&
        p_stream->fmt.i_codec != VLC_FOURCC( 'f','l','a','c' ) &&
        p_stream->i_pcr >= 0 )
    {
        p_stream->i_previous_pcr = p_stream->i_pcr;

        /* The granulepos is the start date of the sample */
        i_pts = p_stream->i_pcr;
    }

    if( !b_selected )
    {
        /* This stream isn't currently selected so we don't need to decode it,
         * but we did need to store its pcr as it might be selected later on */
        return;
    }

    if( p_oggpacket->bytes <= 0 )
        return;

    if( !( p_block = block_New( p_demux, p_oggpacket->bytes ) ) ) return;

    /* Normalize PTS */
    if( i_pts == 0 ) i_pts = 1;
    else if( i_pts == -1 && i_interpolated_pts == 0 ) i_pts = 1;
    else if( i_pts == -1 ) i_pts = 0;

    if( p_stream->fmt.i_cat == AUDIO_ES )
        p_block->i_dts = p_block->i_pts = i_pts;
    else if( p_stream->fmt.i_cat == SPU_ES )
    {
        p_block->i_dts = p_block->i_pts = i_pts;
        p_block->i_length = 0;
    }
    else if( p_stream->fmt.i_codec == VLC_FOURCC( 't','h','e','o' ) )
        p_block->i_dts = p_block->i_pts = i_pts;
    else if( p_stream->fmt.i_codec == VLC_FOURCC( 'd','r','a','c' ) )
    {
        ogg_int64_t dts = p_oggpacket->granulepos >> 31;
        ogg_int64_t delay = (p_oggpacket->granulepos >> 9) & 0x1fff;

        uint64_t u_pnum = dts + delay;

        p_block->i_dts = p_stream->i_pcr;
        p_block->i_pts = 0;
        /* NB, OggDirac granulepos values are in units of 2*picturerate */
        if( -1 != p_oggpacket->granulepos )
            p_block->i_pts = u_pnum * INT64_C(1000000) / p_stream->f_rate / 2;
    }
    else
    {
        p_block->i_dts = i_pts;
        p_block->i_pts = 0;
    }

    if( p_stream->fmt.i_codec != VLC_FOURCC( 'v','o','r','b' ) &&
        p_stream->fmt.i_codec != VLC_FOURCC( 's','p','x',' ' ) &&
        p_stream->fmt.i_codec != VLC_FOURCC( 'f','l','a','c' ) &&
        p_stream->fmt.i_codec != VLC_FOURCC( 't','a','r','k' ) &&
        p_stream->fmt.i_codec != VLC_FOURCC( 't','h','e','o' ) &&
        p_stream->fmt.i_codec != VLC_FOURCC( 'c','m','m','l' ) &&
        p_stream->fmt.i_codec != VLC_FOURCC( 'd','r','a','c' ) &&
        p_stream->fmt.i_codec != VLC_FOURCC( 'k','a','t','e' ) )
    {
        /* We remove the header from the packet */
        i_header_len = (*p_oggpacket->packet & PACKET_LEN_BITS01) >> 6;
        i_header_len |= (*p_oggpacket->packet & PACKET_LEN_BITS2) << 1;

        if( p_stream->fmt.i_codec == VLC_FOURCC( 's','u','b','t' ))
        {
            /* But with subtitles we need to retrieve the duration first */
            int i, lenbytes = 0;

            if( i_header_len > 0 && p_oggpacket->bytes >= i_header_len + 1 )
            {
                for( i = 0, lenbytes = 0; i < i_header_len; i++ )
                {
                    lenbytes = lenbytes << 8;
                    lenbytes += *(p_oggpacket->packet + i_header_len - i);
                }
            }
            if( p_oggpacket->bytes - 1 - i_header_len > 2 ||
                ( p_oggpacket->packet[i_header_len + 1] != ' ' &&
                  p_oggpacket->packet[i_header_len + 1] != 0 &&
                  p_oggpacket->packet[i_header_len + 1] != '\n' &&
                  p_oggpacket->packet[i_header_len + 1] != '\r' ) )
            {
                p_block->i_length = (mtime_t)lenbytes * 1000;
            }
        }

        i_header_len++;
        if( p_block->i_buffer >= (unsigned int)i_header_len )
            p_block->i_buffer -= i_header_len;
        else
            p_block->i_buffer = 0;
    }

    if( p_stream->fmt.i_codec == VLC_FOURCC( 't','a','r','k' ) )
    {
        /* FIXME: the biggest hack I've ever done */
        msg_Warn( p_demux, "tarkin pts: %"PRId64", granule: %"PRId64,
                  p_block->i_pts, p_block->i_dts );
        msleep(10000);
    }

    memcpy( p_block->p_buffer, p_oggpacket->packet + i_header_len,
            p_oggpacket->bytes - i_header_len );

    es_out_Send( p_demux->out, p_stream->p_es, p_block );
}

/****************************************************************************
 * Ogg_FindLogicalStreams: Find the logical streams embedded in the physical
 *                         stream and fill p_ogg.
 *****************************************************************************
 * The initial page of a logical stream is marked as a 'bos' page.
 * Furthermore, the Ogg specification mandates that grouped bitstreams begin
 * together and all of the initial pages must appear before any data pages.
 *
 * On success this function returns VLC_SUCCESS.
 ****************************************************************************/
static int Ogg_FindLogicalStreams( demux_t *p_demux )
{
    demux_sys_t *p_ogg = p_demux->p_sys  ;
    ogg_packet oggpacket;
    ogg_page oggpage;
    int i_stream;

    while( Ogg_ReadPage( p_demux, &oggpage ) == VLC_SUCCESS )
    {
        if( ogg_page_bos( &oggpage ) )
        {

            /* All is wonderful in our fine fine little world.
             * We found the beginning of our first logical stream. */
            while( ogg_page_bos( &oggpage ) )
            {
                logical_stream_t **pp_sav = p_ogg->pp_stream;
                logical_stream_t *p_stream;

                p_stream = malloc( sizeof(logical_stream_t) );
                if( !p_stream )
                    return VLC_ENOMEM;

                TAB_APPEND( p_ogg->i_streams, p_ogg->pp_stream, p_stream );

                memset( p_stream, 0, sizeof(logical_stream_t) );
                p_stream->p_headers = 0;
                p_stream->secondary_header_packets = 0;

                es_format_Init( &p_stream->fmt, 0, 0 );
                es_format_Init( &p_stream->fmt_old, 0, 0 );

                /* Setup the logical stream */
                p_stream->i_serial_no = ogg_page_serialno( &oggpage );
                ogg_stream_init( &p_stream->os, p_stream->i_serial_no );

                /* Extract the initial header from the first page and verify
                 * the codec type of tis Ogg bitstream */
                if( ogg_stream_pagein( &p_stream->os, &oggpage ) < 0 )
                {
                    /* error. stream version mismatch perhaps */
                    msg_Err( p_demux, "error reading first page of "
                             "Ogg bitstream data" );
                    return VLC_EGENERIC;
                }

                /* FIXME: check return value */
                ogg_stream_packetpeek( &p_stream->os, &oggpacket );

                /* Check for Vorbis header */