ps.c

uclinux 下的vlc播放器源代码

/*****************************************************************************
 * ps.c: Program Stream demux module for VLC.
 *****************************************************************************
 * Copyright (C) 2004 the VideoLAN team
 * $Id: ps.c 17768 2006-11-14 20:21:24Z hartman $
 *
 * Authors: Laurent Aimar <[e-mail]>
 *
 * 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
 *****************************************************************************/
#include <stdlib.h>                                      /* malloc(), free() */

#include <vlc/vlc.h>
#include <vlc/input.h>

#include "ps.h"

/* TODO:
 *  - re-add pre-scanning.
 *  - ...
 */

#define TIME_TEXT N_("Trust MPEG timestamps")
#define TIME_LONGTEXT N_("Normally we use the timestamps of the MPEG files " \
    "to calculate position and duration. However sometimes this might not " \
    "be usable. Disable this option to calculate from the bitrate instead." )

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

vlc_module_begin();
    set_description( _("MPEG-PS demuxer") );
    set_category( CAT_INPUT );
    set_subcategory( SUBCAT_INPUT_DEMUX );
    set_capability( "demux2", 1 );
    set_callbacks( Open, Close );
    add_shortcut( "ps" );

    add_bool( "ps-trust-timestamps", VLC_TRUE, NULL, TIME_TEXT,
                 TIME_LONGTEXT, VLC_TRUE );

    add_submodule();
    set_description( _("MPEG-PS demuxer") );
    set_capability( "demux2", 9 );
    set_callbacks( OpenAlt, Close );
vlc_module_end();

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/

struct demux_sys_t
{
    ps_psm_t    psm;
    ps_track_t  tk[PS_TK_COUNT];

    int64_t     i_scr;
    int         i_mux_rate;
    int64_t     i_length;
    int         i_time_track;
    int64_t     i_current_pts;

    vlc_bool_t  b_lost_sync;
    vlc_bool_t  b_have_pack;
    vlc_bool_t  b_seekable;
};

static int Demux  ( demux_t *p_demux );
static int Control( demux_t *p_demux, int i_query, va_list args );

static int      ps_pkt_resynch( stream_t *, uint32_t *pi_code );
static block_t *ps_pkt_read   ( stream_t *, uint32_t i_code );

/*****************************************************************************
 * Open
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    demux_t     *p_demux = (demux_t*)p_this;
    demux_sys_t *p_sys;

    uint8_t     *p_peek;

    if( stream_Peek( p_demux->s, &p_peek, 4 ) < 4 )
    {
        msg_Err( p_demux, "cannot peek" );
        return VLC_EGENERIC;
    }

    if( p_peek[0] != 0 || p_peek[1] != 0 ||
        p_peek[2] != 1 || p_peek[3] < 0xb9 )
    {
        msg_Warn( p_demux, "this does not look like an MPEG PS stream, "
                  "continuing anyway" );
    }

    /* Fill p_demux field */
    p_demux->pf_demux = Demux;
    p_demux->pf_control = Control;
    p_demux->p_sys = p_sys = malloc( sizeof( demux_sys_t ) );

    /* Init p_sys */
    p_sys->i_mux_rate = 0;
    p_sys->i_scr      = -1;
    p_sys->i_length   = -1;
    p_sys->i_current_pts = (mtime_t) 0;
    p_sys->i_time_track = -1;
    
    p_sys->b_lost_sync = VLC_FALSE;
    p_sys->b_have_pack = VLC_FALSE;
    p_sys->b_seekable  = VLC_FALSE;

    stream_Control( p_demux->s, STREAM_CAN_SEEK, &p_sys->b_seekable );

    ps_psm_init( &p_sys->psm );
    ps_track_init( p_sys->tk );

    /* TODO prescanning of ES */

    return VLC_SUCCESS;
}

static int OpenAlt( vlc_object_t *p_this )
{
    demux_t *p_demux = (demux_t*)p_this;
    uint8_t *p_peek;

    if( stream_Peek( p_demux->s, &p_peek, 4 ) < 4 )
    {
        msg_Err( p_demux, "cannot peek" );
        return VLC_EGENERIC;
    }

    if( p_peek[0] != 0 || p_peek[1] != 0 ||
        p_peek[2] != 1 || p_peek[3] < 0xb9 )
    {
        if( !p_demux->b_force ) return VLC_EGENERIC;
    }

    return Open( p_this );
}

/*****************************************************************************
 * Close
 *****************************************************************************/
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;
    int i;

    for( i = 0; i < PS_TK_COUNT; i++ )
    {
        ps_track_t *tk = &p_sys->tk[i];
        if( tk->b_seen )
        {
            es_format_Clean( &tk->fmt );
            if( tk->es ) es_out_Del( p_demux->out, tk->es );
        }
    }

    ps_psm_destroy( &p_sys->psm );

    free( p_sys );
}

static int Demux2( demux_t *p_demux, vlc_bool_t b_end )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    int i_ret, i_id;
    uint32_t i_code;
    block_t *p_pkt;

    i_ret = ps_pkt_resynch( p_demux->s, &i_code );
    if( i_ret < 0 )
    {
        return 0;
    }
    else if( i_ret == 0 )
    {
        if( !p_sys->b_lost_sync )
            msg_Warn( p_demux, "garbage at input, trying to resync..." );

        p_sys->b_lost_sync = VLC_TRUE;
        return 1;
    }

    if( p_sys->b_lost_sync ) msg_Warn( p_demux, "found sync code" );
    p_sys->b_lost_sync = VLC_FALSE;

    if( ( p_pkt = ps_pkt_read( p_demux->s, i_code ) ) == NULL )
    {
        return 0;
    }
    if( (i_id = ps_pkt_id( p_pkt )) >= 0xc0 )
    {
        ps_track_t *tk = &p_sys->tk[PS_ID_TO_TK(i_id)];
        if( !ps_pkt_parse_pes( p_pkt, tk->i_skip ) )
        {
            if( b_end && p_pkt->i_pts > tk->i_last_pts )
            {
                tk->i_last_pts = p_pkt->i_pts;
            }
            else if ( tk->i_first_pts == -1 )
            {
                tk->i_first_pts = p_pkt->i_pts;
            }
        }
    }
    block_Release( p_pkt );
    return 1;
}

static void FindLength( demux_t *p_demux )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    int64_t i_current_pos = -1, i_size = 0, i_end = 0;
    int i;

    if( !var_CreateGetInteger( p_demux, "ps-trust-timestamps" ) )
        return;

    if( p_sys->i_length == -1 ) /* First time */
    {
        p_sys->i_length = 0;
        /* Check beginning */
        i = 0;
        i_current_pos = stream_Tell( p_demux->s );
        while( !p_demux->b_die && i < 40 && Demux2( p_demux, VLC_FALSE ) > 0 ) i++;

        /* Check end */
        i_size = stream_Size( p_demux->s );
        i_end = __MAX( 0, __MIN( 200000, i_size ) );
        stream_Seek( p_demux->s, i_size - i_end );
    
        while( !p_demux->b_die && Demux2( p_demux, VLC_TRUE ) > 0 );
        if( i_current_pos >= 0 ) stream_Seek( p_demux->s, i_current_pos );
    }

    for( i = 0; i < PS_TK_COUNT; i++ )
    {
        ps_track_t *tk = &p_sys->tk[i];
        if( tk->i_first_pts >= 0 && tk->i_last_pts > 0 )
            if( tk->i_last_pts > tk->i_first_pts )
            {
                int64_t i_length = (int64_t)tk->i_last_pts - tk->i_first_pts;
                if( i_length > p_sys->i_length )
                {
                    p_sys->i_length = i_length;
                    p_sys->i_time_track = i;
                    msg_Dbg( p_demux, "we found a length of: %lld", p_sys->i_length );
                }
            }
    }
}

/*****************************************************************************
 * Demux:
 *****************************************************************************/
static int Demux( demux_t *p_demux )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    int i_ret, i_id, i_mux_rate;
    uint32_t i_code;
    block_t *p_pkt;

    i_ret = ps_pkt_resynch( p_demux->s, &i_code );
    if( i_ret < 0 )
    {
        return 0;
    }
    else if( i_ret == 0 )
    {
        if( !p_sys->b_lost_sync )
            msg_Warn( p_demux, "garbage at input, trying to resync..." );