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pva.c：源码内容
							/*****************************************************************************
 * pva.c: PVA demuxer
 *****************************************************************************
 * Copyright (C) 2004 VideoLAN
 * $Id: pva.c 7232 2004-04-01 23:21:13Z fenrir $
 *
 * Authors: Laurent Aimar <fenrir@via.ecp.fr>
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/
/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <stdlib.h>                                      /* malloc(), free() */
#include <vlc/vlc.h>
#include <vlc/input.h>
/* TODO:
 *  - ...
 */
/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Open    ( vlc_object_t * );
static void Close  ( vlc_object_t * );
vlc_module_begin();
    set_description( _("PVA demuxer" ) );
    set_capability( "demux2", 10 );
    set_callbacks( Open, Close );
    add_shortcut( "pva" );
vlc_module_end();
/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
struct demux_sys_t
{
    es_out_id_t *p_video;
    es_out_id_t *p_audio;
    /* counter */
    int          i_vc;
    int          i_ac;
    /* audio/video block */
    block_t     *p_pes; /* audio */
    block_t     *p_es;  /* video */
    int64_t     b_pcr_audio;
};
static int  Demux   ( demux_t *p_demux );
static int  Control ( demux_t *p_demux, int i_query, va_list args );
static int  ReSynch ( demux_t * );
static void ParsePES( demux_t * );
/*****************************************************************************
 * Open
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    demux_t     *p_demux = (demux_t*)p_this;
    demux_sys_t *p_sys;
    es_format_t  fmt;
    uint8_t     *p_peek;
    if( stream_Peek( p_demux->s, &p_peek, 5 ) < 5 )
    {
        msg_Err( p_demux, "cannot peek" );
        return VLC_EGENERIC;
    }
    if( p_peek[0] != 'A' || p_peek[1] != 'V' || p_peek[4] != 0x55 )
    {
        /* In case we had forced this demuxer we try to resynch */
        if( strcasecmp( p_demux->psz_demux, "pva" ) || ReSynch( p_demux ) )
        {
            msg_Warn( p_demux, "PVA module discarded" );
            return VLC_EGENERIC;
        }
    }
    /* 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 ) );
    /* Register one audio and one video stream */
    es_format_Init( &fmt, AUDIO_ES, VLC_FOURCC( 'm', 'p', 'g', 'a' ) );
    p_sys->p_audio = es_out_Add( p_demux->out, &fmt );
    es_format_Init( &fmt, VIDEO_ES, VLC_FOURCC( 'm', 'p', 'g', 'v' ) );
    p_sys->p_video = es_out_Add( p_demux->out, &fmt );
    p_sys->i_vc    = -1;
    p_sys->i_ac    = -1;
    p_sys->p_pes   = NULL;
    p_sys->p_es    = NULL;
    p_sys->b_pcr_audio = VLC_FALSE;
    return VLC_SUCCESS;
}
/*****************************************************************************
 * 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;
    if( p_sys->p_es )  block_Release( p_sys->p_es );
    if( p_sys->p_pes ) block_Release( p_sys->p_pes );
    free( p_sys );
}
/*****************************************************************************
 * Demux:
 *****************************************************************************/
static int Demux( demux_t *p_demux )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    uint8_t     *p_peek;
    int         i_size;
    block_t     *p_frame;
    int64_t     i_pts;
    int         i_skip;
    if( stream_Peek( p_demux->s, &p_peek, 8 ) < 8 )
    {
        msg_Warn( p_demux, "eof ?" );
        return 0;
    }
    if( p_peek[0] != 'A' || p_peek[1] != 'V' || p_peek[4] != 0x55 )
    {
        msg_Warn( p_demux, "lost synchro" );
        if( ReSynch( p_demux ) )
        {
            return -1;
        }
        if( stream_Peek( p_demux->s, &p_peek, 8 ) < 8 )
        {
            msg_Warn( p_demux, "eof ?" );
            return 0;
        }
    }
    i_size = GetWBE( &p_peek[6] );
    switch( p_peek[2] )
    {
        case 0x01:  /* VideoStream */
            if( p_sys->i_vc < 0 )
            {
                msg_Dbg( p_demux, "first packet for video" );
            }
            else if( ((p_sys->i_vc + 1)&0xff) != p_peek[3] )
            {
                msg_Dbg( p_demux, "packet lost (video)" );
                if( p_sys->p_es )
                {
                    block_ChainRelease( p_sys->p_es );
                    p_sys->p_es = NULL;
                }
            }
            p_sys->i_vc = p_peek[3];
            /* read the PTS and potential extra bytes TODO: make it a bit more optimised */
            i_pts = -1;
            i_skip = 8;
            if( p_peek[5]&0x10 )
            {
                int i_pre = p_peek[5]&0x3;
                if( ( p_frame = stream_Block( p_demux->s, 8 + 4 + i_pre ) ) )
                {
                    i_pts = GetDWBE( &p_frame->p_buffer[8] );
                    if( p_frame->i_buffer > 12 )
                    {
                        p_frame->p_buffer += 12;
                        p_frame->i_buffer -= 12;
                        block_ChainAppend( &p_sys->p_es, p_frame );
                    }
                    else
                    {
                        block_Release( p_frame );
                    }
                }
                i_size -= 4 + i_pre;
                i_skip  = 0;
                /* Set PCR */
                if( ( p_frame = p_sys->p_es ) )
                {
                    if( p_frame->i_pts > 0 && !p_sys->b_pcr_audio )
                    {
                        es_out_Control( p_demux->out, ES_OUT_SET_PCR, (int64_t)p_frame->i_pts);
                    }
                    es_out_Send( p_demux->out, p_sys->p_video, p_frame );
                    p_sys->p_es = NULL;
                }
            }
            if( ( p_frame = stream_Block( p_demux->s, i_size + i_skip ) ) )
            {
                p_frame->p_buffer += i_skip;
                p_frame->i_buffer -= i_skip;
                if( i_pts > 0 ) p_frame->i_pts = i_pts * 100 / 9;
                block_ChainAppend( &p_sys->p_es, p_frame );
            }
            break;
        case 0x02:  /* MainAudioStream */
            if( p_sys->i_ac < 0 )
            {
                msg_Dbg( p_demux, "first packet for audio" );
            }
            else if( ((p_sys->i_ac + 1)&0xff) != p_peek[3] )
            {
                msg_Dbg( p_demux, "packet lost (audio)" );
                if( p_sys->p_pes )
                {
                    block_ChainRelease( p_sys->p_pes );
                    p_sys->p_pes = NULL;
                }
            }
            p_sys->i_ac = p_peek[3];
            if( p_peek[5]&0x10 && p_sys->p_pes )
            {
                ParsePES( p_demux );
            }
            if( ( p_frame = stream_Block( p_demux->s, i_size + 8 ) ) )
            {
                p_frame->p_buffer += 8;
                p_frame->i_buffer -= 8;
                /* XXX this a hack, some streams aren't compliant and
                 * doesn't set pes_start flag */
                if( p_sys->p_pes && p_frame->i_buffer > 4 &&
                    p_frame->p_buffer[0] == 0x00 &&
                    p_frame->p_buffer[1] == 0x00 &&
                    p_frame->p_buffer[2] == 0x01 )
                {
                    ParsePES( p_demux );
                }
                block_ChainAppend( &p_sys->p_pes, p_frame );
            }
            break;
        default:
            msg_Warn( p_demux, "unknown id=0x%x", p_peek[2] );
            stream_Read( p_demux->s, NULL, i_size + 8 );
            break;
    }
    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; */
    double f, *pf;
    int64_t i64;
    switch( i_query )
    {
        case DEMUX_GET_POSITION:
            if( ( i64 = stream_Size( p_demux->s ) ) > 0 )
            {
                pf = (double*) va_arg( args, double* );
                *pf = (double)stream_Tell( p_demux->s ) / (double)i64;
                return VLC_SUCCESS;
            }
            return VLC_EGENERIC;
        case DEMUX_SET_POSITION:
            f = (double) va_arg( args, double );
            i64 = stream_Size( p_demux->s );
            es_out_Control( p_demux->out, ES_OUT_RESET_PCR );
            if( stream_Seek( p_demux->s, (int64_t)(i64 * f) ) || ReSynch( p_demux ) )
            {
                return VLC_EGENERIC;
            }
            return VLC_SUCCESS;
#if 0
        case DEMUX_GET_TIME:
            pi64 = (int64_t*)va_arg( args, int64_t * );
            if( p_sys->i_time < 0 )
            {
                *pi64 = 0;
                return VLC_EGENERIC;
            }
            *pi64 = p_sys->i_time;
            return VLC_SUCCESS;
#if 0
        case DEMUX_GET_LENGTH:
            pi64 = (int64_t*)va_arg( args, int64_t * );
            if( p_sys->i_mux_rate > 0 )
            {
                *pi64 = (int64_t)1000000 * ( stream_Size( p_demux->s ) / 50 ) / p_sys->i_mux_rate;
                return VLC_SUCCESS;
            }
            *pi64 = 0;
            return VLC_EGENERIC;
#endif
        case DEMUX_GET_FPS:
            pf = (double*)va_arg( args, double * );
            *pf = (double)1000000.0 / (double)p_sys->i_pcr_inc;
            return VLC_SUCCESS;
#endif
        case DEMUX_SET_TIME:
        default:
            return VLC_EGENERIC;
    }
}
/*****************************************************************************
 * ReSynch:
 *****************************************************************************/
static int ReSynch( demux_t *p_demux )
{
    uint8_t *p_peek;
    int      i_skip;
    int      i_peek;
    while( !p_demux->b_die )
    {
        if( ( i_peek = stream_Peek( p_demux->s, &p_peek, 1024 ) ) < 8 )
        {
            return VLC_EGENERIC;
        }
        i_skip = 0;
        while( i_skip < i_peek - 5 )
        {
            if( p_peek[0] == 'A' && p_peek[1] == 'V' && p_peek[4] == 0x55 )
            {
                if( i_skip > 0 )
                {
                    stream_Read( p_demux->s, NULL, i_skip );
                }
                return VLC_SUCCESS;
            }
            p_peek++;
            i_skip++;
        }
        stream_Read( p_demux->s, NULL, i_skip );
    }
    return VLC_EGENERIC;
}
static void ParsePES( demux_t *p_demux )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    block_t     *p_pes = p_sys->p_pes;
    uint8_t     hdr[30];
    int         i_pes_size;
    int         i_skip;
    mtime_t     i_dts = -1;
    mtime_t     i_pts = -1;
    p_sys->p_pes = NULL;
    /* FIXME find real max size */
    block_ChainExtract( p_pes, hdr, 30 );
    if( hdr[0] != 0 || hdr[1] != 0 || hdr[2] != 1 )
    {
        msg_Warn( p_demux, "invalid hdr [0x%2.2x:%2.2x:%2.2x:%2.2x]",
                  hdr[0], hdr[1],hdr[2],hdr[3] );
        block_ChainRelease( p_pes );
        return;
    }
    i_pes_size = GetWBE( &hdr[4] );
    /* we assume mpeg2 PES */
    i_skip = hdr[8] + 9;
    if( hdr[7]&0x80 )    /* has pts */
    {
        i_pts = ((mtime_t)(hdr[ 9]&0x0e ) << 29)|
                 (mtime_t)(hdr[10] << 22)|
                ((mtime_t)(hdr[11]&0xfe) << 14)|
                 (mtime_t)(hdr[12] << 7)|
                 (mtime_t)(hdr[12] >> 1);
        if( hdr[7]&0x40 )    /* has dts */
        {
             i_dts = ((mtime_t)(hdr[14]&0x0e ) << 29)|
                     (mtime_t)(hdr[15] << 22)|
                    ((mtime_t)(hdr[16]&0xfe) << 14)|
                     (mtime_t)(hdr[17] << 7)|
                     (mtime_t)(hdr[18] >> 1);
        }
    }
    p_pes = block_ChainGather( p_pes );
    if( p_pes->i_buffer <= i_skip )
    {
        block_ChainRelease( p_pes );
        return;
    }
    p_pes->i_buffer -= i_skip;
    p_pes->p_buffer += i_skip;
    if( i_dts >= 0 ) p_pes->i_dts = i_dts * 100 / 9;
    if( i_pts >= 0 ) p_pes->i_pts = i_pts * 100 / 9;
    /* Set PCR */
    if( p_pes->i_pts > 0 )
    {
        es_out_Control( p_demux->out, ES_OUT_SET_PCR, (int64_t)p_pes->i_pts);
        p_sys->b_pcr_audio = VLC_TRUE;
    }
    es_out_Send( p_demux->out, p_sys->p_audio, p_pes );
}

						