voc.c

uclinux 下的vlc播放器源代码

/*****************************************************************************
 * voc.c : Creative Voice File (.VOC) demux module for vlc
 *****************************************************************************
 * Copyright (C) 2005 Rémi Denis-Courmont
 * $Id: voc.c 16434 2006-08-30 15:18:13Z hartman $
 *
 * Authors: Rémi Denis-Courmont <rem # videolan.org>
 *
 * 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 <vlc/aout.h>

#include <codecs.h>

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

vlc_module_begin();
    set_description( _("VOC demuxer") );
    set_category( CAT_INPUT );
    set_subcategory( SUBCAT_INPUT_DEMUX );
    set_capability( "demux2", 10 );
    set_callbacks( Open, Close );
vlc_module_end();

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

struct demux_sys_t
{
    es_format_t     fmt;
    es_out_id_t     *p_es;

    int64_t         i_block_start;
    int64_t         i_block_end;

    int64_t         i_loop_offset;
    unsigned        i_loop_count;
    unsigned        i_silence_countdown;

    date_t          pts;
};

static const char ct_header[] = "Creative Voice File\x1a";

/*****************************************************************************
 * Open: check file and initializes structures
 *****************************************************************************/
static int Open( vlc_object_t * p_this )
{
    demux_t     *p_demux = (demux_t*)p_this;
    demux_sys_t *p_sys;
    uint8_t     *p_buf;
    uint16_t    i_data_offset, i_version;

    if( stream_Peek( p_demux->s, &p_buf, 26 ) < 26 )
        return VLC_EGENERIC;

    if( memcmp( p_buf, ct_header, 20 ) )
        return VLC_EGENERIC;
    p_buf += 20;

    i_data_offset = GetWLE( p_buf );
    if ( i_data_offset < 26 /* not enough room for full VOC header */ )
        return VLC_EGENERIC;
    p_buf += 2;

    i_version = GetWLE( p_buf );
    if( ( i_version != 0x10A ) && ( i_version != 0x114 ) )
        return VLC_EGENERIC; /* unknown VOC version */
    p_buf += 2;

    if( GetWLE( p_buf ) != (uint16_t)(0x1234 + ~i_version) )
        return VLC_EGENERIC;

    /* We have a valid VOC header */
    msg_Dbg( p_demux, "CT Voice file v%d.%d", i_version >> 8,
             i_version & 0xff );

    /* skip VOC header */
    if( stream_Read( p_demux->s, NULL, i_data_offset ) < i_data_offset )
        return VLC_EGENERIC;

    p_demux->pf_demux   = Demux;
    p_demux->pf_control = Control;
    p_demux->p_sys      = p_sys = malloc( sizeof( demux_sys_t ) );
    if( p_sys == NULL )
        return VLC_ENOMEM;

    p_sys->i_silence_countdown = p_sys->i_block_start = p_sys->i_block_end =
    p_sys->i_loop_count = 0;
    p_sys->p_es = NULL;

    date_Init( &p_sys->pts, 1, 1 );
    date_Set( &p_sys->pts, 1 );

    es_format_Init( &p_sys->fmt, AUDIO_ES, 0 );

    return VLC_SUCCESS;
}


static int fmtcmp( es_format_t *ofmt, es_format_t *nfmt )
{
    return (ofmt->audio.i_bitspersample != nfmt->audio.i_bitspersample)
        || (ofmt->audio.i_rate != nfmt->audio.i_rate)
        || (ofmt->audio.i_channels != nfmt->audio.i_channels);
}


/*
 * Converts old-style VOC sample rates to commonly used ones
 * so as not to confuse sound card drivers.
 * (I assume 16k, 24k and 32k are never found in .VOC files)
 */
static unsigned int fix_voc_sr( unsigned int sr )
{
    switch( sr )
    {
        /*case 8000:
            return 8000;*/
        case 11111:
            return 11025;

        case 22222:
            return 22050;

        case 44444:
            return 44100;
    }
    return sr;
}

static int ReadBlockHeader( demux_t *p_demux )
{
    es_format_t     new_fmt;
    uint8_t buf[8];
    int32_t i_block_size;
    demux_sys_t *p_sys = p_demux->p_sys;

    if( stream_Read( p_demux->s, buf, 4 ) < 4 )
        return VLC_EGENERIC; /* EOF */

    i_block_size = GetDWLE( buf ) >> 8;
    msg_Dbg( p_demux, "new block: type: %u, size: %u",
             (unsigned)*buf, i_block_size );

    es_format_Init( &new_fmt, AUDIO_ES, 0 );

    switch( *buf )
    {
        case 0: /* not possible : caught with earlier stream_Read */
            goto corrupt;

        case 1:
            if( i_block_size < 2 )
                goto corrupt;
            i_block_size -= 2;

            if( stream_Read( p_demux->s, buf, 2 ) < 2 )
                goto corrupt;

            if( buf[1] )
            {
                msg_Err( p_demux, "unsupported compression" );
                return VLC_EGENERIC;
            }

            new_fmt.i_codec = VLC_FOURCC('u','8',' ',' ');
            new_fmt.audio.i_rate = fix_voc_sr( 1000000L / (256L - buf[0]) );
            new_fmt.audio.i_bytes_per_frame = 1;
            new_fmt.audio.i_frame_length = 1;
            new_fmt.audio.i_channels = 1;
            new_fmt.audio.i_blockalign = 1;
            new_fmt.audio.i_bitspersample = 8;
            new_fmt.i_bitrate = new_fmt.audio.i_rate * 8;
            break;

        case 2: /* data block with same format as the previous one */
            if( p_sys->p_es == NULL )
                goto corrupt; /* no previous block! */

            memcpy( &new_fmt, &p_sys->fmt, sizeof( new_fmt ) );
            break;

        case 3: /* silence block */
            if( ( i_block_size != 3 )
             || ( stream_Read( p_demux->s, buf, 3 ) < 3 ) )
                goto corrupt;

            i_block_size = 0;
            p_sys->i_silence_countdown = GetWLE( buf );

            new_fmt.i_codec = VLC_FOURCC('u','8',' ',' ');
            new_fmt.audio.i_rate = fix_voc_sr( 1000000L / (256L - buf[0]) );
            new_fmt.audio.i_bytes_per_frame = 1;
            new_fmt.audio.i_frame_length = 1;
            new_fmt.audio.i_channels = 1;
            new_fmt.audio.i_blockalign = 1;
            new_fmt.audio.i_bitspersample = 8;
            new_fmt.i_bitrate = new_fmt.audio.i_rate * 8;
            break;

        case 6: /* repeat block */
            if( ( i_block_size != 2 )
             || ( stream_Read( p_demux->s, buf, 2 ) < 2 ) )
                goto corrupt;

            i_block_size = 0;
            p_sys->i_loop_count = GetWLE( buf );
            p_sys->i_loop_offset = stream_Tell( p_demux->s );
            break;

        case 7: /* repeat end block */
            if( i_block_size != 0 )
                goto corrupt;

            if( p_sys->i_loop_count > 0 )
            {
                if( stream_Seek( p_demux->s, p_sys->i_loop_offset ) )
                    msg_Warn( p_demux, "cannot loop: seek failed" );