midi

开发平台：
Unix_Linux

voc.c：源码内容
							/*****************************************************************************
 * voc.c : Creative Voice File (.VOC) demux module for vlc
 *****************************************************************************
 * Copyright (C) 2005 Rémi Denis-Courmont
 * $Id: 13d86d1b28feb78de8bae83fa220bb5d273703fe $
 *
 * 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
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_demux.h>
#include <vlc_aout.h>
#include <vlc_codecs.h>
/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );
vlc_module_begin ()
    set_description( N_("VOC demuxer") )
    set_category( CAT_INPUT )
    set_subcategory( SUBCAT_INPUT_DEMUX )
    set_capability( "demux", 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 Filex1a";
/*****************************************************************************
 * 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;
    const 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" );
                else
                    p_sys->i_loop_count--;
            }
            break;
        case 8:
            /*
             * Block 8 is a big kludge to add stereo support to block 1 :
             * A block of type 8 is always followed by a block of type 1
             * and specifies the number of channels in that 1-block
             * (normally block 1 are always mono). In practice, block type 9
             * is used for stereo rather than 8
             */
            if( ( i_block_size != 4 )
             || ( stream_Read( p_demux->s, buf, 4 ) < 4 ) )
                goto corrupt;
            if( buf[2] )
            {
                msg_Err( p_demux, "unsupported compression" );
                return VLC_EGENERIC;
            }
            new_fmt.i_codec = VLC_FOURCC('u','8',' ',' ');
            new_fmt.audio.i_channels = buf[3] + 1; /* can't be nul */
            new_fmt.audio.i_rate = 256000000L /
                          ((65536L - GetWLE(buf)) * new_fmt.audio.i_channels);
            new_fmt.audio.i_bytes_per_frame = new_fmt.audio.i_channels;
            new_fmt.audio.i_frame_length = 1;
            new_fmt.audio.i_blockalign = new_fmt.audio.i_bytes_per_frame;
            new_fmt.audio.i_bitspersample = 8 * new_fmt.audio.i_bytes_per_frame;
            new_fmt.i_bitrate = new_fmt.audio.i_rate * 8;
            /* read subsequent block 1 */
            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 );
            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;
            }
            break;
        case 9: /* newer data block with channel number and bits resolution */
            if( i_block_size < 12 )
                goto corrupt;
            i_block_size -= 12;
            if( ( stream_Read( p_demux->s, buf, 8 ) < 8 )
             || ( stream_Read( p_demux->s, NULL, 4 ) < 4 ) )
                goto corrupt;
            new_fmt.audio.i_rate = GetDWLE( buf );
            new_fmt.audio.i_bitspersample = buf[4];
            new_fmt.audio.i_channels = buf[5];
            switch( GetWLE( &buf[6] ) ) /* format */
            {
                case 0x0000: /* PCM */
                    switch( new_fmt.audio.i_bitspersample )
                    {
                        case 8:
                            new_fmt.i_codec = VLC_FOURCC('u','8',' ',' ');
                            break;
                        case 16:
                            new_fmt.i_codec = VLC_FOURCC('u','1','6','l');
                            break;
                        default:
                            msg_Err( p_demux, "unsupported bit res.: %u bits",
                                     new_fmt.audio.i_bitspersample );
                            return VLC_EGENERIC;
                    }
                    break;
                case 0x0004: /* signed */
                    switch( new_fmt.audio.i_bitspersample )
                    {
                        case 8:
                            new_fmt.i_codec = VLC_FOURCC('s','8',' ',' ');
                            break;
                        case 16:
                            new_fmt.i_codec = VLC_FOURCC('s','1','6','l');
                            break;
                        default:
                            msg_Err( p_demux, "unsupported bit res.: %u bits",
                                     new_fmt.audio.i_bitspersample );
                            return VLC_EGENERIC;
                    }
                    break;
                default:
                    msg_Err( p_demux, "unsupported compression" );
                    return VLC_EGENERIC;
            }
            new_fmt.audio.i_bytes_per_frame = new_fmt.audio.i_channels
                * (new_fmt.audio.i_bitspersample / 8);
            new_fmt.audio.i_frame_length = 1;
            new_fmt.audio.i_blockalign = new_fmt.audio.i_bytes_per_frame;
            new_fmt.i_bitrate = 8 * new_fmt.audio.i_rate
                                     * new_fmt.audio.i_bytes_per_frame;
            break;
        default:
            msg_Dbg( p_demux, "unknown block type %u - skipping block",
                     (unsigned)*buf);
        case 4: /* blocks of non-audio types can be skipped */
        case 5:
            if( stream_Read( p_demux->s, NULL, i_block_size ) < i_block_size )
                goto corrupt;
            i_block_size = 0;
            break;
    }
    p_sys->i_block_start = stream_Tell( p_demux->s );
    p_sys->i_block_end = p_sys->i_block_start + i_block_size;
    if( i_block_size || p_sys->i_silence_countdown )
    {
        /* we've read a block with data in it - update decoder */
        msg_Dbg( p_demux, "fourcc: %4.4s, channels: %d, "
                 "freq: %d Hz, bitrate: %dKo/s, blockalign: %d, "
                 "bits/samples: %d", (char *)&new_fmt.i_codec,
                 new_fmt.audio.i_channels, new_fmt.audio.i_rate,
                 new_fmt.i_bitrate / 8192, new_fmt.audio.i_blockalign,
                 new_fmt.audio.i_bitspersample );
        if( ( p_sys->p_es != NULL ) && fmtcmp( &p_sys->fmt, &new_fmt ) )
        {
            msg_Dbg( p_demux, "codec change needed" );
            es_out_Del( p_demux->out, p_sys->p_es );
            p_sys->p_es = NULL;
        }
        if( p_sys->p_es == NULL )
        {
            memcpy( &p_sys->fmt, &new_fmt, sizeof( p_sys->fmt ) );
            date_Change( &p_sys->pts, p_sys->fmt.audio.i_rate, 1 );
            p_sys->p_es = es_out_Add( p_demux->out, &p_sys->fmt );
        }
    }
    return VLC_SUCCESS;
corrupt:
    msg_Err( p_demux, "corrupted file - halting demux" );
    return VLC_EGENERIC;
}
/*****************************************************************************
 * Demux: read packet and send them to decoders
 *****************************************************************************
 * Returns -1 in case of error, 0 in case of EOF, 1 otherwise
 *****************************************************************************/
#define SAMPLES_BUFFER 1000
static int Demux( demux_t *p_demux )
{
    demux_sys_t *p_sys = p_demux->p_sys;
    block_t     *p_block;
    int64_t     i_offset, i;
    i_offset = stream_Tell( p_demux->s );
    while( ( i_offset >= p_sys->i_block_end )
         && ( p_sys->i_silence_countdown == 0 ) )
        if( ReadBlockHeader( p_demux ) != VLC_SUCCESS )
            return 0;
    if( p_sys->i_silence_countdown == 0 )
    {
        i = ( p_sys->i_block_end - i_offset )
            / p_sys->fmt.audio.i_bytes_per_frame;
        if( i > SAMPLES_BUFFER )
            i = SAMPLES_BUFFER;
        p_block = stream_Block( p_demux->s,
                                p_sys->fmt.audio.i_bytes_per_frame * i );
        if( p_block == NULL )
        {
            msg_Warn( p_demux, "cannot read data" );
            return 0;
        }
    }
    else
    {   /* emulates silence from the stream */
        i = p_sys->i_silence_countdown;
        if( i > SAMPLES_BUFFER )
            i = SAMPLES_BUFFER;
        p_block = block_New( p_demux, i );
        if( p_block == NULL )
            return VLC_ENOMEM;
        memset( p_block->p_buffer, 0, i );
        p_sys->i_silence_countdown -= i;
    }
    p_block->i_dts = p_block->i_pts =
        date_Increment( &p_sys->pts, p_sys->fmt.audio.i_frame_length * i );
    es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );
    es_out_Send( p_demux->out, p_sys->p_es, p_block );
    return 1;
}
/*****************************************************************************
 * Close: frees unused data
 *****************************************************************************/
static void Close ( vlc_object_t * p_this )
{
    demux_sys_t *p_sys  = ((demux_t *)p_this)->p_sys;
    free( p_sys );
}
/*****************************************************************************
 * Control:
 *****************************************************************************/
static int Control( demux_t *p_demux, int i_query, va_list args )
{
    demux_sys_t *p_sys  = p_demux->p_sys;
    return demux_vaControlHelper( p_demux->s, p_sys->i_block_start,
                                   p_sys->i_block_end,
                                   p_sys->fmt.i_bitrate,
                                   p_sys->fmt.audio.i_blockalign,
                                   i_query, args );
}

						