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wav.c：源码内容
							/*****************************************************************************
 * wav.c: wav muxer module for vlc
 *****************************************************************************
 * Copyright (C) 2004 VideoLAN
 * $Id: wav.c 8862 2004-09-30 17:21:40Z gbazin $
 *
 * Authors: Gildas Bazin <gbazin@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., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
 *****************************************************************************/
/*****************************************************************************
 * Preamble
 *****************************************************************************/
#include <stdlib.h>
#include <vlc/vlc.h>
#include <vlc/aout.h>
#include <vlc/sout.h>
#include "codecs.h"
/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Open   ( vlc_object_t * );
static void Close  ( vlc_object_t * );
vlc_module_begin();
    set_description( _("WAV muxer") );
    set_capability( "sout mux", 5 );
    set_callbacks( Open, Close );
    add_shortcut( "wav" );
vlc_module_end();
/*****************************************************************************
 * Exported prototypes
 *****************************************************************************/
static int Control  ( sout_mux_t *, int, va_list );
static int AddStream( sout_mux_t *, sout_input_t * );
static int DelStream( sout_mux_t *, sout_input_t * );
static int Mux      ( sout_mux_t * );
#define MAX_CHANNELS 6
struct sout_mux_sys_t
{
    vlc_bool_t b_used;
    vlc_bool_t b_header;
    vlc_bool_t b_ext;
    uint32_t i_data;
    /* Wave header for the output data */
    uint32_t waveheader[5];
    WAVEFORMATEXTENSIBLE waveformat;
    uint32_t waveheader2[2];
    uint32_t i_channel_mask;
    vlc_bool_t b_chan_reorder;              /* do we need channel reordering */
    int pi_chan_table[AOUT_CHAN_MAX];
};
static const uint32_t pi_channels_src[] =
    { AOUT_CHAN_LEFT, AOUT_CHAN_RIGHT,
      AOUT_CHAN_MIDDLELEFT, AOUT_CHAN_MIDDLERIGHT,
      AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT,
      AOUT_CHAN_CENTER, AOUT_CHAN_LFE, 0 };
static const uint32_t pi_channels_in[] =
    { WAVE_SPEAKER_FRONT_LEFT, WAVE_SPEAKER_FRONT_RIGHT,
      WAVE_SPEAKER_SIDE_LEFT, WAVE_SPEAKER_SIDE_RIGHT,
      WAVE_SPEAKER_BACK_LEFT, WAVE_SPEAKER_BACK_RIGHT,
      WAVE_SPEAKER_FRONT_CENTER, WAVE_SPEAKER_LOW_FREQUENCY, 0 };
static const uint32_t pi_channels_out[] =
    { WAVE_SPEAKER_FRONT_LEFT, WAVE_SPEAKER_FRONT_RIGHT,
      WAVE_SPEAKER_FRONT_CENTER, WAVE_SPEAKER_LOW_FREQUENCY,
      WAVE_SPEAKER_BACK_LEFT, WAVE_SPEAKER_BACK_RIGHT,
      WAVE_SPEAKER_SIDE_LEFT, WAVE_SPEAKER_SIDE_RIGHT, 0 };
/*****************************************************************************
 * Open:
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    sout_mux_t *p_mux = (sout_mux_t*)p_this;
    sout_mux_sys_t  *p_sys;
    p_mux->pf_control  = Control;
    p_mux->pf_addstream = AddStream;
    p_mux->pf_delstream = DelStream;
    p_mux->pf_mux       = Mux;
    p_mux->p_sys = p_sys = malloc( sizeof( sout_mux_sys_t ) );
    p_sys->b_used   = VLC_FALSE;
    p_sys->b_header = VLC_TRUE;
    p_sys->i_data   = 0;
    p_sys->b_chan_reorder = 0;
    return VLC_SUCCESS;
}
/*****************************************************************************
 * Close:
 *****************************************************************************/
static void Close( vlc_object_t * p_this )
{
    sout_mux_t *p_mux = (sout_mux_t*)p_this;
    sout_mux_sys_t *p_sys = p_mux->p_sys;
    free( p_sys );
}
static int Control( sout_mux_t *p_mux, int i_query, va_list args )
{
    vlc_bool_t *pb_bool;
    char **ppsz;
   switch( i_query )
   {
       case MUX_CAN_ADD_STREAM_WHILE_MUXING:
           pb_bool = (vlc_bool_t*)va_arg( args, vlc_bool_t * );
           *pb_bool = VLC_FALSE;
           return VLC_SUCCESS;
       case MUX_GET_ADD_STREAM_WAIT:
           pb_bool = (vlc_bool_t*)va_arg( args, vlc_bool_t * );
           *pb_bool = VLC_TRUE;
           return VLC_SUCCESS;
       case MUX_GET_MIME:
           ppsz = (char**)va_arg( args, char ** );
           *ppsz = strdup( "audio/wav" );
           return VLC_SUCCESS;
        default:
            return VLC_EGENERIC;
   }
}
static int AddStream( sout_mux_t *p_mux, sout_input_t *p_input )
{
    GUID subformat_guid = {0, 0, 0x10,{0x80, 0, 0, 0xaa, 0, 0x38, 0x9b, 0x71}};
    sout_mux_sys_t *p_sys = p_mux->p_sys;
    WAVEFORMATEX *p_waveformat = &p_sys->waveformat.Format;
    int i_bytes_per_sample, i_format, i;
    vlc_bool_t b_ext;
    if( p_input->p_fmt->i_cat != AUDIO_ES )
    {
        msg_Dbg( p_mux, "not an audio stream" );
        return VLC_EGENERIC;
    }
    if( p_sys->b_used )
    {
        msg_Dbg( p_mux, "can't add more than 1 stream" );
        return VLC_EGENERIC;
    }
    msg_Dbg( p_mux, "adding input %i channels, %iHz",
             p_input->p_fmt->audio.i_channels,
             p_input->p_fmt->audio.i_rate );
    p_sys->i_channel_mask = 0;
    if( p_input->p_fmt->audio.i_physical_channels )
    {
        for( i = 0; i < sizeof(pi_channels_in)/sizeof(uint32_t); i++ )
        {
            if( p_input->p_fmt->audio.i_physical_channels & pi_channels_src[i])
                p_sys->i_channel_mask |= pi_channels_in[i];
        }
        p_sys->b_chan_reorder =
            aout_CheckChannelReorder( pi_channels_in, pi_channels_out,
                                      p_sys->i_channel_mask,
                                      p_input->p_fmt->audio.i_channels,
                                      p_sys->pi_chan_table );
        msg_Dbg( p_mux, "channel mask: %x, reordering: %i",
                 p_sys->i_channel_mask, (int)p_sys->b_chan_reorder );
    }
    i_format = p_input->p_fmt->i_codec == VLC_FOURCC('f', 'l', '3', '2') ?
        WAVE_FORMAT_IEEE_FLOAT : WAVE_FORMAT_PCM;
    b_ext = p_sys->b_ext = p_input->p_fmt->audio.i_channels > 2;
    /* Build a WAV header for the output data */
    p_sys->waveheader[0] = VLC_FOURCC('R', 'I', 'F', 'F'); /* MainChunkID */
    SetDWLE( &p_sys->waveheader[1], 0 ); /* Length */
    p_sys->waveheader[2] = VLC_FOURCC('W', 'A', 'V', 'E'); /* ChunkTypeID */
    p_sys->waveheader[3] = VLC_FOURCC('f', 'm', 't', ' '); /* SubChunkID */
    SetDWLE( &p_sys->waveheader[4], b_ext ? 40 : 16 ); /* SubChunkLength */
    p_sys->waveheader2[0] = VLC_FOURCC('d', 'a', 't', 'a'); /* DataChunkID */
    SetDWLE( &p_sys->waveheader2[1], 0 ); /* DataLength */
    /* Build a WAVEVFORMAT header for the output data */
    memset( &p_sys->waveformat, 0, sizeof(WAVEFORMATEXTENSIBLE) );
    SetWLE( &p_waveformat->wFormatTag,
            b_ext ? WAVE_FORMAT_EXTENSIBLE : i_format );
    SetWLE( &p_waveformat->nChannels,
            p_input->p_fmt->audio.i_channels );
    SetDWLE( &p_waveformat->nSamplesPerSec, p_input->p_fmt->audio.i_rate );
    i_bytes_per_sample = p_input->p_fmt->audio.i_channels *
        p_input->p_fmt->audio.i_bitspersample / 8;
    SetDWLE( &p_waveformat->nAvgBytesPerSec,
             i_bytes_per_sample * p_input->p_fmt->audio.i_rate );
    SetWLE( &p_waveformat->nBlockAlign, i_bytes_per_sample );
    SetWLE( &p_waveformat->wBitsPerSample,
            p_input->p_fmt->audio.i_bitspersample );
    SetWLE( &p_waveformat->cbSize, 22 );
    SetWLE( &p_sys->waveformat.Samples.wValidBitsPerSample,
            p_input->p_fmt->audio.i_bitspersample );
    SetDWLE( &p_sys->waveformat.dwChannelMask,
             p_sys->i_channel_mask );
    p_sys->waveformat.SubFormat = subformat_guid;
    p_sys->waveformat.SubFormat.Data1 = i_format;
    p_sys->b_used = VLC_TRUE;
    return VLC_SUCCESS;
}
static block_t *GetHeader( sout_mux_t *p_mux )
{
    sout_mux_sys_t *p_sys = p_mux->p_sys;
    block_t *p_block =
        block_New( p_mux, sizeof( WAVEFORMATEXTENSIBLE ) + 7 * 4 );
    SetDWLE( &p_sys->waveheader[1],
             20 + (p_sys->b_ext ? 40 : 16) + p_sys->i_data ); /* Length */
    SetDWLE( &p_sys->waveheader2[1], p_sys->i_data ); /* DataLength */
    memcpy( p_block->p_buffer, &p_sys->waveheader, 5 * 4 );
    memcpy( p_block->p_buffer + 5 * 4, &p_sys->waveformat,
            sizeof( WAVEFORMATEXTENSIBLE ) );
    memcpy( p_block->p_buffer + 5 * 4 +
            (p_sys->b_ext ? sizeof( WAVEFORMATEXTENSIBLE ) : 16),
            &p_sys->waveheader2, 2 * 4 );
    if( !p_sys->b_ext ) p_block->i_buffer -= 24;
    return p_block;
}
static int DelStream( sout_mux_t *p_mux, sout_input_t *p_input )
{
    msg_Dbg( p_mux, "removing input" );
    msg_Dbg( p_mux, "writing header data" );
    if( !sout_AccessOutSeek( p_mux->p_access, 0 ) )
    {
        sout_AccessOutWrite( p_mux->p_access, GetHeader( p_mux ) );
    }
    return VLC_SUCCESS;
}
static int Mux( sout_mux_t *p_mux )
{
    sout_mux_sys_t *p_sys = p_mux->p_sys;
    sout_input_t *p_input;
    if( !p_mux->i_nb_inputs ) return VLC_SUCCESS;
    if( p_sys->b_header )
    {
        msg_Dbg( p_mux, "writing header data" );
        sout_AccessOutWrite( p_mux->p_access, GetHeader( p_mux ) );
    }
    p_sys->b_header = VLC_FALSE;
    p_input = p_mux->pp_inputs[0];
    while( p_input->p_fifo->i_depth > 0 )
    {
        block_t *p_block = block_FifoGet( p_input->p_fifo );
        p_sys->i_data += p_block->i_buffer;
        /* Do the channel reordering */
        if( p_sys->b_chan_reorder )
            aout_ChannelReorder( p_block->p_buffer, p_block->i_buffer,
                                 p_input->p_fmt->audio.i_channels,
                                 p_sys->pi_chan_table,
                                 p_input->p_fmt->audio.i_bitspersample );
        sout_AccessOutWrite( p_mux->p_access, p_block );
    }
    return VLC_SUCCESS;
}

						