s16tofixed32.c
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上传日期:2009-03-27
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文件大小:4k
- /*****************************************************************************
- * s16tofixed32.c : converter from signed 16 bits integer to fixed 32
- *****************************************************************************
- * Copyright (C) 2002 VideoLAN
- * $Id: s16tofixed32.c 6961 2004-03-05 17:34:23Z sam $
- *
- * Authors: Marc Ariberti <marcari@videolan.ord>
- *
- * 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 <string.h>
- #include <vlc/vlc.h>
- #include "audio_output.h"
- #include "aout_internal.h"
- /*****************************************************************************
- * Local prototypes
- *****************************************************************************/
- static int Create ( vlc_object_t * );
- static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
- aout_buffer_t * );
- /*****************************************************************************
- * Module descriptor
- *****************************************************************************/
- vlc_module_begin();
- set_description( _("audio filter for s16->fixed32 conversion") );
- set_capability( "audio filter", 15 );
- set_callbacks( Create, NULL );
- vlc_module_end();
- /*****************************************************************************
- * Create: allocate filter
- *****************************************************************************
- * This function allocates and initializes a s16->fixed32 audio filter.
- *****************************************************************************/
- static int Create( vlc_object_t *p_this )
- {
- aout_filter_t * p_filter = (aout_filter_t *)p_this;
- if ( p_filter->output.i_format != VLC_FOURCC('f','i','3','2')
- || p_filter->input.i_format != AOUT_FMT_S16_NE )
- {
- return -1;
- }
- if ( !AOUT_FMTS_SIMILAR( &p_filter->input, &p_filter->output ) )
- {
- return -1;
- }
- p_filter->pf_do_work = DoWork;
- p_filter->b_in_place = 1;
- return 0;
- }
- /*****************************************************************************
- * DoWork: convert a buffer
- *****************************************************************************/
- static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
- aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
- {
- int i = p_in_buf->i_nb_samples * aout_FormatNbChannels( &p_filter->input );
- /* We start from the end because b_in_place is true */
- int16_t * p_in = (int16_t *)p_in_buf->p_buffer + i - 1;
- vlc_fixed_t * p_out = (vlc_fixed_t *)p_out_buf->p_buffer + i - 1;
- while( i-- )
- {
- *p_out = (vlc_fixed_t)( (int32_t)(*p_in) * (FIXED32_ONE >> 16) );
- p_in--; p_out--;
- }
- p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
- p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes
- * sizeof(vlc_fixed_t) / sizeof(int16_t);
- }