1 /*****************************************************************************
2 * u8tofloat32.c : converter from unsigned 8 bits integer to float32.
3 *****************************************************************************
4 * Copyright (C) 2002 VideoLAN
5 * $Id: u8tofloat32.c,v 1.3 2002/11/20 16:43:32 sam Exp $
7 * Authors: Gildas Bazin <gbazin@netcourrier.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
22 *****************************************************************************/
24 /*****************************************************************************
26 *****************************************************************************/
27 #include <stdlib.h> /* malloc(), free() */
31 #include "audio_output.h"
32 #include "aout_internal.h"
34 /*****************************************************************************
36 *****************************************************************************/
37 static int Create ( vlc_object_t * );
39 static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
42 /*****************************************************************************
44 *****************************************************************************/
46 set_description( _("audio filter for u8->float32 conversion") );
47 set_capability( "audio filter", 1 );
48 set_callbacks( Create, NULL );
51 /*****************************************************************************
52 * Create: create and initialize converter
53 *****************************************************************************/
54 static int Create( vlc_object_t *p_this )
56 aout_filter_t * p_filter = (aout_filter_t *)p_this;
58 if ( p_filter->input.i_format != VLC_FOURCC('u','8',' ',' ')
59 || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
64 if ( !AOUT_FMTS_SIMILAR( &p_filter->input, &p_filter->output ) )
69 p_filter->pf_do_work = DoWork;
70 p_filter->b_in_place = VLC_TRUE;
75 /*****************************************************************************
76 * DoWork: convert a buffer
77 *****************************************************************************/
78 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
79 aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
81 int i = p_in_buf->i_nb_samples * aout_FormatNbChannels( &p_filter->input );
83 /* We start from the end because b_in_place is true */
84 u8 * p_in = (u8 *)p_in_buf->p_buffer + i - 1;
85 float * p_out = (float *)p_out_buf->p_buffer + i - 1;
89 *p_out = ((float)*p_in -128) / 128.0;
93 p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
94 p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * sizeof(float);