1 /*****************************************************************************
2 * float32tos16.c : converter from float32 to signed 16 bits integer
3 *****************************************************************************
4 * Copyright (C) 2002 the VideoLAN team
7 * Authors: Christophe Massiot <massiot@via.ecp.fr>
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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, 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_category( CAT_AUDIO );
47 set_subcategory( SUBCAT_AUDIO_MISC );
48 set_description( _("audio filter for float32->s16 conversion") );
49 set_capability( "audio filter", 1 );
50 set_callbacks( Create, NULL );
53 /*****************************************************************************
54 * Create: allocate trivial mixer
55 *****************************************************************************/
56 static int Create( vlc_object_t *p_this )
58 aout_filter_t * p_filter = (aout_filter_t *)p_this;
60 if ( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
61 || p_filter->output.i_format != AOUT_FMT_S16_NE )
66 if ( !AOUT_FMTS_SIMILAR( &p_filter->input, &p_filter->output ) )
71 p_filter->pf_do_work = DoWork;
72 p_filter->b_in_place = 1;
77 /*****************************************************************************
78 * DoWork: convert a buffer
79 *****************************************************************************/
80 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
81 aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
84 float * p_in = (float *)p_in_buf->p_buffer;
85 int16_t * p_out = (int16_t *)p_out_buf->p_buffer;
87 for ( i = p_in_buf->i_nb_samples
88 * aout_FormatNbChannels( &p_filter->input ); i-- ; )
92 if ( *p_in >= 1.0 ) *p_out = 32767;
93 else if ( *p_in < -1.0 ) *p_out = -32768;
94 else *p_out = *p_in * 32768.0;
96 /* This is walken's trick based on IEEE float format. */
97 union { float f; int32_t i; } u;
99 if ( u.i > 0x43c07fff ) *p_out = 32767;
100 else if ( u.i < 0x43bf8000 ) *p_out = -32768;
101 else *p_out = u.i - 0x43c00000;
106 p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
107 p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes / 2;