* configure.in: Fixed detection of Qt-embedded.
[vlc.git] / modules / audio_mixer / float32.c
1 /*****************************************************************************
2  * float32.c : precise float32 audio mixer implementation
3  *****************************************************************************
4  * Copyright (C) 2002 VideoLAN
5  * $Id: float32.c,v 1.2 2002/09/16 20:46:37 massiot Exp $
6  *
7  * Authors: Christophe Massiot <massiot@via.ecp.fr>
8  *
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.
13  * 
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.
18  *
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  *****************************************************************************/
23
24 /*****************************************************************************
25  * Preamble
26  *****************************************************************************/
27 #include <errno.h>
28 #include <stdlib.h>                                      /* malloc(), free() */
29 #include <string.h>
30
31 #include <vlc/vlc.h>
32 #include "audio_output.h"
33 #include "aout_internal.h"
34
35 /*****************************************************************************
36  * Local prototypes
37  *****************************************************************************/
38 static int  Create    ( vlc_object_t * );
39
40 static void DoWork    ( aout_instance_t *, aout_buffer_t * );
41
42 /*****************************************************************************
43  * Module descriptor
44  *****************************************************************************/
45 vlc_module_begin();
46     set_description( _("float32 audio mixer module") );
47     set_capability( "audio mixer", 10 );
48     set_callbacks( Create, NULL );
49 vlc_module_end();
50
51 /*****************************************************************************
52  * Create: allocate trivial mixer
53  *****************************************************************************/
54 static int Create( vlc_object_t *p_this )
55 {
56     aout_instance_t * p_aout = (aout_instance_t *)p_this;
57
58     if ( p_aout->mixer.mixer.i_format != AOUT_FMT_FLOAT32 )
59     {
60         return -1;
61     }
62
63     if ( p_aout->i_nb_inputs == 1 && p_aout->mixer.f_multiplier == 1.0 )
64     {
65         /* Tell the trivial mixer to go for it. */
66         return -1;
67     }
68
69     p_aout->mixer.pf_do_work = DoWork;
70
71     return 0;
72 }
73
74 /*****************************************************************************
75  * ScaleWords: prepare input words for averaging
76  *****************************************************************************/
77 static void ScaleWords( float * p_out, const float * p_in, size_t i_nb_words,
78                         int i_nb_inputs, float f_multiplier )
79 {
80     int i;
81     f_multiplier /= i_nb_inputs;
82
83     for ( i = i_nb_words; i--; )
84     {
85         *p_out++ = *p_in++ * f_multiplier;
86     }
87 }
88
89 /*****************************************************************************
90  * MeanWords: average input words
91  *****************************************************************************/
92 static void MeanWords( float * p_out, const float * p_in, size_t i_nb_words,
93                        int i_nb_inputs, float f_multiplier )
94 {
95     int i;
96     f_multiplier /= i_nb_inputs;
97
98     for ( i = i_nb_words; i--; )
99     {
100         *p_out++ += *p_in++ * f_multiplier;
101     }
102 }
103
104 /*****************************************************************************
105  * DoWork: mix a new output buffer
106  *****************************************************************************
107  * Terminology : in this function a word designates a single float32, eg.
108  * a stereo sample is consituted of two words.
109  *****************************************************************************/
110 static void DoWork( aout_instance_t * p_aout, aout_buffer_t * p_buffer )
111 {
112     int i_nb_inputs = p_aout->i_nb_inputs;
113     int i_input;
114
115     for ( i_input = 0; i_input < i_nb_inputs; i_input++ )
116     {
117         int i_nb_words = p_buffer->i_nb_samples
118                           * p_aout->mixer.mixer.i_channels;
119         aout_input_t * p_input = p_aout->pp_inputs[i_input];
120         float * p_out = (float *)p_buffer->p_buffer;
121         float * p_in = (float *)p_input->p_first_byte_to_mix;
122
123         for ( ; ; )
124         {
125             ptrdiff_t i_available_words = (
126                  (float *)p_input->fifo.p_first->p_buffer - p_in)
127                                    + p_input->fifo.p_first->i_nb_samples
128                                    * p_aout->mixer.mixer.i_channels;
129
130             if ( i_available_words < i_nb_words )
131             {
132                 aout_buffer_t * p_old_buffer;
133
134                 if ( i_available_words > 0 )
135                 {
136                     if ( !i_input )
137                     {
138                         ScaleWords( p_out, p_in, i_available_words,
139                                     i_nb_inputs, p_aout->mixer.f_multiplier );
140                     }
141                     else
142                     {
143                         MeanWords( p_out, p_in, i_available_words,
144                                    i_nb_inputs, p_aout->mixer.f_multiplier );
145                     }
146                 }
147
148                 i_nb_words -= i_available_words;
149                 p_out += i_available_words;
150
151                 /* Next buffer */
152                 p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
153                 aout_BufferFree( p_old_buffer );
154                 if ( p_input->fifo.p_first == NULL )
155                 {
156                     msg_Err( p_aout, "internal amix error" );
157                     return;
158                 }
159                 p_in = (float *)p_input->fifo.p_first->p_buffer;
160             }
161             else
162             {
163                 if ( i_nb_words > 0 )
164                 {
165                     if ( !i_input )
166                     {
167                         ScaleWords( p_out, p_in, i_nb_words, i_nb_inputs,
168                                     p_aout->mixer.f_multiplier );
169                     }
170                     else
171                     {
172                         MeanWords( p_out, p_in, i_nb_words, i_nb_inputs,
173                                    p_aout->mixer.f_multiplier );
174                     }
175                 }
176                 p_input->p_first_byte_to_mix = (void *)(p_in
177                                             + i_nb_words);
178                 break;
179             }
180         }
181     }
182 }
183