Make it possible to force a distro.mak to use. This is helpfull in cross-compile...
[vlc.git] / modules / audio_mixer / float32.c
1 /*****************************************************************************
2  * float32.c : precise float32 audio mixer implementation
3  *****************************************************************************
4  * Copyright (C) 2002 the VideoLAN team
5  * $Id$
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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
22  *****************************************************************************/
23
24 /*****************************************************************************
25  * Preamble
26  *****************************************************************************/
27 #include <stdlib.h>                                      /* malloc(), free() */
28 #include <string.h>
29
30 #include <vlc/vlc.h>
31 #include <vlc_aout.h>
32
33 /*****************************************************************************
34  * Local prototypes
35  *****************************************************************************/
36 static int  Create    ( vlc_object_t * );
37
38 static void DoWork    ( aout_instance_t *, aout_buffer_t * );
39
40 /*****************************************************************************
41  * Module descriptor
42  *****************************************************************************/
43 vlc_module_begin();
44     set_category( CAT_AUDIO );
45     set_subcategory( SUBCAT_AUDIO_MISC );
46     set_description( _("Float32 audio mixer") );
47     set_capability( "audio mixer", 10 );
48     set_callbacks( Create, NULL );
49 vlc_module_end();
50
51 /*****************************************************************************
52  * Create: allocate 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 != VLC_FOURCC('f','l','3','2') )
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     float f_multiplier = p_aout->mixer.f_multiplier;
114     int i_input;
115     int i_nb_channels = aout_FormatNbChannels( &p_aout->mixer.mixer );
116
117     for ( i_input = 0; i_input < i_nb_inputs; i_input++ )
118     {
119         int i_nb_words = p_buffer->i_nb_samples * i_nb_channels;
120         aout_input_t * p_input = p_aout->pp_inputs[i_input];
121         float * p_out = (float *)p_buffer->p_buffer;
122         float * p_in = (float *)p_input->p_first_byte_to_mix;
123
124         if ( p_input->b_error ) continue;
125
126         for ( ; ; )
127         {
128             ptrdiff_t i_available_words = (
129                  (float *)p_input->fifo.p_first->p_buffer - p_in)
130                                    + p_input->fifo.p_first->i_nb_samples
131                                    * i_nb_channels;
132
133             if ( i_available_words < i_nb_words )
134             {
135                 aout_buffer_t * p_old_buffer;
136
137                 if ( i_available_words > 0 )
138                 {
139                     if ( !i_input )
140                     {
141                         ScaleWords( p_out, p_in, i_available_words,
142                                     i_nb_inputs, f_multiplier );
143                     }
144                     else
145                     {
146                         MeanWords( p_out, p_in, i_available_words,
147                                    i_nb_inputs, f_multiplier );
148                     }
149                 }
150
151                 i_nb_words -= i_available_words;
152                 p_out += i_available_words;
153
154                 /* Next buffer */
155                 p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
156                 aout_BufferFree( p_old_buffer );
157                 if ( p_input->fifo.p_first == NULL )
158                 {
159                     msg_Err( p_aout, "internal amix error" );
160                     return;
161                 }
162                 p_in = (float *)p_input->fifo.p_first->p_buffer;
163             }
164             else
165             {
166                 if ( i_nb_words > 0 )
167                 {
168                     if ( !i_input )
169                     {
170                         ScaleWords( p_out, p_in, i_nb_words, i_nb_inputs,
171                                     f_multiplier );
172                     }
173                     else
174                     {
175                         MeanWords( p_out, p_in, i_nb_words, i_nb_inputs,
176                                    f_multiplier );
177                     }
178                 }
179                 p_input->p_first_byte_to_mix = (void *)(p_in
180                                             + i_nb_words);
181                 break;
182             }
183         }
184     }
185 }
186