Build VLC aliases cleanly (don't need to parse argv[0])
[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
28 #include <vlc/vlc.h>
29 #include <vlc_aout.h>
30
31 /*****************************************************************************
32  * Local prototypes
33  *****************************************************************************/
34 static int  Create    ( vlc_object_t * );
35
36 static void DoWork    ( aout_instance_t *, aout_buffer_t * );
37
38 /*****************************************************************************
39  * Module descriptor
40  *****************************************************************************/
41 vlc_module_begin();
42     set_category( CAT_AUDIO );
43     set_subcategory( SUBCAT_AUDIO_MISC );
44     set_description( _("Float32 audio mixer") );
45     set_capability( "audio mixer", 10 );
46     set_callbacks( Create, NULL );
47 vlc_module_end();
48
49 /*****************************************************************************
50  * Create: allocate mixer
51  *****************************************************************************/
52 static int Create( vlc_object_t *p_this )
53 {
54     aout_instance_t * p_aout = (aout_instance_t *)p_this;
55
56     if ( p_aout->mixer.mixer.i_format != VLC_FOURCC('f','l','3','2') )
57     {
58         return -1;
59     }
60
61     /* Use the trivial mixer when we can */
62     if ( p_aout->i_nb_inputs == 1 && p_aout->mixer.f_multiplier == 1.0 )
63     {
64         int i;
65         for( i = 0; i < p_aout->i_nb_inputs; i++ )
66         {
67             if( p_aout->pp_inputs[i]->f_multiplier != 1.0 )
68                 break;
69         }
70         if( i >= p_aout->i_nb_inputs )
71             return -1;
72     }
73
74     p_aout->mixer.pf_do_work = DoWork;
75     return 0;
76 }
77
78 /*****************************************************************************
79  * ScaleWords: prepare input words for averaging
80  *****************************************************************************/
81 static void ScaleWords( float * p_out, const float * p_in, size_t i_nb_words,
82                         int i_nb_inputs, float f_multiplier )
83 {
84     int i;
85     f_multiplier /= i_nb_inputs;
86
87     for ( i = i_nb_words; i--; )
88     {
89         *p_out++ = *p_in++ * f_multiplier;
90     }
91 }
92
93 /*****************************************************************************
94  * MeanWords: average input words
95  *****************************************************************************/
96 static void MeanWords( float * p_out, const float * p_in, size_t i_nb_words,
97                        int i_nb_inputs, float f_multiplier )
98 {
99     int i;
100     f_multiplier /= i_nb_inputs;
101
102     for ( i = i_nb_words; i--; )
103     {
104         *p_out++ += *p_in++ * f_multiplier;
105     }
106 }
107
108 /*****************************************************************************
109  * DoWork: mix a new output buffer
110  *****************************************************************************
111  * Terminology : in this function a word designates a single float32, eg.
112  * a stereo sample is consituted of two words.
113  *****************************************************************************/
114 static void DoWork( aout_instance_t * p_aout, aout_buffer_t * p_buffer )
115 {
116     const int i_nb_inputs = p_aout->i_nb_inputs;
117     const float f_multiplier_global = p_aout->mixer.f_multiplier;
118     const int i_nb_channels = aout_FormatNbChannels( &p_aout->mixer.mixer );
119     int i_input;
120
121     for ( i_input = 0; i_input < i_nb_inputs; i_input++ )
122     {
123         int i_nb_words = p_buffer->i_nb_samples * i_nb_channels;
124         aout_input_t * p_input = p_aout->pp_inputs[i_input];
125         float f_multiplier = f_multiplier_global * p_input->f_multiplier;
126
127         float * p_out = (float *)p_buffer->p_buffer;
128         float * p_in = (float *)p_input->p_first_byte_to_mix;
129
130         if ( p_input->b_error ) continue;
131
132         for ( ; ; )
133         {
134             ptrdiff_t i_available_words = (
135                  (float *)p_input->fifo.p_first->p_buffer - p_in)
136                                    + p_input->fifo.p_first->i_nb_samples
137                                    * i_nb_channels;
138
139             if ( i_available_words < i_nb_words )
140             {
141                 aout_buffer_t * p_old_buffer;
142
143                 if ( i_available_words > 0 )
144                 {
145                     if ( !i_input )
146                     {
147                         ScaleWords( p_out, p_in, i_available_words,
148                                     i_nb_inputs, f_multiplier );
149                     }
150                     else
151                     {
152                         MeanWords( p_out, p_in, i_available_words,
153                                    i_nb_inputs, f_multiplier );
154                     }
155                 }
156
157                 i_nb_words -= i_available_words;
158                 p_out += i_available_words;
159
160                 /* Next buffer */
161                 p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
162                 aout_BufferFree( p_old_buffer );
163                 if ( p_input->fifo.p_first == NULL )
164                 {
165                     msg_Err( p_aout, "internal amix error" );
166                     return;
167                 }
168                 p_in = (float *)p_input->fifo.p_first->p_buffer;
169             }
170             else
171             {
172                 if ( i_nb_words > 0 )
173                 {
174                     if ( !i_input )
175                     {
176                         ScaleWords( p_out, p_in, i_nb_words, i_nb_inputs,
177                                     f_multiplier );
178                     }
179                     else
180                     {
181                         MeanWords( p_out, p_in, i_nb_words, i_nb_inputs,
182                                    f_multiplier );
183                     }
184                 }
185                 p_input->p_first_byte_to_mix = (void *)(p_in
186                                             + i_nb_words);
187                 break;
188             }
189         }
190     }
191 }
192