Fixed vc1 packetizer.
[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 #ifdef HAVE_CONFIG_H
29 # include "config.h"
30 #endif
31
32 #include <stddef.h>
33 #include <vlc_common.h>
34 #include <vlc_plugin.h>
35 #include <vlc_aout.h>
36
37 /*****************************************************************************
38  * Local prototypes
39  *****************************************************************************/
40 static int  Create    ( vlc_object_t * );
41
42 static void DoWork    ( aout_instance_t *, aout_buffer_t * );
43
44 /*****************************************************************************
45  * Module descriptor
46  *****************************************************************************/
47 vlc_module_begin ()
48     set_category( CAT_AUDIO )
49     set_subcategory( SUBCAT_AUDIO_MISC )
50     set_description( N_("Float32 audio mixer") )
51     set_capability( "audio mixer", 10 )
52     set_callbacks( Create, NULL )
53 vlc_module_end ()
54
55 /*****************************************************************************
56  * Create: allocate mixer
57  *****************************************************************************/
58 static int Create( vlc_object_t *p_this )
59 {
60     aout_instance_t * p_aout = (aout_instance_t *)p_this;
61
62     if ( p_aout->mixer.mixer.i_format != VLC_FOURCC('f','l','3','2') )
63     {
64         return -1;
65     }
66
67     /* Use the trivial mixer when we can */
68     if ( p_aout->i_nb_inputs == 1 && p_aout->mixer.f_multiplier == 1.0 )
69     {
70         int i;
71         for( i = 0; i < p_aout->i_nb_inputs; i++ )
72         {
73             if( p_aout->pp_inputs[i]->f_multiplier != 1.0 )
74                 break;
75         }
76         if( i >= p_aout->i_nb_inputs )
77             return -1;
78     }
79
80     p_aout->mixer.pf_do_work = DoWork;
81     return 0;
82 }
83
84 /*****************************************************************************
85  * ScaleWords: prepare input words for averaging
86  *****************************************************************************/
87 static void ScaleWords( float * p_out, const float * p_in, size_t i_nb_words,
88                         int i_nb_inputs, float f_multiplier )
89 {
90     int i;
91     f_multiplier /= i_nb_inputs;
92
93     for ( i = i_nb_words; i--; )
94     {
95         *p_out++ = *p_in++ * f_multiplier;
96     }
97 }
98
99 /*****************************************************************************
100  * MeanWords: average input words
101  *****************************************************************************/
102 static void MeanWords( float * p_out, const float * p_in, size_t i_nb_words,
103                        int i_nb_inputs, float f_multiplier )
104 {
105     int i;
106     f_multiplier /= i_nb_inputs;
107
108     for ( i = i_nb_words; i--; )
109     {
110         *p_out++ += *p_in++ * f_multiplier;
111     }
112 }
113
114 /*****************************************************************************
115  * DoWork: mix a new output buffer
116  *****************************************************************************
117  * Terminology : in this function a word designates a single float32, eg.
118  * a stereo sample is consituted of two words.
119  *****************************************************************************/
120 static void DoWork( aout_instance_t * p_aout, aout_buffer_t * p_buffer )
121 {
122     const int i_nb_inputs = p_aout->i_nb_inputs;
123     const float f_multiplier_global = p_aout->mixer.f_multiplier;
124     const int i_nb_channels = aout_FormatNbChannels( &p_aout->mixer.mixer );
125     int i_input;
126
127     for ( i_input = 0; i_input < i_nb_inputs; i_input++ )
128     {
129         int i_nb_words = p_buffer->i_nb_samples * i_nb_channels;
130         aout_input_t * p_input = p_aout->pp_inputs[i_input];
131         float f_multiplier = f_multiplier_global * p_input->f_multiplier;
132
133         float * p_out = (float *)p_buffer->p_buffer;
134         float * p_in = (float *)p_input->p_first_byte_to_mix;
135
136         if ( p_input->b_error || p_input->b_paused )
137             continue;
138
139         for ( ; ; )
140         {
141             ptrdiff_t i_available_words = (
142                  (float *)p_input->fifo.p_first->p_buffer - p_in)
143                                    + p_input->fifo.p_first->i_nb_samples
144                                    * i_nb_channels;
145
146             if ( i_available_words < i_nb_words )
147             {
148                 aout_buffer_t * p_old_buffer;
149
150                 if ( i_available_words > 0 )
151                 {
152                     if ( !i_input )
153                     {
154                         ScaleWords( p_out, p_in, i_available_words,
155                                     i_nb_inputs, f_multiplier );
156                     }
157                     else
158                     {
159                         MeanWords( p_out, p_in, i_available_words,
160                                    i_nb_inputs, f_multiplier );
161                     }
162                 }
163
164                 i_nb_words -= i_available_words;
165                 p_out += i_available_words;
166
167                 /* Next buffer */
168                 p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
169                 aout_BufferFree( p_old_buffer );
170                 if ( p_input->fifo.p_first == NULL )
171                 {
172                     msg_Err( p_aout, "internal amix error" );
173                     return;
174                 }
175                 p_in = (float *)p_input->fifo.p_first->p_buffer;
176             }
177             else
178             {
179                 if ( i_nb_words > 0 )
180                 {
181                     if ( !i_input )
182                     {
183                         ScaleWords( p_out, p_in, i_nb_words, i_nb_inputs,
184                                     f_multiplier );
185                     }
186                     else
187                     {
188                         MeanWords( p_out, p_in, i_nb_words, i_nb_inputs,
189                                    f_multiplier );
190                     }
191                 }
192                 p_input->p_first_byte_to_mix = (void *)(p_in
193                                             + i_nb_words);
194                 break;
195             }
196         }
197     }
198 }
199