* Fixed a variable overflow bug in the audio output.
[vlc.git] / modules / audio_mixer / trivial.c
1 /*****************************************************************************
2  * trivial.c : trivial mixer plug-in (1 input, no downmixing)
3  *****************************************************************************
4  * Copyright (C) 2002 VideoLAN
5  * $Id: trivial.c,v 1.4 2002/08/12 22:12:50 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( _("trivial aout mixer module") );
47     set_capability( "audio mixer", 1 );
48     add_shortcut( "trivial" );
49     set_callbacks( Create, NULL );
50 vlc_module_end();
51
52 /*****************************************************************************
53  * Create: allocate trivial mixer
54  *****************************************************************************/
55 static int Create( vlc_object_t *p_this )
56 {
57     aout_instance_t * p_aout = (aout_instance_t *)p_this;
58
59     if ( p_aout->mixer.output.i_format != AOUT_FMT_FLOAT32
60           && p_aout->mixer.output.i_format != AOUT_FMT_FIXED32 )
61     {
62         return -1;
63     }
64
65     p_aout->mixer.pf_do_work = DoWork;
66
67     return 0;
68 }
69
70 /*****************************************************************************
71  * SparseCopy: trivially downmix or upmix a buffer
72  *****************************************************************************/
73 static void SparseCopy( u32 * p_dest, const u32 * p_src, size_t i_len,
74                         int i_output_stride, int i_input_stride )
75 {
76     int i;
77     for ( i = 0; i < i_len; i++ )
78     {
79         int j;
80         for ( j = 0; j < i_output_stride; j++ )
81         {
82             p_dest[j] = p_src[j];
83         }
84         p_src += i_input_stride;
85         p_dest += i_output_stride;
86     }
87 }
88
89 /*****************************************************************************
90  * DoWork: mix a new output buffer
91  *****************************************************************************/
92 static void DoWork( aout_instance_t * p_aout, aout_buffer_t * p_buffer )
93 {
94     aout_input_t * p_input = p_aout->pp_inputs[0];
95
96     if ( p_input->input.i_channels == p_aout->mixer.output.i_channels )
97     {
98         int i_nb_bytes = p_buffer->i_nb_samples * sizeof(u32)
99                           * p_input->input.i_channels;
100         byte_t * p_in = (p_input->p_first_byte_to_mix == NULL) ?
101                         p_input->fifo.p_first->p_buffer :
102                         p_input->p_first_byte_to_mix;
103         byte_t * p_out = p_buffer->p_buffer;
104
105         for ( ; ; )
106         {
107             ptrdiff_t i_available_bytes = (p_input->fifo.p_first->p_buffer
108                                            - p_in)
109                                            + p_input->fifo.p_first->i_nb_samples
110                                               * sizeof(u32)
111                                               * p_input->input.i_channels;
112
113             if ( i_available_bytes < i_nb_bytes )
114             {
115                 aout_buffer_t * p_old_buffer;
116
117                 if ( i_available_bytes > 0 )
118                     p_aout->p_vlc->pf_memcpy( p_out, p_in, i_available_bytes );
119                 i_nb_bytes -= i_available_bytes;
120                 p_out += i_available_bytes;
121
122                 /* Next buffer */
123                 p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
124                 aout_BufferFree( p_old_buffer );
125                 if ( p_input->fifo.p_first == NULL )
126                 {
127                     msg_Err( p_aout, "internal amix error" );
128                     return;
129                 }
130                 p_in = p_input->fifo.p_first->p_buffer;
131             }
132             else
133             {
134                 p_aout->p_vlc->pf_memcpy( p_out, p_in, i_nb_bytes );
135                 p_input->p_first_byte_to_mix = p_in + i_nb_bytes;
136                 break;
137             }
138         }
139     }
140     else
141     {
142         /* Downmixing or upmixing. */
143         int i_nb_samples = p_buffer->i_nb_samples;
144         u32 * p_in = (p_input->p_first_byte_to_mix == NULL) ?
145                      (u32 *)p_input->fifo.p_first->p_buffer :
146                      (u32 *)p_input->p_first_byte_to_mix;
147         u32 * p_out = (u32 *)p_buffer->p_buffer;
148
149         if ( p_input->input.i_channels < p_aout->mixer.output.i_channels )
150         {
151             /* Zero out the destination buffer, to avoid static on unavailable
152              * channels. */
153             memset( p_buffer->p_buffer, 0,
154                     p_buffer->i_nb_samples * sizeof(u32)
155                      * p_aout->mixer.output.i_channels );
156         }
157
158         for ( ; ; )
159         {
160             ptrdiff_t i_available_bytes = (p_input->fifo.p_first->p_buffer
161                                            - (byte_t *)p_in)
162                                            + p_input->fifo.p_first->i_nb_samples
163                                               * sizeof(u32)
164                                               * p_input->input.i_channels;
165             int i_available_samples = i_available_bytes
166                                        / p_input->input.i_channels
167                                        / sizeof(u32);
168
169             if ( i_available_samples < i_nb_samples )
170             {
171                 aout_buffer_t * p_old_buffer;
172
173                 if ( i_available_samples > 0 )
174                     SparseCopy( p_out, p_in, i_available_samples,
175                                 p_aout->mixer.output.i_channels,
176                                 p_input->input.i_channels );
177                 i_nb_samples -= i_available_samples;
178                 p_out += i_available_samples * p_aout->mixer.output.i_channels;
179
180                 /* Next buffer */
181                 p_old_buffer = aout_FifoPop( p_aout, &p_input->fifo );
182                 aout_BufferFree( p_old_buffer );
183                 if ( p_input->fifo.p_first == NULL )
184                 {
185                     msg_Err( p_aout, "internal amix error" );
186                     return;
187                 }
188                 p_in = (u32 *)p_input->fifo.p_first->p_buffer;
189             }
190             else
191             {
192                 SparseCopy( p_out, p_in, i_nb_samples,
193                             p_aout->mixer.output.i_channels,
194                             p_input->input.i_channels );
195                 p_input->p_first_byte_to_mix = (byte_t *)p_in
196                                + i_nb_samples * p_input->input.i_channels
197                                   * sizeof(u32);
198                 break;
199             }
200         }
201     }
202 }
203