1 /*****************************************************************************
2 * dolby.c : simple decoder for dolby surround encoded streams
3 *****************************************************************************
4 * Copyright (C) 2005, 2006 the VideoLAN team
7 * Authors: Boris Dorès <babal@via.ecp.fr>
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.
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.
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 *****************************************************************************/
24 /*****************************************************************************
26 *****************************************************************************/
33 #include <vlc_plugin.h>
36 /*****************************************************************************
38 *****************************************************************************/
39 static int Create ( vlc_object_t * );
40 static void Destroy ( vlc_object_t * );
42 static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
45 /*****************************************************************************
47 *****************************************************************************/
49 set_description( N_("Simple decoder for Dolby Surround encoded streams") );
50 set_shortname( N_("Dolby Surround decoder") );
51 set_category( CAT_INPUT );
52 set_subcategory( SUBCAT_INPUT_ACODEC );
53 set_capability( "audio filter", 5 );
54 set_callbacks( Create, Destroy );
57 /*****************************************************************************
58 * Internal data structures
59 *****************************************************************************/
60 struct aout_filter_sys_t
70 /* our internal channel order (WG-4 order) */
71 static const uint32_t pi_channels[] =
72 { AOUT_CHAN_LEFT, AOUT_CHAN_RIGHT, AOUT_CHAN_MIDDLELEFT, AOUT_CHAN_MIDDLERIGHT,
73 AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT, AOUT_CHAN_REARCENTER,
74 AOUT_CHAN_CENTER, AOUT_CHAN_LFE, 0 };
76 /*****************************************************************************
77 * Create: allocate headphone downmixer
78 *****************************************************************************/
79 static int Create( vlc_object_t *p_this )
83 aout_filter_t * p_filter = (aout_filter_t *)p_this;
85 /* Validate audio filter format */
86 if ( p_filter->input.i_physical_channels != (AOUT_CHAN_LEFT|AOUT_CHAN_RIGHT)
87 || ! ( p_filter->input.i_original_channels & AOUT_CHAN_DOLBYSTEREO )
88 || aout_FormatNbChannels( &p_filter->output ) <= 2
89 || ( p_filter->input.i_original_channels & ~AOUT_CHAN_DOLBYSTEREO )
90 != ( p_filter->output.i_original_channels & ~AOUT_CHAN_DOLBYSTEREO ) )
95 if ( p_filter->input.i_rate != p_filter->output.i_rate )
100 if ( p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
101 || p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
106 /* Allocate the memory needed to store the module's structure */
107 p_filter->p_sys = malloc( sizeof(struct aout_filter_sys_t) );
108 if ( p_filter->p_sys == NULL )
110 msg_Err( p_filter, "out of memory" );
113 p_filter->p_sys->i_left = -1;
114 p_filter->p_sys->i_center = -1;
115 p_filter->p_sys->i_right = -1;
116 p_filter->p_sys->i_rear_left = -1;
117 p_filter->p_sys->i_rear_center = -1;
118 p_filter->p_sys->i_rear_right = -1;
120 while ( pi_channels[i] )
122 if ( p_filter->output.i_physical_channels & pi_channels[i] )
124 switch ( pi_channels[i] )
127 p_filter->p_sys->i_left = i_offset;
129 case AOUT_CHAN_CENTER:
130 p_filter->p_sys->i_center = i_offset;
132 case AOUT_CHAN_RIGHT:
133 p_filter->p_sys->i_right = i_offset;
135 case AOUT_CHAN_REARLEFT:
136 p_filter->p_sys->i_rear_left = i_offset;
138 case AOUT_CHAN_REARCENTER:
139 p_filter->p_sys->i_rear_center = i_offset;
141 case AOUT_CHAN_REARRIGHT:
142 p_filter->p_sys->i_rear_right = i_offset;
150 p_filter->pf_do_work = DoWork;
151 p_filter->b_in_place = 0;
156 /*****************************************************************************
157 * Destroy: deallocate resources associated with headphone downmixer
158 *****************************************************************************/
159 static void Destroy( vlc_object_t *p_this )
161 aout_filter_t * p_filter = (aout_filter_t *)p_this;
163 if ( p_filter->p_sys != NULL )
165 free ( p_filter->p_sys );
166 p_filter->p_sys = NULL;
170 /*****************************************************************************
171 * DoWork: convert a buffer
172 *****************************************************************************/
173 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
174 aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
177 float * p_in = (float*) p_in_buf->p_buffer;
178 float * p_out = (float*) p_out_buf->p_buffer;
179 size_t i_nb_samples = p_in_buf->i_nb_samples;
180 size_t i_nb_channels = aout_FormatNbChannels( &p_filter->output );
182 p_out_buf->i_nb_samples = i_nb_samples;
183 p_out_buf->i_nb_bytes = sizeof(float) * i_nb_samples
184 * aout_FormatNbChannels( &p_filter->output );
185 memset ( p_out , 0 , p_out_buf->i_nb_bytes );
187 if ( p_filter->p_sys != NULL )
189 struct aout_filter_sys_t * p_sys = p_filter->p_sys;
190 size_t i_nb_rear = 0;
193 if ( p_sys->i_rear_left >= 0 )
197 if ( p_sys->i_rear_center >= 0 )
201 if ( p_sys->i_rear_right >= 0 )
206 for ( i = 0; i < i_nb_samples; ++i )
208 float f_left = p_in[ i * 2 ];
209 float f_right = p_in[ i * 2 + 1 ];
210 float f_rear = ( f_left - f_right ) / i_nb_rear;
212 if ( p_sys->i_center >= 0 )
214 float f_center = f_left + f_right;
215 f_left -= f_center / 2;
216 f_right -= f_center / 2;
218 p_out[ i * i_nb_channels + p_sys->i_center ] = f_center;
221 if ( p_sys->i_left >= 0 )
223 p_out[ i * i_nb_channels + p_sys->i_left ] = f_left;
225 if ( p_sys->i_right >= 0 )
227 p_out[ i * i_nb_channels + p_sys->i_right ] = f_right;
229 if ( p_sys->i_rear_left >= 0 )
231 p_out[ i * i_nb_channels + p_sys->i_rear_left ] = f_rear;
233 if ( p_sys->i_rear_center >= 0 )
235 p_out[ i * i_nb_channels + p_sys->i_rear_center ] = f_rear;
237 if ( p_sys->i_rear_right >= 0 )
239 p_out[ i * i_nb_channels + p_sys->i_rear_right ] = f_rear;