1 /*****************************************************************************
2 * simple.c : simple channel mixer plug-in (only 7/7.1/5/5.1 -> Stereo for now)
3 *****************************************************************************
4 * Copyright (C) 2002 the VideoLAN team
7 * Authors: Gildas Bazin <gbazin@videolan.org>
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., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
22 *****************************************************************************/
24 /*****************************************************************************
26 *****************************************************************************/
27 #include <stdlib.h> /* malloc(), free() */
31 #include "audio_output.h"
32 #include "aout_internal.h"
34 /*****************************************************************************
36 *****************************************************************************/
37 static int Create ( vlc_object_t * );
39 static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
42 /*****************************************************************************
44 *****************************************************************************/
46 set_description( _("audio filter for simple channel mixing") );
47 set_capability( "audio filter", 10 );
48 set_category( CAT_AUDIO );
49 set_subcategory( SUBCAT_AUDIO_MISC );
50 set_callbacks( Create, NULL );
53 /*****************************************************************************
54 * Create: allocate trivial channel mixer
55 *****************************************************************************/
56 static int Create( vlc_object_t *p_this )
58 aout_filter_t * p_filter = (aout_filter_t *)p_this;
60 if ( (p_filter->input.i_physical_channels
61 == p_filter->output.i_physical_channels
62 && p_filter->input.i_original_channels
63 == p_filter->output.i_original_channels)
64 || p_filter->input.i_format != p_filter->output.i_format
65 || p_filter->input.i_rate != p_filter->output.i_rate
66 || p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
71 /* Only conversion to Stereo right now */
72 if( p_filter->output.i_physical_channels !=
73 (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT) ) return -1;
75 /* Only from 7/7.1/5/5.1 */
76 if( (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
77 (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
78 AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) &&
79 (p_filter->input.i_physical_channels & ~AOUT_CHAN_LFE) !=
80 (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER |
81 AOUT_CHAN_MIDDLELEFT | AOUT_CHAN_MIDDLERIGHT |
82 AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT) )
87 p_filter->pf_do_work = DoWork;
88 p_filter->b_in_place = 0;
93 /*****************************************************************************
94 * DoWork: convert a buffer
95 *****************************************************************************/
96 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
97 aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
99 int i_input_nb = aout_FormatNbChannels( &p_filter->input );
100 int i_output_nb = aout_FormatNbChannels( &p_filter->output );
101 float *p_dest = (float *)p_out_buf->p_buffer;
102 float *p_src = (float *)p_in_buf->p_buffer;
105 p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
106 p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes * i_output_nb / i_input_nb;
108 if( p_filter->input.i_physical_channels & AOUT_CHAN_MIDDLELEFT )
109 for( i = p_in_buf->i_nb_samples; i--; )
111 *p_dest = p_src[6] + 0.5 * p_src[0] + p_src[2] / 4 + p_src[4] / 4;
113 *p_dest = p_src[6] + 0.5 * p_src[1] + p_src[3] / 4 + p_src[5] / 4;
118 if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;
121 for( i = p_in_buf->i_nb_samples; i--; )
123 *p_dest = p_src[4] + 0.5 * p_src[0] + 0.33 * p_src[2];
125 *p_dest = p_src[4] + 0.5 * p_src[1] + 0.33 * p_src[3];
130 if( p_filter->input.i_physical_channels & AOUT_CHAN_LFE ) p_src++;