1 /*****************************************************************************
2 * filters.c : audio output filters management
3 *****************************************************************************
4 * Copyright (C) 2002 VideoLAN
5 * $Id: filters.c,v 1.12 2002/10/20 12:23:48 massiot Exp $
7 * Authors: Christophe Massiot <massiot@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., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
22 *****************************************************************************/
24 /*****************************************************************************
26 *****************************************************************************/
27 #include <stdlib.h> /* calloc(), malloc(), free() */
36 #include "audio_output.h"
37 #include "aout_internal.h"
39 /*****************************************************************************
40 * FindFilter: find an audio filter for a specific transformation
41 *****************************************************************************/
42 static aout_filter_t * FindFilter( aout_instance_t * p_aout,
43 const audio_sample_format_t * p_input_format,
44 const audio_sample_format_t * p_output_format )
46 aout_filter_t * p_filter = vlc_object_create( p_aout,
47 sizeof(aout_filter_t) );
49 if ( p_filter == NULL ) return NULL;
50 vlc_object_attach( p_filter, p_aout );
52 memcpy( &p_filter->input, p_input_format, sizeof(audio_sample_format_t) );
53 memcpy( &p_filter->output, p_output_format,
54 sizeof(audio_sample_format_t) );
55 p_filter->p_module = module_Need( p_filter, "audio filter", NULL );
56 if ( p_filter->p_module == NULL )
58 vlc_object_detach( p_filter );
59 vlc_object_destroy( p_filter );
66 /*****************************************************************************
67 * SplitConversion: split a conversion in two parts
68 *****************************************************************************
69 * Returns the number of conversions required by the first part - 0 if only
70 * one conversion was asked.
71 * Beware : p_output_format can be modified during this function if the
72 * developer passed SplitConversion( toto, titi, titi, ... ). That is legal.
73 * SplitConversion( toto, titi, toto, ... ) isn't.
74 *****************************************************************************/
75 static int SplitConversion( aout_instance_t * p_aout,
76 const audio_sample_format_t * p_input_format,
77 const audio_sample_format_t * p_output_format,
78 audio_sample_format_t * p_middle_format )
81 (p_input_format->i_format != p_output_format->i_format);
82 vlc_bool_t b_rate = (p_input_format->i_rate != p_output_format->i_rate);
83 vlc_bool_t b_channels =
84 (p_input_format->i_channels != p_output_format->i_channels);
85 int i_nb_conversions = b_format + b_rate + b_channels;
87 if ( i_nb_conversions <= 1 ) return 0;
89 memcpy( p_middle_format, p_output_format, sizeof(audio_sample_format_t) );
91 if ( i_nb_conversions == 2 )
93 if ( !b_format || !b_channels )
95 p_middle_format->i_rate = p_input_format->i_rate;
100 p_middle_format->i_channels = p_input_format->i_channels;
104 /* i_nb_conversion == 3 */
105 p_middle_format->i_rate = p_input_format->i_rate;
109 /*****************************************************************************
110 * aout_FiltersCreatePipeline: create a filters pipeline to transform a sample
112 *****************************************************************************
113 * TODO : allow the user to add/remove specific filters
114 *****************************************************************************/
115 int aout_FiltersCreatePipeline( aout_instance_t * p_aout,
116 aout_filter_t ** pp_filters,
118 const audio_sample_format_t * p_input_format,
119 const audio_sample_format_t * p_output_format )
121 audio_sample_format_t temp_format;
122 int i_nb_conversions;
124 if ( AOUT_FMTS_IDENTICAL( p_input_format, p_output_format ) )
126 msg_Dbg( p_aout, "no need for any filter" );
131 aout_FormatsPrint( p_aout, "filter(s)", p_input_format, p_output_format );
133 /* Try to find a filter to do the whole conversion. */
134 pp_filters[0] = FindFilter( p_aout, p_input_format, p_output_format );
135 if ( pp_filters[0] != NULL )
137 msg_Dbg( p_aout, "found a filter for the whole conversion" );
142 /* We'll have to split the conversion. We always do the downmixing
143 * before the resampling, because the audio decoder can probably do it
145 i_nb_conversions = SplitConversion( p_aout, p_input_format,
146 p_output_format, &temp_format );
147 if ( !i_nb_conversions )
149 /* There was only one conversion to do, and we already failed. */
150 msg_Err( p_aout, "couldn't find a filter for the conversion" );
154 pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
155 if ( pp_filters[0] == NULL && i_nb_conversions == 2 )
157 /* Try with only one conversion. */
158 SplitConversion( p_aout, p_input_format, &temp_format,
160 pp_filters[0] = FindFilter( p_aout, p_input_format,
163 if ( pp_filters[0] == NULL )
166 "couldn't find a filter for the first part of the conversion" );
170 /* We have the first stage of the conversion. Find a filter for
172 pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
174 if ( pp_filters[1] == NULL )
176 /* Try to split the conversion. */
177 i_nb_conversions = SplitConversion( p_aout,
178 &pp_filters[0]->output,
179 p_output_format, &temp_format );
180 if ( !i_nb_conversions )
182 vlc_object_detach( pp_filters[0] );
183 vlc_object_destroy( pp_filters[0] );
185 "couldn't find a filter for the second part of the conversion" );
187 pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
189 pp_filters[2] = FindFilter( p_aout, &temp_format,
192 if ( pp_filters[1] == NULL || pp_filters[2] == NULL )
194 vlc_object_detach( pp_filters[0] );
195 vlc_object_destroy( pp_filters[0] );
196 if ( pp_filters[1] != NULL )
198 vlc_object_detach( pp_filters[1] );
199 vlc_object_destroy( pp_filters[1] );
201 if ( pp_filters[2] != NULL )
203 vlc_object_detach( pp_filters[2] );
204 vlc_object_destroy( pp_filters[2] );
207 "couldn't find filters for the second part of the conversion" );
216 /* We have enough filters. */
217 msg_Dbg( p_aout, "found %d filters for the whole conversion",
222 /*****************************************************************************
223 * aout_FiltersDestroyPipeline: deallocate a filters pipeline
224 *****************************************************************************/
225 void aout_FiltersDestroyPipeline( aout_instance_t * p_aout,
226 aout_filter_t ** pp_filters,
231 for ( i = 0; i < i_nb_filters; i++ )
233 module_Unneed( pp_filters[i], pp_filters[i]->p_module );
234 vlc_object_detach( pp_filters[i] );
235 vlc_object_destroy( pp_filters[i] );
239 /*****************************************************************************
240 * aout_FiltersHintBuffers: fill in aout_alloc_t structures to optimize
242 *****************************************************************************/
243 void aout_FiltersHintBuffers( aout_instance_t * p_aout,
244 aout_filter_t ** pp_filters,
245 int i_nb_filters, aout_alloc_t * p_first_alloc )
249 for ( i = i_nb_filters - 1; i >= 0; i-- )
251 aout_filter_t * p_filter = pp_filters[i];
253 int i_output_size = p_filter->output.i_bytes_per_frame
254 * p_filter->output.i_rate
255 / p_filter->output.i_frame_length;
256 int i_input_size = p_filter->input.i_bytes_per_frame
257 * p_filter->input.i_rate
258 / p_filter->input.i_frame_length;
260 p_first_alloc->i_bytes_per_sec = __MAX( p_first_alloc->i_bytes_per_sec,
263 if ( p_filter->b_in_place )
265 p_first_alloc->i_bytes_per_sec = __MAX(
266 p_first_alloc->i_bytes_per_sec,
268 p_filter->output_alloc.i_alloc_type = AOUT_ALLOC_NONE;
272 /* We're gonna need a buffer allocation. */
273 memcpy( &p_filter->output_alloc, p_first_alloc,
274 sizeof(aout_alloc_t) );
275 p_first_alloc->i_alloc_type = AOUT_ALLOC_STACK;
276 p_first_alloc->i_bytes_per_sec = i_input_size;
281 /*****************************************************************************
282 * aout_FiltersPlay: play a buffer
283 *****************************************************************************/
284 void aout_FiltersPlay( aout_instance_t * p_aout,
285 aout_filter_t ** pp_filters,
286 int i_nb_filters, aout_buffer_t ** pp_input_buffer )
290 for ( i = 0; i < i_nb_filters; i++ )
292 aout_filter_t * p_filter = pp_filters[i];
293 aout_buffer_t * p_output_buffer;
295 aout_BufferAlloc( &p_filter->output_alloc,
296 (mtime_t)(*pp_input_buffer)->i_nb_samples * 1000000
297 / p_filter->input.i_rate, *pp_input_buffer,
299 if ( p_output_buffer == NULL )
301 msg_Err( p_aout, "out of memory" );
304 /* Please note that p_output_buffer->i_nb_samples & i_nb_bytes
305 * shall be set by the filter plug-in. */
307 p_filter->pf_do_work( p_aout, p_filter, *pp_input_buffer,
310 if ( !p_filter->b_in_place )
312 aout_BufferFree( *pp_input_buffer );
313 *pp_input_buffer = p_output_buffer;