1 /*****************************************************************************
2 * filters.c : audio output filters management
3 *****************************************************************************
4 * Copyright (C) 2002 VideoLAN
5 * $Id: filters.c,v 1.8 2002/08/30 22:22:24 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,
79 vlc_bool_t b_format_first,
80 vlc_bool_t b_rate_first )
83 (p_input_format->i_format != p_output_format->i_format);
84 vlc_bool_t b_rate = (p_input_format->i_rate != p_output_format->i_rate);
85 vlc_bool_t b_channels =
86 (p_input_format->i_channels != p_output_format->i_channels);
87 int i_nb_conversions = b_format + b_rate + b_channels;
89 if ( i_nb_conversions <= 1 ) return 0;
91 memcpy( p_middle_format, p_output_format, sizeof(audio_sample_format_t) );
93 if ( i_nb_conversions == 2 )
99 p_middle_format->i_channels = p_input_format->i_channels;
103 p_middle_format->i_rate = p_input_format->i_rate;
110 if ( b_format_first )
112 p_middle_format->i_channels = p_input_format->i_channels;
116 p_middle_format->i_format = p_input_format->i_format;
122 if ( b_format_first )
124 p_middle_format->i_rate = p_input_format->i_rate;
128 p_middle_format->i_format = p_input_format->i_format;
133 /* i_nb_conversion == 3 */
134 if ( !b_format_first )
136 p_middle_format->i_format = p_input_format->i_format;
138 else if ( !b_rate_first )
140 p_middle_format->i_channels = p_input_format->i_channels;
144 p_middle_format->i_rate = p_input_format->i_rate;
150 /*****************************************************************************
151 * aout_FiltersCreatePipeline: create a filters pipeline to transform a sample
153 *****************************************************************************
154 * TODO : allow the user to add/remove specific filters
155 *****************************************************************************/
156 int aout_FiltersCreatePipeline( aout_instance_t * p_aout,
157 aout_filter_t ** pp_filters,
159 const audio_sample_format_t * p_input_format,
160 const audio_sample_format_t * p_output_format )
162 audio_sample_format_t temp_format;
163 vlc_bool_t b_format_first, b_rate_first;
165 if ( AOUT_FMTS_IDENTICAL( p_input_format, p_output_format ) )
167 msg_Dbg( p_aout, "no need for any filter" );
172 msg_Dbg( p_aout, "filter(s) format=%d->%d rate=%d->%d channels=%d->%d",
173 p_input_format->i_format, p_output_format->i_format,
174 p_input_format->i_rate, p_output_format->i_rate,
175 p_input_format->i_channels, p_output_format->i_channels );
177 /* Try to find a filter to do the whole conversion. */
178 pp_filters[0] = FindFilter( p_aout, p_input_format, p_output_format );
179 if ( pp_filters[0] != NULL )
181 msg_Dbg( p_aout, "found a filter for the whole conversion" );
186 /* We'll have to split the conversion. We always do the downmixing
187 * before the resampling, and the upmixing after the resampling (to
188 * maximize the resampling efficiency). */
189 b_rate_first = (p_input_format->i_channels < p_output_format->i_channels);
191 for ( b_format_first = 1; b_format_first >= 0; b_format_first-- )
193 int i_nb_conversions = SplitConversion( p_aout, p_input_format,
194 p_output_format, &temp_format,
195 b_format_first, b_rate_first );
196 if ( !i_nb_conversions )
198 /* There was only one conversion to do, and we already failed. */
199 msg_Err( p_aout, "couldn't find a filter for the conversion" );
203 pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
204 if ( pp_filters[0] == NULL && i_nb_conversions == 2 )
206 /* Try with only one conversion. */
207 SplitConversion( p_aout, p_input_format, &temp_format,
208 &temp_format, b_format_first, b_rate_first );
209 pp_filters[0] = FindFilter( p_aout, p_input_format,
212 if ( pp_filters[0] == NULL )
214 /* Retry with b_format_first = 0. */
218 /* We have the first stage of the conversion. Find a filter for
220 pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
222 if ( pp_filters[1] == NULL )
224 /* Try to split the conversion. */
225 i_nb_conversions = SplitConversion( p_aout,
226 &pp_filters[0]->output,
227 p_output_format, &temp_format,
228 b_format_first, b_rate_first );
229 if ( !i_nb_conversions )
231 vlc_object_detach( pp_filters[0] );
232 vlc_object_destroy( pp_filters[0] );
235 pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
237 pp_filters[2] = FindFilter( p_aout, &temp_format,
240 if ( pp_filters[1] == NULL || pp_filters[2] == NULL )
242 vlc_object_detach( pp_filters[0] );
243 vlc_object_destroy( pp_filters[0] );
244 if ( pp_filters[1] != NULL )
246 vlc_object_detach( pp_filters[1] );
247 vlc_object_destroy( pp_filters[1] );
249 if ( pp_filters[2] != NULL )
251 vlc_object_detach( pp_filters[2] );
252 vlc_object_destroy( pp_filters[2] );
263 /* We have enough filters. */
264 msg_Dbg( p_aout, "found %d filters for the whole conversion",
269 msg_Err( p_aout, "couldn't find filters for the conversion" );
273 /*****************************************************************************
274 * aout_FiltersDestroyPipeline: deallocate a filters pipeline
275 *****************************************************************************/
276 void aout_FiltersDestroyPipeline( aout_instance_t * p_aout,
277 aout_filter_t ** pp_filters,
282 for ( i = 0; i < i_nb_filters; i++ )
284 module_Unneed( pp_filters[i], pp_filters[i]->p_module );
285 vlc_object_detach( pp_filters[i] );
286 vlc_object_destroy( pp_filters[i] );
290 /*****************************************************************************
291 * aout_FiltersHintBuffers: fill in aout_alloc_t structures to optimize
293 *****************************************************************************/
294 void aout_FiltersHintBuffers( aout_instance_t * p_aout,
295 aout_filter_t ** pp_filters,
296 int i_nb_filters, aout_alloc_t * p_first_alloc )
300 for ( i = i_nb_filters - 1; i >= 0; i-- )
302 aout_filter_t * p_filter = pp_filters[i];
304 int i_output_size = p_filter->output.i_bytes_per_frame
305 * p_filter->output.i_rate
306 / p_filter->output.i_frame_length;
307 int i_input_size = p_filter->input.i_bytes_per_frame
308 * p_filter->input.i_rate
309 / p_filter->input.i_frame_length;
311 p_first_alloc->i_bytes_per_sec = __MAX( p_first_alloc->i_bytes_per_sec,
314 if ( p_filter->b_in_place )
316 p_first_alloc->i_bytes_per_sec = __MAX(
317 p_first_alloc->i_bytes_per_sec,
319 p_filter->output_alloc.i_alloc_type = AOUT_ALLOC_NONE;
323 /* We're gonna need a buffer allocation. */
324 memcpy( &p_filter->output_alloc, p_first_alloc,
325 sizeof(aout_alloc_t) );
326 p_first_alloc->i_alloc_type = AOUT_ALLOC_STACK;
327 p_first_alloc->i_bytes_per_sec = i_input_size;
332 /*****************************************************************************
333 * aout_FiltersPlay: play a buffer
334 *****************************************************************************/
335 void aout_FiltersPlay( aout_instance_t * p_aout,
336 aout_filter_t ** pp_filters,
337 int i_nb_filters, aout_buffer_t ** pp_input_buffer )
341 for ( i = 0; i < i_nb_filters; i++ )
343 aout_filter_t * p_filter = pp_filters[i];
344 aout_buffer_t * p_output_buffer;
346 aout_BufferAlloc( &p_filter->output_alloc,
347 (mtime_t)(*pp_input_buffer)->i_nb_samples * 1000000
348 / p_filter->input.i_rate, *pp_input_buffer,
350 if ( p_output_buffer == NULL )
352 msg_Err( p_aout, "out of memory" );
355 /* Please note that p_output_buffer->i_nb_samples & i_nb_bytes
356 * shall be set by the filter plug-in. */
358 p_filter->pf_do_work( p_aout, p_filter, *pp_input_buffer,
361 if ( !p_filter->b_in_place )
363 aout_BufferFree( *pp_input_buffer );
364 *pp_input_buffer = p_output_buffer;