1 /*****************************************************************************
2 * filters.c : audio output filters management
3 *****************************************************************************
4 * Copyright (C) 2002 VideoLAN
5 * $Id: filters.c,v 1.15 2002/12/06 10:10:39 sam 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 );
63 p_filter->b_reinit = VLC_TRUE;
68 /*****************************************************************************
69 * SplitConversion: split a conversion in two parts
70 *****************************************************************************
71 * Returns the number of conversions required by the first part - 0 if only
72 * one conversion was asked.
73 * Beware : p_output_format can be modified during this function if the
74 * developer passed SplitConversion( toto, titi, titi, ... ). That is legal.
75 * SplitConversion( toto, titi, toto, ... ) isn't.
76 *****************************************************************************/
77 static int SplitConversion( const audio_sample_format_t * p_input_format,
78 const audio_sample_format_t * p_output_format,
79 audio_sample_format_t * p_middle_format )
82 (p_input_format->i_format != p_output_format->i_format);
83 vlc_bool_t b_rate = (p_input_format->i_rate != p_output_format->i_rate);
84 vlc_bool_t b_channels =
85 (p_input_format->i_physical_channels
86 != p_output_format->i_physical_channels)
87 || (p_input_format->i_original_channels
88 != p_output_format->i_original_channels);
89 int i_nb_conversions = b_format + b_rate + b_channels;
91 if ( i_nb_conversions <= 1 ) return 0;
93 memcpy( p_middle_format, p_output_format, sizeof(audio_sample_format_t) );
95 if ( i_nb_conversions == 2 )
97 if ( !b_format || !b_channels )
99 p_middle_format->i_rate = p_input_format->i_rate;
104 p_middle_format->i_physical_channels
105 = p_input_format->i_physical_channels;
106 p_middle_format->i_original_channels
107 = p_input_format->i_original_channels;
111 /* i_nb_conversion == 3 */
112 p_middle_format->i_rate = p_input_format->i_rate;
116 /*****************************************************************************
117 * aout_FiltersCreatePipeline: create a filters pipeline to transform a sample
119 *****************************************************************************
120 * TODO : allow the user to add/remove specific filters
121 *****************************************************************************/
122 int aout_FiltersCreatePipeline( aout_instance_t * p_aout,
123 aout_filter_t ** pp_filters,
125 const audio_sample_format_t * p_input_format,
126 const audio_sample_format_t * p_output_format )
128 audio_sample_format_t temp_format;
129 int i_nb_conversions;
131 if ( AOUT_FMTS_IDENTICAL( p_input_format, p_output_format ) )
133 msg_Dbg( p_aout, "no need for any filter" );
138 aout_FormatsPrint( p_aout, "filter(s)", p_input_format, p_output_format );
140 /* Try to find a filter to do the whole conversion. */
141 pp_filters[0] = FindFilter( p_aout, p_input_format, p_output_format );
142 if ( pp_filters[0] != NULL )
144 msg_Dbg( p_aout, "found a filter for the whole conversion" );
149 /* We'll have to split the conversion. We always do the downmixing
150 * before the resampling, because the audio decoder can probably do it
152 i_nb_conversions = SplitConversion( p_input_format,
153 p_output_format, &temp_format );
154 if ( !i_nb_conversions )
156 /* There was only one conversion to do, and we already failed. */
157 msg_Err( p_aout, "couldn't find a filter for the conversion" );
161 pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
162 if ( pp_filters[0] == NULL && i_nb_conversions == 2 )
164 /* Try with only one conversion. */
165 SplitConversion( p_input_format, &temp_format, &temp_format );
166 pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
168 if ( pp_filters[0] == NULL )
171 "couldn't find a filter for the first part of the conversion" );
175 /* We have the first stage of the conversion. Find a filter for
177 pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
179 if ( pp_filters[1] == NULL )
181 /* Try to split the conversion. */
182 i_nb_conversions = SplitConversion( &pp_filters[0]->output,
183 p_output_format, &temp_format );
184 if ( !i_nb_conversions )
186 vlc_object_detach( pp_filters[0] );
187 vlc_object_destroy( pp_filters[0] );
189 "couldn't find a filter for the second part of the conversion" );
191 pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
193 pp_filters[2] = FindFilter( p_aout, &temp_format,
196 if ( pp_filters[1] == NULL || pp_filters[2] == NULL )
198 vlc_object_detach( pp_filters[0] );
199 vlc_object_destroy( pp_filters[0] );
200 if ( pp_filters[1] != NULL )
202 vlc_object_detach( pp_filters[1] );
203 vlc_object_destroy( pp_filters[1] );
205 if ( pp_filters[2] != NULL )
207 vlc_object_detach( pp_filters[2] );
208 vlc_object_destroy( pp_filters[2] );
211 "couldn't find filters for the second part of the conversion" );
220 /* We have enough filters. */
221 msg_Dbg( p_aout, "found %d filters for the whole conversion",
226 /*****************************************************************************
227 * aout_FiltersDestroyPipeline: deallocate a filters pipeline
228 *****************************************************************************/
229 void aout_FiltersDestroyPipeline( aout_instance_t * p_aout,
230 aout_filter_t ** pp_filters,
235 for ( i = 0; i < i_nb_filters; i++ )
237 module_Unneed( pp_filters[i], pp_filters[i]->p_module );
238 vlc_object_detach( pp_filters[i] );
239 vlc_object_destroy( pp_filters[i] );
243 /*****************************************************************************
244 * aout_FiltersHintBuffers: fill in aout_alloc_t structures to optimize
246 *****************************************************************************/
247 void aout_FiltersHintBuffers( aout_instance_t * p_aout,
248 aout_filter_t ** pp_filters,
249 int i_nb_filters, aout_alloc_t * p_first_alloc )
253 (void)p_aout; /* unused */
255 for ( i = i_nb_filters - 1; i >= 0; i-- )
257 aout_filter_t * p_filter = pp_filters[i];
259 int i_output_size = p_filter->output.i_bytes_per_frame
260 * p_filter->output.i_rate
261 / p_filter->output.i_frame_length;
262 int i_input_size = p_filter->input.i_bytes_per_frame
263 * p_filter->input.i_rate
264 / p_filter->input.i_frame_length;
266 p_first_alloc->i_bytes_per_sec = __MAX( p_first_alloc->i_bytes_per_sec,
269 if ( p_filter->b_in_place )
271 p_first_alloc->i_bytes_per_sec = __MAX(
272 p_first_alloc->i_bytes_per_sec,
274 p_filter->output_alloc.i_alloc_type = AOUT_ALLOC_NONE;
278 /* We're gonna need a buffer allocation. */
279 memcpy( &p_filter->output_alloc, p_first_alloc,
280 sizeof(aout_alloc_t) );
281 p_first_alloc->i_alloc_type = AOUT_ALLOC_STACK;
282 p_first_alloc->i_bytes_per_sec = i_input_size;
287 /*****************************************************************************
288 * aout_FiltersPlay: play a buffer
289 *****************************************************************************/
290 void aout_FiltersPlay( aout_instance_t * p_aout,
291 aout_filter_t ** pp_filters,
292 int i_nb_filters, aout_buffer_t ** pp_input_buffer )
296 for ( i = 0; i < i_nb_filters; i++ )
298 aout_filter_t * p_filter = pp_filters[i];
299 aout_buffer_t * p_output_buffer;
301 /* We need this because resamplers can produce more samples than
302 (i_in_nb * p_filter->output.i_rate / p_filter->input.i_rate) */
303 int i_compensate_rounding = 2 * p_filter->input.i_rate
304 / p_filter->output.i_rate;
306 aout_BufferAlloc( &p_filter->output_alloc,
307 ((mtime_t)(*pp_input_buffer)->i_nb_samples + i_compensate_rounding)
308 * 1000000 / p_filter->input.i_rate,
309 *pp_input_buffer, p_output_buffer );
310 if ( p_output_buffer == NULL )
312 msg_Err( p_aout, "out of memory" );
315 /* Please note that p_output_buffer->i_nb_samples & i_nb_bytes
316 * shall be set by the filter plug-in. */
318 p_filter->pf_do_work( p_aout, p_filter, *pp_input_buffer,
321 if ( !p_filter->b_in_place )
323 aout_BufferFree( *pp_input_buffer );
324 *pp_input_buffer = p_output_buffer;