1 /*****************************************************************************
2 * filters.c : audio output filters management
3 *****************************************************************************
4 * Copyright (C) 2002-2004 VideoLAN
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, 0 );
56 if ( p_filter->p_module == NULL )
58 vlc_object_detach( p_filter );
59 vlc_object_destroy( p_filter );
63 p_filter->b_continuity = VLC_FALSE;
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;
100 aout_FormatPrepare( p_middle_format );
105 p_middle_format->i_physical_channels
106 = p_input_format->i_physical_channels;
107 p_middle_format->i_original_channels
108 = p_input_format->i_original_channels;
109 aout_FormatPrepare( p_middle_format );
113 /* i_nb_conversion == 3 */
114 p_middle_format->i_rate = p_input_format->i_rate;
115 aout_FormatPrepare( p_middle_format );
119 /*****************************************************************************
120 * aout_FiltersCreatePipeline: create a filters pipeline to transform a sample
122 *****************************************************************************
123 * TODO : allow the user to add/remove specific filters
124 *****************************************************************************/
125 int aout_FiltersCreatePipeline( aout_instance_t * p_aout,
126 aout_filter_t ** pp_filters,
128 const audio_sample_format_t * p_input_format,
129 const audio_sample_format_t * p_output_format )
131 audio_sample_format_t temp_format;
132 int i_nb_conversions;
134 if ( AOUT_FMTS_IDENTICAL( p_input_format, p_output_format ) )
136 msg_Dbg( p_aout, "no need for any filter" );
141 aout_FormatsPrint( p_aout, "filter(s)", p_input_format, p_output_format );
143 /* Try to find a filter to do the whole conversion. */
144 pp_filters[0] = FindFilter( p_aout, p_input_format, p_output_format );
145 if ( pp_filters[0] != NULL )
147 msg_Dbg( p_aout, "found a filter for the whole conversion" );
152 /* We'll have to split the conversion. We always do the downmixing
153 * before the resampling, because the audio decoder can probably do it
155 i_nb_conversions = SplitConversion( p_input_format,
156 p_output_format, &temp_format );
157 if ( !i_nb_conversions )
159 /* There was only one conversion to do, and we already failed. */
160 msg_Err( p_aout, "couldn't find a filter for the conversion" );
164 pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
165 if ( pp_filters[0] == NULL && i_nb_conversions == 2 )
167 /* Try with only one conversion. */
168 SplitConversion( p_input_format, &temp_format, &temp_format );
169 pp_filters[0] = FindFilter( p_aout, p_input_format, &temp_format );
171 if ( pp_filters[0] == NULL )
174 "couldn't find a filter for the first part of the conversion" );
178 /* We have the first stage of the conversion. Find a filter for
180 pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
182 if ( pp_filters[1] == NULL )
184 /* Try to split the conversion. */
185 i_nb_conversions = SplitConversion( &pp_filters[0]->output,
186 p_output_format, &temp_format );
187 if ( !i_nb_conversions )
189 vlc_object_detach( pp_filters[0] );
190 vlc_object_destroy( pp_filters[0] );
192 "couldn't find a filter for the second part of the conversion" );
194 pp_filters[1] = FindFilter( p_aout, &pp_filters[0]->output,
196 pp_filters[2] = FindFilter( p_aout, &temp_format,
199 if ( pp_filters[1] == NULL || pp_filters[2] == NULL )
201 vlc_object_detach( pp_filters[0] );
202 vlc_object_destroy( pp_filters[0] );
203 if ( pp_filters[1] != NULL )
205 vlc_object_detach( pp_filters[1] );
206 vlc_object_destroy( pp_filters[1] );
208 if ( pp_filters[2] != NULL )
210 vlc_object_detach( pp_filters[2] );
211 vlc_object_destroy( pp_filters[2] );
214 "couldn't find filters for the second part of the conversion" );
223 /* We have enough filters. */
224 msg_Dbg( p_aout, "found %d filters for the whole conversion",
229 /*****************************************************************************
230 * aout_FiltersDestroyPipeline: deallocate a filters pipeline
231 *****************************************************************************/
232 void aout_FiltersDestroyPipeline( aout_instance_t * p_aout,
233 aout_filter_t ** pp_filters,
238 for ( i = 0; i < i_nb_filters; i++ )
240 module_Unneed( pp_filters[i], pp_filters[i]->p_module );
241 vlc_object_detach( pp_filters[i] );
242 vlc_object_destroy( pp_filters[i] );
246 /*****************************************************************************
247 * aout_FiltersHintBuffers: fill in aout_alloc_t structures to optimize
249 *****************************************************************************/
250 void aout_FiltersHintBuffers( aout_instance_t * p_aout,
251 aout_filter_t ** pp_filters,
252 int i_nb_filters, aout_alloc_t * p_first_alloc )
256 (void)p_aout; /* unused */
258 for ( i = i_nb_filters - 1; i >= 0; i-- )
260 aout_filter_t * p_filter = pp_filters[i];
262 int i_output_size = p_filter->output.i_bytes_per_frame
263 * p_filter->output.i_rate
264 / p_filter->output.i_frame_length;
265 int i_input_size = p_filter->input.i_bytes_per_frame
266 * p_filter->input.i_rate
267 / p_filter->input.i_frame_length;
269 p_first_alloc->i_bytes_per_sec = __MAX( p_first_alloc->i_bytes_per_sec,
272 if ( p_filter->b_in_place )
274 p_first_alloc->i_bytes_per_sec = __MAX(
275 p_first_alloc->i_bytes_per_sec,
277 p_filter->output_alloc.i_alloc_type = AOUT_ALLOC_NONE;
281 /* We're gonna need a buffer allocation. */
282 memcpy( &p_filter->output_alloc, p_first_alloc,
283 sizeof(aout_alloc_t) );
284 p_first_alloc->i_alloc_type = AOUT_ALLOC_STACK;
285 p_first_alloc->i_bytes_per_sec = i_input_size;
290 /*****************************************************************************
291 * aout_FiltersPlay: play a buffer
292 *****************************************************************************/
293 void aout_FiltersPlay( aout_instance_t * p_aout,
294 aout_filter_t ** pp_filters,
295 int i_nb_filters, aout_buffer_t ** pp_input_buffer )
299 for ( i = 0; i < i_nb_filters; i++ )
301 aout_filter_t * p_filter = pp_filters[i];
302 aout_buffer_t * p_output_buffer;
304 /* Resamplers can produce slightly more samples than (i_in_nb *
305 * p_filter->output.i_rate / p_filter->input.i_rate) so we need
306 * slightly bigger buffers. */
307 aout_BufferAlloc( &p_filter->output_alloc,
308 ((mtime_t)(*pp_input_buffer)->i_nb_samples + 2)
309 * 1000000 / p_filter->input.i_rate,
310 *pp_input_buffer, p_output_buffer );
311 if ( p_output_buffer == NULL )
313 msg_Err( p_aout, "out of memory" );
316 /* Please note that p_output_buffer->i_nb_samples & i_nb_bytes
317 * shall be set by the filter plug-in. */
319 p_filter->pf_do_work( p_aout, p_filter, *pp_input_buffer,
322 if ( !p_filter->b_in_place )
324 aout_BufferFree( *pp_input_buffer );
325 *pp_input_buffer = p_output_buffer;