1 /*****************************************************************************
2 * bandlimited.c : band-limited interpolation resampler
3 *****************************************************************************
4 * Copyright (C) 2002, 2006 the VideoLAN team
7 * Authors: Gildas Bazin <gbazin@netcourrier.com>
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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
22 *****************************************************************************/
24 /*****************************************************************************
27 * This implementation of the band-limited interpolationis based on the
29 * http://ccrma-www.stanford.edu/~jos/resample/resample.html
31 * It uses a Kaiser-windowed sinc-function low-pass filter and the width of the
32 * filter is 13 samples.
34 *****************************************************************************/
40 #include <vlc_common.h>
41 #include <vlc_plugin.h>
43 #include <vlc_filter.h>
44 #include <vlc_block.h>
48 #include "bandlimited.h"
50 /*****************************************************************************
52 *****************************************************************************/
55 static int OpenFilter ( vlc_object_t * );
56 static void CloseFilter( vlc_object_t * );
57 static block_t *Resample( filter_t *, block_t * );
60 static void FilterFloatUP( const float Imp[], const float ImpD[], uint16_t Nwing,
61 float *f_in, float *f_out, uint32_t ui_remainder,
62 uint32_t ui_output_rate, int16_t Inc,
65 static void FilterFloatUD( const float Imp[], const float ImpD[], uint16_t Nwing,
66 float *f_in, float *f_out, uint32_t ui_remainder,
67 uint32_t ui_output_rate, uint32_t ui_input_rate,
68 int16_t Inc, int i_nb_channels );
70 /*****************************************************************************
72 *****************************************************************************/
75 int32_t *p_buf; /* this filter introduces a delay */
81 unsigned int i_remainder; /* remainder of previous sample */
87 /*****************************************************************************
89 *****************************************************************************/
91 set_category( CAT_AUDIO )
92 set_subcategory( SUBCAT_AUDIO_MISC )
93 set_description( N_("Audio filter for band-limited interpolation resampling") )
94 set_capability( "audio filter", 20 )
95 set_callbacks( OpenFilter, CloseFilter )
98 /*****************************************************************************
99 * Resample: convert a buffer
100 *****************************************************************************/
101 static block_t *Resample( filter_t * p_filter, block_t * p_in_buf )
103 if( !p_in_buf || !p_in_buf->i_nb_samples )
106 block_Release( p_in_buf );
110 filter_sys_t *p_sys = p_filter->p_sys;
111 unsigned int i_out_rate = p_filter->fmt_out.audio.i_rate;
112 int i_nb_channels = aout_FormatNbChannels( &p_filter->fmt_in.audio );
114 /* Check if we really need to run the resampler */
115 if( i_out_rate == p_filter->fmt_in.audio.i_rate )
117 if( !(p_in_buf->i_flags & BLOCK_FLAG_DISCONTINUITY) &&
120 /* output the whole thing with the samples from last time */
121 p_in_buf = block_Realloc( p_in_buf,
122 p_sys->i_old_wing * p_filter->fmt_in.audio.i_bytes_per_frame,
123 p_in_buf->i_buffer );
126 memcpy( p_in_buf->p_buffer, p_sys->p_buf +
127 i_nb_channels * p_sys->i_old_wing,
129 p_filter->fmt_in.audio.i_bytes_per_frame );
131 p_in_buf->i_nb_samples += p_sys->i_old_wing;
133 p_in_buf->i_pts = date_Get( &p_sys->end_date );
135 date_Increment( &p_sys->end_date,
136 p_in_buf->i_nb_samples ) - p_in_buf->i_pts;
138 p_sys->i_old_wing = 0;
139 p_sys->b_first = true;
143 unsigned i_bytes_per_frame = p_filter->fmt_out.audio.i_channels *
144 p_filter->fmt_out.audio.i_bitspersample / 8;
145 size_t i_out_size = i_bytes_per_frame * ( 1 + ( p_in_buf->i_nb_samples *
146 p_filter->fmt_out.audio.i_rate / p_filter->fmt_in.audio.i_rate) )
147 + p_filter->p_sys->i_buf_size;
148 block_t *p_out_buf = filter_NewAudioBuffer( p_filter, i_out_size );
151 float *p_out = (float *)p_out_buf->p_buffer;
153 if( (p_in_buf->i_flags & BLOCK_FLAG_DISCONTINUITY) || p_sys->b_first )
155 /* Continuity in sound samples has been broken, we'd better reset
157 p_out_buf->i_flags |= BLOCK_FLAG_DISCONTINUITY;
158 p_sys->i_remainder = 0;
159 date_Init( &p_sys->end_date, i_out_rate, 1 );
160 date_Set( &p_sys->end_date, p_in_buf->i_pts );
161 p_sys->d_old_factor = 1;
162 p_sys->i_old_wing = 0;
163 p_sys->b_first = false;
166 size_t i_in_nb = p_in_buf->i_nb_samples;
167 size_t i_in, i_out = 0;
168 double d_factor, d_scale_factor, d_old_scale_factor;
169 size_t i_filter_wing;
172 msg_Err( p_filter, "old rate: %i, old factor: %f, old wing: %i, i_in: %i",
173 p_sys->i_old_rate, p_sys->d_old_factor,
174 p_sys->i_old_wing, i_in_nb );
177 /* Same format in and out... */
178 assert( p_filter->fmt_in.audio.i_bytes_per_frame == i_bytes_per_frame );
180 /* Prepare the source buffer */
181 if( p_sys->i_old_wing )
182 { /* Copy all our samples in p_in_buf */
183 /* Normally, there should be enough room for the old wing in the
184 * buffer head room. Otherwise, we need to copy memory anyway. */
185 p_in_buf = block_Realloc( p_in_buf,
186 p_sys->i_old_wing * 2 * i_bytes_per_frame,
187 p_in_buf->i_buffer );
188 if( unlikely(p_in_buf == NULL) )
190 memcpy( p_in_buf->p_buffer, p_sys->p_buf,
191 p_sys->i_old_wing * 2 * i_bytes_per_frame );
193 i_in_nb += (p_sys->i_old_wing * 2);
194 float *p_in = (float *)p_in_buf->p_buffer;
195 const float *p_in_orig = p_in;
197 /* Make sure the output buffer is reset */
198 memset( p_out, 0, p_out_buf->i_buffer );
200 /* Calculate the new length of the filter wing */
201 d_factor = (double)i_out_rate / p_filter->fmt_in.audio.i_rate;
202 i_filter_wing = ((SMALL_FILTER_NMULT+1)/2.0) * __MAX(1.0,1.0/d_factor) + 1;
204 /* Account for increased filter gain when using factors less than 1 */
205 d_old_scale_factor = SMALL_FILTER_SCALE *
206 p_sys->d_old_factor + 0.5;
207 d_scale_factor = SMALL_FILTER_SCALE * d_factor + 0.5;
209 /* Apply the old rate until we have enough samples for the new one */
210 i_in = p_sys->i_old_wing;
211 p_in += p_sys->i_old_wing * i_nb_channels;
212 for( ; i_in < i_filter_wing &&
213 (i_in + p_sys->i_old_wing) < i_in_nb; i_in++ )
215 if( p_sys->d_old_factor == 1 )
217 /* Just copy the samples */
218 memcpy( p_out, p_in, i_bytes_per_frame );
219 p_in += i_nb_channels;
220 p_out += i_nb_channels;
225 while( p_sys->i_remainder < p_filter->fmt_out.audio.i_rate )
227 if( p_out_buf->i_buffer/i_bytes_per_frame <= i_out )
230 if( p_sys->d_old_factor >= 1 )
232 /* FilterFloatUP() is faster if we can use it */
234 /* Perform left-wing inner product */
235 FilterFloatUP( SMALL_FILTER_FLOAT_IMP, SMALL_FILTER_FLOAT_IMPD,
236 SMALL_FILTER_NWING, p_in, p_out,
238 p_filter->fmt_out.audio.i_rate,
240 /* Perform right-wing inner product */
241 FilterFloatUP( SMALL_FILTER_FLOAT_IMP, SMALL_FILTER_FLOAT_IMPD,
242 SMALL_FILTER_NWING, p_in + i_nb_channels, p_out,
243 p_filter->fmt_out.audio.i_rate -
245 p_filter->fmt_out.audio.i_rate,
249 /* Normalize for unity filter gain */
250 for( i = 0; i < i_nb_channels; i++ )
252 *(p_out+i) *= d_old_scale_factor;
258 /* Perform left-wing inner product */
259 FilterFloatUD( SMALL_FILTER_FLOAT_IMP, SMALL_FILTER_FLOAT_IMPD,
260 SMALL_FILTER_NWING, p_in, p_out,
262 p_filter->fmt_out.audio.i_rate, p_filter->fmt_in.audio.i_rate,
264 /* Perform right-wing inner product */
265 FilterFloatUD( SMALL_FILTER_FLOAT_IMP, SMALL_FILTER_FLOAT_IMPD,
266 SMALL_FILTER_NWING, p_in + i_nb_channels, p_out,
267 p_filter->fmt_out.audio.i_rate -
269 p_filter->fmt_out.audio.i_rate, p_filter->fmt_in.audio.i_rate,
273 p_out += i_nb_channels;
276 p_sys->i_remainder += p_filter->fmt_in.audio.i_rate;
279 p_in += i_nb_channels;
280 p_sys->i_remainder -= p_filter->fmt_out.audio.i_rate;
283 /* Apply the new rate for the rest of the samples */
284 if( i_in < i_in_nb - i_filter_wing )
286 p_sys->d_old_factor = d_factor;
287 p_sys->i_old_wing = i_filter_wing;
289 for( ; i_in < i_in_nb - i_filter_wing; i_in++ )
291 while( p_sys->i_remainder < p_filter->fmt_out.audio.i_rate )
293 if( p_out_buf->i_buffer/i_bytes_per_frame <= i_out )
296 assert( i_out < p_out_buf->i_buffer/i_bytes_per_frame );
299 /* FilterFloatUP() is faster if we can use it */
301 /* Perform left-wing inner product */
302 FilterFloatUP( SMALL_FILTER_FLOAT_IMP, SMALL_FILTER_FLOAT_IMPD,
303 SMALL_FILTER_NWING, p_in, p_out,
305 p_filter->fmt_out.audio.i_rate,
308 /* Perform right-wing inner product */
309 FilterFloatUP( SMALL_FILTER_FLOAT_IMP, SMALL_FILTER_FLOAT_IMPD,
310 SMALL_FILTER_NWING, p_in + i_nb_channels, p_out,
311 p_filter->fmt_out.audio.i_rate -
313 p_filter->fmt_out.audio.i_rate,
317 /* Normalize for unity filter gain */
318 for( int i = 0; i < i_nb_channels; i++ )
320 *(p_out+i) *= d_old_scale_factor;
326 /* Perform left-wing inner product */
327 FilterFloatUD( SMALL_FILTER_FLOAT_IMP, SMALL_FILTER_FLOAT_IMPD,
328 SMALL_FILTER_NWING, p_in, p_out,
330 p_filter->fmt_out.audio.i_rate, p_filter->fmt_in.audio.i_rate,
332 /* Perform right-wing inner product */
333 FilterFloatUD( SMALL_FILTER_FLOAT_IMP, SMALL_FILTER_FLOAT_IMPD,
334 SMALL_FILTER_NWING, p_in + i_nb_channels, p_out,
335 p_filter->fmt_out.audio.i_rate -
337 p_filter->fmt_out.audio.i_rate, p_filter->fmt_in.audio.i_rate,
341 p_out += i_nb_channels;
344 p_sys->i_remainder += p_filter->fmt_in.audio.i_rate;
347 p_in += i_nb_channels;
348 p_sys->i_remainder -= p_filter->fmt_out.audio.i_rate;
351 /* Finalize aout buffer */
352 p_out_buf->i_nb_samples = i_out;
353 p_out_buf->i_pts = date_Get( &p_sys->end_date );
354 p_out_buf->i_length = date_Increment( &p_sys->end_date,
355 p_out_buf->i_nb_samples ) - p_out_buf->i_pts;
357 p_out_buf->i_buffer = p_out_buf->i_nb_samples *
358 i_nb_channels * sizeof(int32_t);
360 /* Buffer i_filter_wing * 2 samples for next time */
361 if( p_sys->i_old_wing )
363 size_t newsize = p_sys->i_old_wing * 2 * i_bytes_per_frame;
364 if( newsize > p_sys->i_buf_size )
366 free( p_sys->p_buf );
367 p_sys->p_buf = malloc( newsize );
368 if( p_sys->p_buf != NULL )
369 p_sys->i_buf_size = newsize;
372 p_sys->i_buf_size = p_sys->i_old_wing = 0; /* oops! */
376 memcpy( p_sys->p_buf,
377 p_in_orig + (i_in_nb - 2 * p_sys->i_old_wing) *
378 i_nb_channels, (2 * p_sys->i_old_wing) *
379 p_filter->fmt_in.audio.i_bytes_per_frame );
383 msg_Err( p_filter, "p_out size: %i, nb bytes out: %i", p_out_buf->i_buffer,
384 i_out * p_filter->fmt_in.audio.i_bytes_per_frame );
390 /*****************************************************************************
392 *****************************************************************************/
393 static int OpenFilter( vlc_object_t *p_this )
395 filter_t *p_filter = (filter_t *)p_this;
397 unsigned int i_out_rate = p_filter->fmt_out.audio.i_rate;
399 if ( p_filter->fmt_in.audio.i_rate == p_filter->fmt_out.audio.i_rate
400 || p_filter->fmt_in.audio.i_format != p_filter->fmt_out.audio.i_format
401 || p_filter->fmt_in.audio.i_physical_channels
402 != p_filter->fmt_out.audio.i_physical_channels
403 || p_filter->fmt_in.audio.i_original_channels
404 != p_filter->fmt_out.audio.i_original_channels
405 || p_filter->fmt_in.audio.i_format != VLC_CODEC_FL32 )
410 #if !defined( SYS_DARWIN )
411 if( !var_InheritInteger( p_this, "hq-resampling" ) )
417 /* Allocate the memory needed to store the module's structure */
418 p_filter->p_sys = p_sys = malloc( sizeof(struct filter_sys_t) );
423 p_sys->i_buf_size = 0;
425 p_sys->i_old_wing = 0;
426 p_sys->b_first = true;
427 p_filter->pf_audio_filter = Resample;
429 msg_Dbg( p_this, "%4.4s/%iKHz/%i->%4.4s/%iKHz/%i",
430 (char *)&p_filter->fmt_in.i_codec,
431 p_filter->fmt_in.audio.i_rate,
432 p_filter->fmt_in.audio.i_channels,
433 (char *)&p_filter->fmt_out.i_codec,
434 p_filter->fmt_out.audio.i_rate,
435 p_filter->fmt_out.audio.i_channels);
437 p_filter->fmt_out = p_filter->fmt_in;
438 p_filter->fmt_out.audio.i_rate = i_out_rate;
443 /*****************************************************************************
444 * CloseFilter : deallocate data structures
445 *****************************************************************************/
446 static void CloseFilter( vlc_object_t *p_this )
448 filter_t *p_filter = (filter_t *)p_this;
449 free( p_filter->p_sys->p_buf );
450 free( p_filter->p_sys );
453 void FilterFloatUP( const float Imp[], const float ImpD[], uint16_t Nwing, float *p_in,
454 float *p_out, uint32_t ui_remainder,
455 uint32_t ui_output_rate, int16_t Inc, int i_nb_channels )
457 const float *Hp, *Hdp, *End;
459 uint32_t ui_linear_remainder;
462 Hp = &Imp[(ui_remainder<<Nhc)/ui_output_rate];
463 Hdp = &ImpD[(ui_remainder<<Nhc)/ui_output_rate];
467 ui_linear_remainder = (ui_remainder<<Nhc) -
468 (ui_remainder<<Nhc)/ui_output_rate*ui_output_rate;
470 if (Inc == 1) /* If doing right wing... */
471 { /* ...drop extra coeff, so when Ph is */
472 End--; /* 0.5, we don't do too many mult's */
473 if (ui_remainder == 0) /* If the phase is zero... */
474 { /* ...then we've already skipped the */
475 Hp += Npc; /* first sample, so we must also */
476 Hdp += Npc; /* skip ahead in Imp[] and ImpD[] */
481 t = *Hp; /* Get filter coeff */
482 /* t is now interp'd filter coeff */
483 t += *Hdp * ui_linear_remainder / ui_output_rate / Npc;
484 for( i = 0; i < i_nb_channels; i++ )
487 temp *= *(p_in+i); /* Mult coeff by input sample */
488 *(p_out+i) += temp; /* The filter output */
490 Hdp += Npc; /* Filter coeff differences step */
491 Hp += Npc; /* Filter coeff step */
492 p_in += (Inc * i_nb_channels); /* Input signal step */
496 void FilterFloatUD( const float Imp[], const float ImpD[], uint16_t Nwing, float *p_in,
497 float *p_out, uint32_t ui_remainder,
498 uint32_t ui_output_rate, uint32_t ui_input_rate,
499 int16_t Inc, int i_nb_channels )
501 const float *Hp, *Hdp, *End;
503 uint32_t ui_linear_remainder;
504 int i, ui_counter = 0;
506 Hp = Imp + (ui_remainder<<Nhc) / ui_input_rate;
507 Hdp = ImpD + (ui_remainder<<Nhc) / ui_input_rate;
511 if (Inc == 1) /* If doing right wing... */
512 { /* ...drop extra coeff, so when Ph is */
513 End--; /* 0.5, we don't do too many mult's */
514 if (ui_remainder == 0) /* If the phase is zero... */
515 { /* ...then we've already skipped the */
516 Hp = Imp + /* first sample, so we must also */
517 (ui_output_rate << Nhc) / ui_input_rate;
518 Hdp = ImpD + /* skip ahead in Imp[] and ImpD[] */
519 (ui_output_rate << Nhc) / ui_input_rate;
525 t = *Hp; /* Get filter coeff */
526 /* t is now interp'd filter coeff */
527 ui_linear_remainder =
528 ((ui_output_rate * ui_counter + ui_remainder)<< Nhc) -
529 ((ui_output_rate * ui_counter + ui_remainder)<< Nhc) /
530 ui_input_rate * ui_input_rate;
531 t += *Hdp * ui_linear_remainder / ui_input_rate / Npc;
532 for( i = 0; i < i_nb_channels; i++ )
535 temp *= *(p_in+i); /* Mult coeff by input sample */
536 *(p_out+i) += temp; /* The filter output */
541 /* Filter coeff step */
542 Hp = Imp + ((ui_output_rate * ui_counter + ui_remainder)<< Nhc)
544 /* Filter coeff differences step */
545 Hdp = ImpD + ((ui_output_rate * ui_counter + ui_remainder)<< Nhc)
548 p_in += (Inc * i_nb_channels); /* Input signal step */