git.sesse.net Git - vlc/blob - modules/audio_filter/resampler/linear.c

   1 /*****************************************************************************
   2  * linear.c : linear interpolation resampler
   3  *****************************************************************************
   4  * Copyright (C) 2002, 2006 the VideoLAN team
   5  * $Id$
   6  *
   7  * Authors: Gildas Bazin <gbazin@netcourrier.com>
   8  *          Sigmund Augdal Helberg <dnumgis@videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28
  29 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <vlc_common.h>
  34 #include <vlc_plugin.h>
  35 #include <vlc_aout.h>
  36 #include <vlc_filter.h>
  37 #include <vlc_block.h>
  38
  39 /*****************************************************************************
  40  * Local prototypes
  41  *****************************************************************************/
  42 static int  Create    ( vlc_object_t * );
  43 static void Close     ( vlc_object_t * );
  44 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  45                         aout_buffer_t * );
  46
  47 static int  OpenFilter ( vlc_object_t * );
  48 static void CloseFilter( vlc_object_t * );
  49 static block_t *Resample( filter_t *, block_t * );
  50
  51 /*****************************************************************************
  52  * Local structures
  53  *****************************************************************************/
  54 struct filter_sys_t
  55 {
  56     int32_t *p_prev_sample;       /* this filter introduces a 1 sample delay */
  57
  58     unsigned int i_remainder;                /* remainder of previous sample */
  59
  60     audio_date_t end_date;
  61 };
  62
  63 /*****************************************************************************
  64  * Module descriptor
  65  *****************************************************************************/
  66 vlc_module_begin();
  67     set_description( N_("Audio filter for linear interpolation resampling") );
  68     set_category( CAT_AUDIO );
  69     set_subcategory( SUBCAT_AUDIO_MISC );
  70     set_capability( "audio filter", 5 );
  71     set_callbacks( Create, Close );
  72
  73     add_submodule();
  74     set_description( N_("Audio filter for linear interpolation resampling") );
  75     set_capability( "audio filter2", 5 );
  76     set_callbacks( OpenFilter, CloseFilter );
  77 vlc_module_end();
  78
  79 /*****************************************************************************
  80  * Create: allocate linear resampler
  81  *****************************************************************************/
  82 static int Create( vlc_object_t *p_this )
  83 {
  84     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  85     struct filter_sys_t * p_sys;
  86
  87     if ( p_filter->input.i_rate == p_filter->output.i_rate
  88           || p_filter->input.i_format != p_filter->output.i_format
  89           || p_filter->input.i_physical_channels
  90               != p_filter->output.i_physical_channels
  91           || p_filter->input.i_original_channels
  92               != p_filter->output.i_original_channels
  93           || p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
  94     {
  95         return VLC_EGENERIC;
  96     }
  97
  98     /* Allocate the memory needed to store the module's structure */
  99     p_sys = malloc( sizeof(filter_sys_t) );
 100     p_filter->p_sys = (struct aout_filter_sys_t *)p_sys;
 101     if( p_sys == NULL )
 102         return VLC_ENOMEM;
 103     p_sys->p_prev_sample = malloc(
 104         p_filter->input.i_channels * sizeof(int32_t) );
 105     if( p_sys->p_prev_sample == NULL )
 106         return VLC_ENOMEM;
 107     aout_DateInit( &p_sys->end_date, p_filter->output.i_rate );
 108
 109     p_filter->pf_do_work = DoWork;
 110
 111     /* We don't want a new buffer to be created because we're not sure we'll
 112      * actually need to resample anything. */
 113     p_filter->b_in_place = true;
 114
 115     return VLC_SUCCESS;
 116 }
 117
 118 /*****************************************************************************
 119  * Close: free our resources
 120  *****************************************************************************/
 121 static void Close( vlc_object_t * p_this )
 122 {
 123     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 124     filter_sys_t *p_sys = (filter_sys_t *)p_filter->p_sys;
 125
 126     free( p_sys->p_prev_sample );
 127     free( p_sys );
 128 }
 129
 130 /*****************************************************************************
 131  * DoWork: convert a buffer
 132  *****************************************************************************/
 133 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 134                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 135 {
 136     filter_sys_t *p_sys = (filter_sys_t *)p_filter->p_sys;
 137 #ifndef HAVE_ALLOCA
 138     float *p_in_orig;
 139 #endif
 140     float *p_in, *p_out = (float *)p_out_buf->p_buffer;
 141     float *p_prev_sample = (float *)p_sys->p_prev_sample;
 142
 143     int i_nb_channels = p_filter->input.i_channels;
 144     int i_in_nb = p_in_buf->i_nb_samples;
 145     int i_chan, i_in, i_out = 0;
 146
 147     /* Check if we really need to run the resampler */
 148     if( p_aout->mixer.mixer.i_rate == p_filter->input.i_rate )
 149     {
 150         if( p_filter->b_continuity &&
 151             p_in_buf->i_size >=
 152               p_in_buf->i_nb_bytes + sizeof(float) * i_nb_channels )
 153         {
 154             /* output the whole thing with the last sample from last time */
 155             memmove( ((float *)(p_in_buf->p_buffer)) + i_nb_channels,
 156                      p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 157             memcpy( p_in_buf->p_buffer, p_prev_sample,
 158                     i_nb_channels * sizeof(float) );
 159         }
 160         p_filter->b_continuity = false;
 161         return;
 162     }
 163
 164 #ifdef HAVE_ALLOCA
 165     p_in = (float *)alloca( p_in_buf->i_nb_bytes );
 166 #else
 167     p_in_orig = p_in = (float *)malloc( p_in_buf->i_nb_bytes );
 168 #endif
 169     if( p_in == NULL )
 170     {
 171         return;
 172     }
 173
 174     vlc_memcpy( p_in, p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 175
 176     /* Take care of the previous input sample (if any) */
 177     if( !p_filter->b_continuity )
 178     {
 179         p_filter->b_continuity = true;
 180         p_sys->i_remainder = 0;
 181         aout_DateInit( &p_sys->end_date, p_filter->output.i_rate );
 182     }
 183     else
 184     {
 185         while( p_sys->i_remainder < p_filter->output.i_rate )
 186         {
 187             for( i_chan = i_nb_channels ; i_chan ; )
 188             {
 189                 i_chan--;
 190                 p_out[i_chan] = p_prev_sample[i_chan];
 191                 p_out[i_chan] += ( ( p_in[i_chan] - p_prev_sample[i_chan] )
 192                                    * p_sys->i_remainder
 193                                    / p_filter->output.i_rate );
 194             }
 195             p_out += i_nb_channels;
 196               i_out++;
 197
 198             p_sys->i_remainder += p_filter->input.i_rate;
 199         }
 200         p_sys->i_remainder -= p_filter->output.i_rate;
 201     }
 202
 203     /* Take care of the current input samples (minus last one) */
 204     for( i_in = 0; i_in < i_in_nb - 1; i_in++ )
 205     {
 206         while( p_sys->i_remainder < p_filter->output.i_rate )
 207         {
 208             for( i_chan = i_nb_channels ; i_chan ; )
 209             {
 210                 i_chan--;
 211                 p_out[i_chan] = p_in[i_chan];
 212                 p_out[i_chan] += ( ( p_in[i_chan + i_nb_channels]
 213                     - p_in[i_chan] )
 214                     * p_sys->i_remainder / p_filter->output.i_rate );
 215             }
 216             p_out += i_nb_channels;
 217               i_out++;
 218
 219             p_sys->i_remainder += p_filter->input.i_rate;
 220         }
 221
 222         p_in += i_nb_channels;
 223         p_sys->i_remainder -= p_filter->output.i_rate;
 224     }
 225
 226     /* Backup the last input sample for next time */
 227     for( i_chan = i_nb_channels ; i_chan ; )
 228     {
 229         i_chan--;
 230         p_prev_sample[i_chan] = p_in[i_chan];
 231     }
 232
 233     p_out_buf->i_nb_samples = i_out;
 234     p_out_buf->start_date = p_in_buf->start_date;
 235
 236     if( p_in_buf->start_date !=
 237         aout_DateGet( &p_sys->end_date ) )
 238     {
 239         aout_DateSet( &p_sys->end_date, p_in_buf->start_date );
 240     }
 241
 242     p_out_buf->end_date = aout_DateIncrement( &p_sys->end_date,
 243                                               p_out_buf->i_nb_samples );
 244
 245     p_out_buf->i_nb_bytes = p_out_buf->i_nb_samples *
 246         i_nb_channels * sizeof(int32_t);
 247
 248 #ifndef HAVE_ALLOCA
 249     free( p_in_orig );
 250 #endif
 251
 252 }
 253
 254 /*****************************************************************************
 255  * OpenFilter:
 256  *****************************************************************************/
 257 static int OpenFilter( vlc_object_t *p_this )
 258 {
 259     filter_t *p_filter = (filter_t *)p_this;
 260     filter_sys_t *p_sys;
 261     int i_out_rate  = p_filter->fmt_out.audio.i_rate;
 262
 263     if( p_filter->fmt_in.audio.i_rate == p_filter->fmt_out.audio.i_rate ||
 264         p_filter->fmt_in.i_codec != VLC_FOURCC('f','l','3','2') )
 265     {
 266         return VLC_EGENERIC;
 267     }
 268
 269     /* Allocate the memory needed to store the module's structure */
 270     p_filter->p_sys = p_sys = malloc( sizeof(struct filter_sys_t) );
 271     if( p_sys == NULL )
 272         return VLC_ENOMEM;
 273
 274     p_sys->p_prev_sample = malloc(
 275         p_filter->fmt_in.audio.i_channels * sizeof(int32_t) );
 276     if( p_sys->p_prev_sample == NULL )
 277     {
 278         free( p_sys );
 279         return VLC_ENOMEM;
 280     }
 281     aout_DateInit( &p_sys->end_date, p_filter->fmt_in.audio.i_rate );
 282
 283     p_filter->pf_audio_filter = Resample;
 284
 285     msg_Dbg( p_this, "%4.4s/%iKHz/%i->%4.4s/%iKHz/%i",
 286              (char *)&p_filter->fmt_in.i_codec,
 287              p_filter->fmt_in.audio.i_rate,
 288              p_filter->fmt_in.audio.i_channels,
 289              (char *)&p_filter->fmt_out.i_codec,
 290              p_filter->fmt_out.audio.i_rate,
 291              p_filter->fmt_out.audio.i_channels);
 292
 293     p_filter->fmt_out = p_filter->fmt_in;
 294     p_filter->fmt_out.audio.i_rate = i_out_rate;
 295
 296     return 0;
 297 }
 298
 299 /*****************************************************************************
 300  * CloseFilter : deallocate data structures
 301  *****************************************************************************/
 302 static void CloseFilter( vlc_object_t *p_this )
 303 {
 304     filter_t *p_filter = (filter_t *)p_this;
 305     free( p_filter->p_sys->p_prev_sample );
 306     free( p_filter->p_sys );
 307 }
 308
 309 /*****************************************************************************
 310  * Resample
 311  *****************************************************************************/
 312 static block_t *Resample( filter_t *p_filter, block_t *p_block )
 313 {
 314     aout_filter_t aout_filter;
 315     aout_buffer_t in_buf, out_buf;
 316     block_t *p_out;
 317     int i_out_size;
 318     int i_bytes_per_frame;
 319
 320     if( !p_block || !p_block->i_samples )
 321     {
 322         if( p_block ) p_block->pf_release( p_block );
 323         return NULL;
 324     }
 325
 326     i_bytes_per_frame = p_filter->fmt_out.audio.i_channels *
 327                   p_filter->fmt_out.audio.i_bitspersample / 8;
 328
 329     i_out_size = i_bytes_per_frame * ( 1 + (p_block->i_samples *
 330         p_filter->fmt_out.audio.i_rate / p_filter->fmt_in.audio.i_rate));
 331
 332     p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
 333     if( !p_out )
 334     {
 335         msg_Warn( p_filter, "can't get output buffer" );
 336         p_block->pf_release( p_block );
 337         return NULL;
 338     }
 339
 340     p_out->i_samples = i_out_size / i_bytes_per_frame;
 341     p_out->i_dts = p_block->i_dts;
 342     p_out->i_pts = p_block->i_pts;
 343     p_out->i_length = p_block->i_length;
 344
 345     aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
 346     aout_filter.input = p_filter->fmt_in.audio;
 347     aout_filter.output = p_filter->fmt_out.audio;
 348     aout_filter.b_continuity = false;
 349
 350     in_buf.p_buffer = p_block->p_buffer;
 351     in_buf.i_nb_bytes = p_block->i_buffer;
 352     in_buf.i_nb_samples = p_block->i_samples;
 353     out_buf.p_buffer = p_out->p_buffer;
 354     out_buf.i_nb_bytes = p_out->i_buffer;
 355     out_buf.i_nb_samples = p_out->i_samples;
 356
 357     DoWork( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf );
 358
 359     p_block->pf_release( p_block );
 360
 361     p_out->i_buffer = out_buf.i_nb_bytes;
 362     p_out->i_samples = out_buf.i_nb_samples;
 363
 364     return p_out;
 365 }