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 #include <stdlib.h>                                      /* malloc(), free() */
  29 #include <string.h>
  30
  31 #include <vlc/vlc.h>
  32 #include <vlc_aout.h>
  33
  34 #include <vlc_filter.h>
  35 #include <vlc_block.h>
  36
  37 /*****************************************************************************
  38  * Local prototypes
  39  *****************************************************************************/
  40 static int  Create    ( vlc_object_t * );
  41 static void Close     ( vlc_object_t * );
  42 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  43                         aout_buffer_t * );
  44 static void DoWork_inner( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  45                         aout_buffer_t *, int );
  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( _("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( _("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     {
 103         msg_Err( p_filter, "out of memory" );
 104         return VLC_ENOMEM;
 105     }
 106     p_sys->p_prev_sample = malloc(
 107         p_filter->input.i_channels * sizeof(int32_t) );
 108     if( p_sys->p_prev_sample == NULL )
 109     {
 110         msg_Err( p_filter, "out of memory" );
 111         return VLC_ENOMEM;
 112     }
 113
 114     memset( p_sys->p_prev_sample, 0, aout_FormatNbChannels( &p_filter->input ) * sizeof(int32_t) );
 115
 116     p_filter->pf_do_work = DoWork;
 117
 118     /* We don't want a new buffer to be created because we're not sure we'll
 119      * actually need to resample anything. */
 120     p_filter->b_in_place = VLC_TRUE;
 121
 122     return VLC_SUCCESS;
 123 }
 124
 125 /*****************************************************************************
 126  * Close: free our resources
 127  *****************************************************************************/
 128 static void Close( vlc_object_t * p_this )
 129 {
 130     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 131     filter_sys_t *p_sys = (filter_sys_t *)p_filter->p_sys;
 132
 133     free( p_sys->p_prev_sample );
 134     free( p_sys );
 135 }
 136
 137 /*****************************************************************************
 138  * DoWork: convert a buffer
 139  *****************************************************************************/
 140 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 141                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 142 {
 143     DoWork_inner( p_aout, p_filter, p_in_buf, p_out_buf, p_aout->mixer.mixer.i_rate );
 144 }
 145
 146 static void DoWork_inner( aout_instance_t * p_aout, aout_filter_t * p_filter,
 147                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf,
 148                     int i_output_rate )
 149 {
 150     filter_sys_t *p_sys = (filter_sys_t *)p_filter->p_sys;
 151 #ifndef HAVE_ALLOCA
 152     float *p_in_orig;
 153 #endif
 154     float *p_in, *p_out = (float *)p_out_buf->p_buffer;
 155     float *p_prev_sample = (float *)p_sys->p_prev_sample;
 156
 157     int i_nb_channels = p_filter->input.i_channels;
 158     int i_in_nb = p_in_buf->i_nb_samples;
 159     int i_chan, i_in, i_out = 0;
 160
 161
 162     /* Check if we really need to run the resampler */
 163     //if( p_aout->mixer.mixer.i_rate == p_filter->input.i_rate )
 164     if( i_output_rate == p_filter->input.i_rate )
 165     {
 166         if( p_filter->b_continuity &&
 167             p_in_buf->i_size >=
 168               p_in_buf->i_nb_bytes + sizeof(float) * i_nb_channels )
 169         {
 170             /* output the whole thing with the last sample from last time */
 171             memmove( ((float *)(p_in_buf->p_buffer)) + i_nb_channels,
 172                      p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 173             memcpy( p_in_buf->p_buffer, p_prev_sample,
 174                     i_nb_channels * sizeof(float) );
 175         }
 176         p_filter->b_continuity = VLC_FALSE;
 177         return;
 178     }
 179
 180 #ifdef HAVE_ALLOCA
 181     p_in = (float *)alloca( p_in_buf->i_nb_bytes );
 182 #else
 183     p_in_orig = p_in = (float *)malloc( p_in_buf->i_nb_bytes );
 184 #endif
 185     if( p_in == NULL )
 186     {
 187         return;
 188     }
 189
 190     p_aout->p_libvlc->pf_memcpy( p_in, p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 191
 192     /* Take care of the previous input sample (if any) */
 193     if( !p_filter->b_continuity )
 194     {
 195         p_filter->b_continuity = VLC_TRUE;
 196         p_sys->i_remainder = 0;
 197         aout_DateInit( &p_sys->end_date, p_filter->output.i_rate );
 198     }
 199     else
 200     {
 201         while( p_sys->i_remainder < p_filter->output.i_rate )
 202         {
 203             for( i_chan = i_nb_channels ; i_chan ; )
 204             {
 205                 i_chan--;
 206                 p_out[i_chan] = p_prev_sample[i_chan];
 207                 p_out[i_chan] += ( ( p_in[i_chan] - p_prev_sample[i_chan] )
 208                                    * p_sys->i_remainder
 209                                    / p_filter->output.i_rate );
 210             }
 211             p_out += i_nb_channels;
 212               i_out++;
 213
 214             p_sys->i_remainder += p_filter->input.i_rate;
 215         }
 216         p_sys->i_remainder -= p_filter->output.i_rate;
 217     }
 218
 219     /* Take care of the current input samples (minus last one) */
 220     for( i_in = 0; i_in < i_in_nb - 1; i_in++ )
 221     {
 222         while( p_sys->i_remainder < p_filter->output.i_rate )
 223         {
 224             for( i_chan = i_nb_channels ; i_chan ; )
 225             {
 226                 i_chan--;
 227                 p_out[i_chan] = p_in[i_chan];
 228                 p_out[i_chan] += ( ( p_in[i_chan + i_nb_channels]
 229                     - p_in[i_chan] )
 230                     * p_sys->i_remainder / p_filter->output.i_rate );
 231             }
 232             p_out += i_nb_channels;
 233               i_out++;
 234
 235             p_sys->i_remainder += p_filter->input.i_rate;
 236         }
 237
 238         p_in += i_nb_channels;
 239         p_sys->i_remainder -= p_filter->output.i_rate;
 240     }
 241
 242     /* Backup the last input sample for next time */
 243     for( i_chan = i_nb_channels ; i_chan ; )
 244     {
 245         i_chan--;
 246         p_prev_sample[i_chan] = p_in[i_chan];
 247     }
 248
 249     p_out_buf->i_nb_samples = i_out;
 250     p_out_buf->start_date = p_in_buf->start_date;
 251
 252     if( p_in_buf->start_date !=
 253         aout_DateGet( &p_sys->end_date ) )
 254     {
 255         aout_DateSet( &p_sys->end_date, p_in_buf->start_date );
 256     }
 257
 258     p_out_buf->end_date = aout_DateIncrement( &p_sys->end_date,
 259                                               p_out_buf->i_nb_samples );
 260
 261     p_out_buf->i_nb_bytes = p_out_buf->i_nb_samples *
 262         i_nb_channels * sizeof(int32_t);
 263
 264 #ifndef HAVE_ALLOCA
 265     free( p_in_orig );
 266 #endif
 267
 268 }
 269
 270 /*****************************************************************************
 271  * OpenFilter:
 272  *****************************************************************************/
 273 static int OpenFilter( vlc_object_t *p_this )
 274 {
 275     filter_t *p_filter = (filter_t *)p_this;
 276     filter_sys_t *p_sys;
 277     int i_out_rate  = p_filter->fmt_out.audio.i_rate;
 278
 279     if( p_filter->fmt_in.audio.i_rate == p_filter->fmt_out.audio.i_rate ||
 280         p_filter->fmt_in.i_codec != VLC_FOURCC('f','l','3','2') )
 281     {
 282         return VLC_EGENERIC;
 283     }
 284
 285     /* Allocate the memory needed to store the module's structure */
 286     p_filter->p_sys = p_sys = malloc( sizeof(struct filter_sys_t) );
 287     if( p_sys == NULL )
 288     {
 289         msg_Err( p_filter, "out of memory" );
 290         return VLC_ENOMEM;
 291     }
 292
 293     p_sys->p_prev_sample = malloc(
 294         p_filter->fmt_in.audio.i_channels * sizeof(int32_t) );
 295     if( p_sys->p_prev_sample == NULL )
 296     {
 297         msg_Err( p_filter, "out of memory" );
 298         free( p_sys );
 299         return VLC_ENOMEM;
 300     }
 301
 302     memset( p_sys->p_prev_sample, 0, p_filter->fmt_in.audio.i_channels * sizeof(int32_t) );
 303
 304     p_filter->pf_audio_filter = Resample;
 305
 306     msg_Dbg( p_this, "%4.4s/%iKHz/%i->%4.4s/%iKHz/%i",
 307              (char *)&p_filter->fmt_in.i_codec,
 308              p_filter->fmt_in.audio.i_rate,
 309              p_filter->fmt_in.audio.i_channels,
 310              (char *)&p_filter->fmt_out.i_codec,
 311              p_filter->fmt_out.audio.i_rate,
 312              p_filter->fmt_out.audio.i_channels);
 313
 314     p_filter->fmt_out = p_filter->fmt_in;
 315     p_filter->fmt_out.audio.i_rate = i_out_rate;
 316
 317     return 0;
 318 }
 319
 320 /*****************************************************************************
 321  * CloseFilter : deallocate data structures
 322  *****************************************************************************/
 323 static void CloseFilter( vlc_object_t *p_this )
 324 {
 325     filter_t *p_filter = (filter_t *)p_this;
 326     free( p_filter->p_sys->p_prev_sample );
 327     free( p_filter->p_sys );
 328 }
 329
 330 /*****************************************************************************
 331  * Resample
 332  *****************************************************************************/
 333 static block_t *Resample( filter_t *p_filter, block_t *p_block )
 334 {
 335     aout_filter_t aout_filter;
 336     aout_buffer_t in_buf, out_buf;
 337     block_t *p_out;
 338     int i_out_size;
 339     int i_bytes_per_frame;
 340
 341     if( !p_block || !p_block->i_samples )
 342     {
 343         if( p_block ) p_block->pf_release( p_block );
 344         return NULL;
 345     }
 346
 347     i_bytes_per_frame = p_filter->fmt_out.audio.i_channels *
 348                   p_filter->fmt_out.audio.i_bitspersample / 8;
 349
 350     i_out_size = i_bytes_per_frame * ( 1 + (p_block->i_samples *
 351         p_filter->fmt_out.audio.i_rate / p_filter->fmt_in.audio.i_rate));
 352
 353     p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
 354     if( !p_out )
 355     {
 356         msg_Warn( p_filter, "can't get output buffer" );
 357         p_block->pf_release( p_block );
 358         return NULL;
 359     }
 360
 361     p_out->i_samples = i_out_size / i_bytes_per_frame;
 362     p_out->i_dts = p_block->i_dts;
 363     p_out->i_pts = p_block->i_pts;
 364     p_out->i_length = p_block->i_length;
 365
 366     aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
 367     aout_filter.input = p_filter->fmt_in.audio;
 368     aout_filter.output = p_filter->fmt_out.audio;
 369     aout_filter.b_continuity = VLC_FALSE;
 370
 371     in_buf.p_buffer = p_block->p_buffer;
 372     in_buf.i_nb_bytes = p_block->i_buffer;
 373     in_buf.i_nb_samples = p_block->i_samples;
 374     out_buf.p_buffer = p_out->p_buffer;
 375     out_buf.i_nb_bytes = p_out->i_buffer;
 376     out_buf.i_nb_samples = p_out->i_samples;
 377
 378     DoWork_inner( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf,
 379                                             p_filter->fmt_out.audio.i_rate );
 380
 381     p_block->pf_release( p_block );
 382
 383     p_out->i_buffer = out_buf.i_nb_bytes;
 384     p_out->i_samples = out_buf.i_nb_samples;
 385
 386     return p_out;
 387 }