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