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/vlc.h>
  34 #include <vlc_aout.h>
  35 #include <vlc_filter.h>
  36 #include <vlc_block.h>
  37
  38 /*****************************************************************************
  39  * Local prototypes
  40  *****************************************************************************/
  41 static int  Create    ( vlc_object_t * );
  42 static void Close     ( vlc_object_t * );
  43 static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
  44                         aout_buffer_t * );
  45
  46 static int  OpenFilter ( vlc_object_t * );
  47 static void CloseFilter( vlc_object_t * );
  48 static block_t *Resample( filter_t *, block_t * );
  49
  50 /*****************************************************************************
  51  * Local structures
  52  *****************************************************************************/
  53 struct filter_sys_t
  54 {
  55     int32_t *p_prev_sample;       /* this filter introduces a 1 sample delay */
  56
  57     unsigned int i_remainder;                /* remainder of previous sample */
  58
  59     audio_date_t end_date;
  60 };
  61
  62 /*****************************************************************************
  63  * Module descriptor
  64  *****************************************************************************/
  65 vlc_module_begin();
  66     set_description( _("Audio filter for linear interpolation resampling") );
  67     set_category( CAT_AUDIO );
  68     set_subcategory( SUBCAT_AUDIO_MISC );
  69     set_capability( "audio filter", 5 );
  70     set_callbacks( Create, Close );
  71
  72     add_submodule();
  73     set_description( _("Audio filter for linear interpolation resampling") );
  74     set_capability( "audio filter2", 5 );
  75     set_callbacks( OpenFilter, CloseFilter );
  76 vlc_module_end();
  77
  78 /*****************************************************************************
  79  * Create: allocate linear resampler
  80  *****************************************************************************/
  81 static int Create( vlc_object_t *p_this )
  82 {
  83     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  84     struct filter_sys_t * p_sys;
  85
  86     if ( p_filter->input.i_rate == p_filter->output.i_rate
  87           || p_filter->input.i_format != p_filter->output.i_format
  88           || p_filter->input.i_physical_channels
  89               != p_filter->output.i_physical_channels
  90           || p_filter->input.i_original_channels
  91               != p_filter->output.i_original_channels
  92           || p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
  93     {
  94         return VLC_EGENERIC;
  95     }
  96
  97     /* Allocate the memory needed to store the module's structure */
  98     p_sys = malloc( sizeof(filter_sys_t) );
  99     p_filter->p_sys = (struct aout_filter_sys_t *)p_sys;
 100     if( p_sys == NULL )
 101     {
 102         msg_Err( p_filter, "out of memory" );
 103         return VLC_ENOMEM;
 104     }
 105     p_sys->p_prev_sample = malloc(
 106         p_filter->input.i_channels * sizeof(int32_t) );
 107     if( p_sys->p_prev_sample == NULL )
 108     {
 109         msg_Err( p_filter, "out of memory" );
 110         return VLC_ENOMEM;
 111     }
 112     aout_DateInit( &p_sys->end_date, p_filter->output.i_rate );
 113
 114     p_filter->pf_do_work = DoWork;
 115
 116     /* We don't want a new buffer to be created because we're not sure we'll
 117      * actually need to resample anything. */
 118     p_filter->b_in_place = true;
 119
 120     return VLC_SUCCESS;
 121 }
 122
 123 /*****************************************************************************
 124  * Close: free our resources
 125  *****************************************************************************/
 126 static void Close( vlc_object_t * p_this )
 127 {
 128     aout_filter_t * p_filter = (aout_filter_t *)p_this;
 129     filter_sys_t *p_sys = (filter_sys_t *)p_filter->p_sys;
 130
 131     free( p_sys->p_prev_sample );
 132     free( p_sys );
 133 }
 134
 135 /*****************************************************************************
 136  * DoWork: convert a buffer
 137  *****************************************************************************/
 138 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
 139                     aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
 140 {
 141     filter_sys_t *p_sys = (filter_sys_t *)p_filter->p_sys;
 142 #ifndef HAVE_ALLOCA
 143     float *p_in_orig;
 144 #endif
 145     float *p_in, *p_out = (float *)p_out_buf->p_buffer;
 146     float *p_prev_sample = (float *)p_sys->p_prev_sample;
 147
 148     int i_nb_channels = p_filter->input.i_channels;
 149     int i_in_nb = p_in_buf->i_nb_samples;
 150     int i_chan, i_in, i_out = 0;
 151
 152     /* Check if we really need to run the resampler */
 153     if( p_aout->mixer.mixer.i_rate == p_filter->input.i_rate )
 154     {
 155         if( p_filter->b_continuity &&
 156             p_in_buf->i_size >=
 157               p_in_buf->i_nb_bytes + sizeof(float) * i_nb_channels )
 158         {
 159             /* output the whole thing with the last sample from last time */
 160             memmove( ((float *)(p_in_buf->p_buffer)) + i_nb_channels,
 161                      p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 162             memcpy( p_in_buf->p_buffer, p_prev_sample,
 163                     i_nb_channels * sizeof(float) );
 164         }
 165         p_filter->b_continuity = false;
 166         return;
 167     }
 168
 169 #ifdef HAVE_ALLOCA
 170     p_in = (float *)alloca( p_in_buf->i_nb_bytes );
 171 #else
 172     p_in_orig = p_in = (float *)malloc( p_in_buf->i_nb_bytes );
 173 #endif
 174     if( p_in == NULL )
 175     {
 176         return;
 177     }
 178
 179     p_aout->p_libvlc->pf_memcpy( p_in, p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 180
 181     /* Take care of the previous input sample (if any) */
 182     if( !p_filter->b_continuity )
 183     {
 184         p_filter->b_continuity = true;
 185         p_sys->i_remainder = 0;
 186         aout_DateInit( &p_sys->end_date, p_filter->output.i_rate );
 187     }
 188     else
 189     {
 190         while( p_sys->i_remainder < p_filter->output.i_rate )
 191         {
 192             for( i_chan = i_nb_channels ; i_chan ; )
 193             {
 194                 i_chan--;
 195                 p_out[i_chan] = p_prev_sample[i_chan];
 196                 p_out[i_chan] += ( ( p_in[i_chan] - p_prev_sample[i_chan] )
 197                                    * p_sys->i_remainder
 198                                    / p_filter->output.i_rate );
 199             }
 200             p_out += i_nb_channels;
 201               i_out++;
 202
 203             p_sys->i_remainder += p_filter->input.i_rate;
 204         }
 205         p_sys->i_remainder -= p_filter->output.i_rate;
 206     }
 207
 208     /* Take care of the current input samples (minus last one) */
 209     for( i_in = 0; i_in < i_in_nb - 1; i_in++ )
 210     {
 211         while( p_sys->i_remainder < p_filter->output.i_rate )
 212         {
 213             for( i_chan = i_nb_channels ; i_chan ; )
 214             {
 215                 i_chan--;
 216                 p_out[i_chan] = p_in[i_chan];
 217                 p_out[i_chan] += ( ( p_in[i_chan + i_nb_channels]
 218                     - p_in[i_chan] )
 219                     * p_sys->i_remainder / p_filter->output.i_rate );
 220             }
 221             p_out += i_nb_channels;
 222               i_out++;
 223
 224             p_sys->i_remainder += p_filter->input.i_rate;
 225         }
 226
 227         p_in += i_nb_channels;
 228         p_sys->i_remainder -= p_filter->output.i_rate;
 229     }
 230
 231     /* Backup the last input sample for next time */
 232     for( i_chan = i_nb_channels ; i_chan ; )
 233     {
 234         i_chan--;
 235         p_prev_sample[i_chan] = p_in[i_chan];
 236     }
 237
 238     p_out_buf->i_nb_samples = i_out;
 239     p_out_buf->start_date = p_in_buf->start_date;
 240
 241     if( p_in_buf->start_date !=
 242         aout_DateGet( &p_sys->end_date ) )
 243     {
 244         aout_DateSet( &p_sys->end_date, p_in_buf->start_date );
 245     }
 246
 247     p_out_buf->end_date = aout_DateIncrement( &p_sys->end_date,
 248                                               p_out_buf->i_nb_samples );
 249
 250     p_out_buf->i_nb_bytes = p_out_buf->i_nb_samples *
 251         i_nb_channels * sizeof(int32_t);
 252
 253 #ifndef HAVE_ALLOCA
 254     free( p_in_orig );
 255 #endif
 256
 257 }
 258
 259 /*****************************************************************************
 260  * OpenFilter:
 261  *****************************************************************************/
 262 static int OpenFilter( vlc_object_t *p_this )
 263 {
 264     filter_t *p_filter = (filter_t *)p_this;
 265     filter_sys_t *p_sys;
 266     int i_out_rate  = p_filter->fmt_out.audio.i_rate;
 267
 268     if( p_filter->fmt_in.audio.i_rate == p_filter->fmt_out.audio.i_rate ||
 269         p_filter->fmt_in.i_codec != VLC_FOURCC('f','l','3','2') )
 270     {
 271         return VLC_EGENERIC;
 272     }
 273
 274     /* Allocate the memory needed to store the module's structure */
 275     p_filter->p_sys = p_sys = malloc( sizeof(struct filter_sys_t) );
 276     if( p_sys == NULL )
 277     {
 278         msg_Err( p_filter, "out of memory" );
 279         return VLC_ENOMEM;
 280     }
 281
 282     p_sys->p_prev_sample = malloc(
 283         p_filter->fmt_in.audio.i_channels * sizeof(int32_t) );
 284     if( p_sys->p_prev_sample == NULL )
 285     {
 286         msg_Err( p_filter, "out of memory" );
 287         free( p_sys );
 288         return VLC_ENOMEM;
 289     }
 290     aout_DateInit( &p_sys->end_date, p_filter->fmt_in.audio.i_rate );
 291
 292     p_filter->pf_audio_filter = Resample;
 293
 294     msg_Dbg( p_this, "%4.4s/%iKHz/%i->%4.4s/%iKHz/%i",
 295              (char *)&p_filter->fmt_in.i_codec,
 296              p_filter->fmt_in.audio.i_rate,
 297              p_filter->fmt_in.audio.i_channels,
 298              (char *)&p_filter->fmt_out.i_codec,
 299              p_filter->fmt_out.audio.i_rate,
 300              p_filter->fmt_out.audio.i_channels);
 301
 302     p_filter->fmt_out = p_filter->fmt_in;
 303     p_filter->fmt_out.audio.i_rate = i_out_rate;
 304
 305     return 0;
 306 }
 307
 308 /*****************************************************************************
 309  * CloseFilter : deallocate data structures
 310  *****************************************************************************/
 311 static void CloseFilter( vlc_object_t *p_this )
 312 {
 313     filter_t *p_filter = (filter_t *)p_this;
 314     free( p_filter->p_sys->p_prev_sample );
 315     free( p_filter->p_sys );
 316 }
 317
 318 /*****************************************************************************
 319  * Resample
 320  *****************************************************************************/
 321 static block_t *Resample( filter_t *p_filter, block_t *p_block )
 322 {
 323     aout_filter_t aout_filter;
 324     aout_buffer_t in_buf, out_buf;
 325     block_t *p_out;
 326     int i_out_size;
 327     int i_bytes_per_frame;
 328
 329     if( !p_block || !p_block->i_samples )
 330     {
 331         if( p_block ) p_block->pf_release( p_block );
 332         return NULL;
 333     }
 334
 335     i_bytes_per_frame = p_filter->fmt_out.audio.i_channels *
 336                   p_filter->fmt_out.audio.i_bitspersample / 8;
 337
 338     i_out_size = i_bytes_per_frame * ( 1 + (p_block->i_samples *
 339         p_filter->fmt_out.audio.i_rate / p_filter->fmt_in.audio.i_rate));
 340
 341     p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
 342     if( !p_out )
 343     {
 344         msg_Warn( p_filter, "can't get output buffer" );
 345         p_block->pf_release( p_block );
 346         return NULL;
 347     }
 348
 349     p_out->i_samples = i_out_size / i_bytes_per_frame;
 350     p_out->i_dts = p_block->i_dts;
 351     p_out->i_pts = p_block->i_pts;
 352     p_out->i_length = p_block->i_length;
 353
 354     aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
 355     aout_filter.input = p_filter->fmt_in.audio;
 356     aout_filter.output = p_filter->fmt_out.audio;
 357     aout_filter.b_continuity = false;
 358
 359     in_buf.p_buffer = p_block->p_buffer;
 360     in_buf.i_nb_bytes = p_block->i_buffer;
 361     in_buf.i_nb_samples = p_block->i_samples;
 362     out_buf.p_buffer = p_out->p_buffer;
 363     out_buf.i_nb_bytes = p_out->i_buffer;
 364     out_buf.i_nb_samples = p_out->i_samples;
 365
 366     DoWork( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf );
 367
 368     p_block->pf_release( p_block );
 369
 370     p_out->i_buffer = out_buf.i_nb_bytes;
 371     p_out->i_samples = out_buf.i_nb_samples;
 372
 373     return p_out;
 374 }