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