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_CODEC_FL32 )
  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     float *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     float p_in_orig[p_in_buf->i_nb_bytes / 4], *p_in = p_in_orig;
 165
 166     vlc_memcpy( p_in, p_in_buf->p_buffer, p_in_buf->i_nb_bytes );
 167
 168     /* Take care of the previous input sample (if any) */
 169     if( !p_filter->b_continuity )
 170     {
 171         p_filter->b_continuity = true;
 172         p_sys->i_remainder = 0;
 173         aout_DateInit( &p_sys->end_date, p_filter->output.i_rate );
 174     }
 175     else
 176     {
 177         while( p_sys->i_remainder < p_filter->output.i_rate )
 178         {
 179             for( i_chan = i_nb_channels ; i_chan ; )
 180             {
 181                 i_chan--;
 182                 p_out[i_chan] = p_prev_sample[i_chan];
 183                 p_out[i_chan] += ( ( p_in[i_chan] - p_prev_sample[i_chan] )
 184                                    * p_sys->i_remainder
 185                                    / p_filter->output.i_rate );
 186             }
 187             p_out += i_nb_channels;
 188               i_out++;
 189
 190             p_sys->i_remainder += p_filter->input.i_rate;
 191         }
 192         p_sys->i_remainder -= p_filter->output.i_rate;
 193     }
 194
 195     /* Take care of the current input samples (minus last one) */
 196     for( i_in = 0; i_in < i_in_nb - 1; i_in++ )
 197     {
 198         while( p_sys->i_remainder < p_filter->output.i_rate )
 199         {
 200             for( i_chan = i_nb_channels ; i_chan ; )
 201             {
 202                 i_chan--;
 203                 p_out[i_chan] = p_in[i_chan];
 204                 p_out[i_chan] += ( ( p_in[i_chan + i_nb_channels]
 205                     - p_in[i_chan] )
 206                     * p_sys->i_remainder / p_filter->output.i_rate );
 207             }
 208             p_out += i_nb_channels;
 209               i_out++;
 210
 211             p_sys->i_remainder += p_filter->input.i_rate;
 212         }
 213
 214         p_in += i_nb_channels;
 215         p_sys->i_remainder -= p_filter->output.i_rate;
 216     }
 217
 218     /* Backup the last input sample for next time */
 219     for( i_chan = i_nb_channels ; i_chan ; )
 220     {
 221         i_chan--;
 222         p_prev_sample[i_chan] = p_in[i_chan];
 223     }
 224
 225     p_out_buf->i_nb_samples = i_out;
 226     p_out_buf->start_date = p_in_buf->start_date;
 227
 228     if( p_in_buf->start_date !=
 229         aout_DateGet( &p_sys->end_date ) )
 230     {
 231         aout_DateSet( &p_sys->end_date, p_in_buf->start_date );
 232     }
 233
 234     p_out_buf->end_date = aout_DateIncrement( &p_sys->end_date,
 235                                               p_out_buf->i_nb_samples );
 236
 237     p_out_buf->i_nb_bytes = p_out_buf->i_nb_samples *
 238         i_nb_channels * sizeof(int32_t);
 239 }
 240
 241 /*****************************************************************************
 242  * OpenFilter:
 243  *****************************************************************************/
 244 static int OpenFilter( vlc_object_t *p_this )
 245 {
 246     filter_t *p_filter = (filter_t *)p_this;
 247     filter_sys_t *p_sys;
 248     int i_out_rate  = p_filter->fmt_out.audio.i_rate;
 249
 250     if( p_filter->fmt_in.audio.i_rate == p_filter->fmt_out.audio.i_rate ||
 251         p_filter->fmt_in.i_codec != VLC_CODEC_FL32 )
 252     {
 253         return VLC_EGENERIC;
 254     }
 255
 256     /* Allocate the memory needed to store the module's structure */
 257     p_filter->p_sys = p_sys = malloc( sizeof(struct filter_sys_t) );
 258     if( p_sys == NULL )
 259         return VLC_ENOMEM;
 260
 261     p_sys->p_prev_sample = malloc(
 262         p_filter->fmt_in.audio.i_channels * sizeof(int32_t) );
 263     if( p_sys->p_prev_sample == NULL )
 264     {
 265         free( p_sys );
 266         return VLC_ENOMEM;
 267     }
 268     aout_DateInit( &p_sys->end_date, p_filter->fmt_in.audio.i_rate );
 269
 270     p_filter->pf_audio_filter = Resample;
 271
 272     msg_Dbg( p_this, "%4.4s/%iKHz/%i->%4.4s/%iKHz/%i",
 273              (char *)&p_filter->fmt_in.i_codec,
 274              p_filter->fmt_in.audio.i_rate,
 275              p_filter->fmt_in.audio.i_channels,
 276              (char *)&p_filter->fmt_out.i_codec,
 277              p_filter->fmt_out.audio.i_rate,
 278              p_filter->fmt_out.audio.i_channels);
 279
 280     p_filter->fmt_out = p_filter->fmt_in;
 281     p_filter->fmt_out.audio.i_rate = i_out_rate;
 282
 283     return 0;
 284 }
 285
 286 /*****************************************************************************
 287  * CloseFilter : deallocate data structures
 288  *****************************************************************************/
 289 static void CloseFilter( vlc_object_t *p_this )
 290 {
 291     filter_t *p_filter = (filter_t *)p_this;
 292     free( p_filter->p_sys->p_prev_sample );
 293     free( p_filter->p_sys );
 294 }
 295
 296 /*****************************************************************************
 297  * Resample
 298  *****************************************************************************/
 299 static block_t *Resample( filter_t *p_filter, block_t *p_block )
 300 {
 301     aout_filter_t aout_filter;
 302     aout_buffer_t in_buf, out_buf;
 303     block_t *p_out;
 304     int i_out_size;
 305     int i_bytes_per_frame;
 306
 307     if( !p_block || !p_block->i_samples )
 308     {
 309         if( p_block )
 310             block_Release( p_block );
 311         return NULL;
 312     }
 313
 314     i_bytes_per_frame = p_filter->fmt_out.audio.i_channels *
 315                   p_filter->fmt_out.audio.i_bitspersample / 8;
 316
 317     i_out_size = i_bytes_per_frame * ( 1 + (p_block->i_samples *
 318         p_filter->fmt_out.audio.i_rate / p_filter->fmt_in.audio.i_rate));
 319
 320     p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
 321     if( !p_out )
 322     {
 323         msg_Warn( p_filter, "can't get output buffer" );
 324         block_Release( p_block );
 325         return NULL;
 326     }
 327
 328     p_out->i_samples = i_out_size / i_bytes_per_frame;
 329     p_out->i_dts = p_block->i_dts;
 330     p_out->i_pts = p_block->i_pts;
 331     p_out->i_length = p_block->i_length;
 332
 333     aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
 334     aout_filter.input = p_filter->fmt_in.audio;
 335     aout_filter.output = p_filter->fmt_out.audio;
 336     aout_filter.b_continuity = false;
 337
 338     in_buf.p_buffer = p_block->p_buffer;
 339     in_buf.i_nb_bytes = p_block->i_buffer;
 340     in_buf.i_nb_samples = p_block->i_samples;
 341     out_buf.p_buffer = p_out->p_buffer;
 342     out_buf.i_nb_bytes = p_out->i_buffer;
 343     out_buf.i_nb_samples = p_out->i_samples;
 344
 345     DoWork( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf );
 346
 347     block_Release( p_block );
 348
 349     p_out->i_buffer = out_buf.i_nb_bytes;
 350     p_out->i_samples = out_buf.i_nb_samples;
 351
 352     return p_out;
 353 }