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 "audio_output.h"
  33 #include "aout_internal.h"
  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
  45 static int  OpenFilter ( vlc_object_t * );
  46 static void CloseFilter( vlc_object_t * );
  47 static block_t *Resample( filter_t *, block_t * );
  48
  49 /*****************************************************************************
  50  * Local structures
  51  *****************************************************************************/
  52 struct filter_sys_t
  53 {
  54     int32_t *p_prev_sample;       /* this filter introduces a 1 sample delay */
  55
  56     unsigned int i_remainder;                /* remainder of previous sample */
  57
  58     audio_date_t end_date;
  59 };
  60
  61 /*****************************************************************************
  62  * Module descriptor
  63  *****************************************************************************/
  64 vlc_module_begin();
  65     set_description( _("Audio filter for linear interpolation resampling") );
  66     set_category( CAT_AUDIO );
  67     set_subcategory( SUBCAT_AUDIO_MISC );
  68     set_capability( "audio filter", 5 );
  69     set_callbacks( Create, Close );
  70
  71     add_submodule();
  72     set_description( _("Audio filter for linear interpolation resampling") );
  73     set_capability( "audio filter2", 5 );
  74     set_callbacks( OpenFilter, CloseFilter );
  75 vlc_module_end();
  76
  77 /*****************************************************************************
  78  * Create: allocate linear resampler
  79  *****************************************************************************/
  80 static int Create( vlc_object_t *p_this )
  81 {
  82     aout_filter_t * p_filter = (aout_filter_t *)p_this;
  83     struct filter_sys_t * p_sys;
  84
  85     if ( p_filter->input.i_rate == p_filter->output.i_rate
  86           || p_filter->input.i_format != p_filter->output.i_format
  87           || p_filter->input.i_physical_channels
  88               != p_filter->output.i_physical_channels
  89           || p_filter->input.i_original_channels
  90               != p_filter->output.i_original_channels
  91           || p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
  92     {
  93         return VLC_EGENERIC;
  94     }
  95
  96     /* Allocate the memory needed to store the module's structure */
  97     p_sys = malloc( sizeof(filter_sys_t) );
  98     p_filter->p_sys = (struct aout_filter_sys_t *)p_sys;
  99     if( p_sys == NULL )
 100     {
 101         msg_Err( p_filter, "out of memory" );
 102         return VLC_ENOMEM;
 103     }
 104     p_sys->p_prev_sample = malloc(
 105         aout_FormatNbChannels( &p_filter->input ) * sizeof(int32_t) );
 106     if( p_sys->p_prev_sample == NULL )
 107     {
 108         msg_Err( p_filter, "out of memory" );
 109         return VLC_ENOMEM;
 110     }
 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 = VLC_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 = aout_FormatNbChannels( &p_filter->input );
 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 = VLC_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     p_aout->p_libvlc->pf_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 = VLC_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     {
 276         msg_Err( p_filter, "out of memory" );
 277         return VLC_ENOMEM;
 278     }
 279
 280     p_sys->p_prev_sample = malloc(
 281         p_filter->fmt_in.audio.i_channels * sizeof(int32_t) );
 282     if( p_sys->p_prev_sample == NULL )
 283     {
 284         msg_Err( p_filter, "out of memory" );
 285         free( p_sys );
 286         return VLC_ENOMEM;
 287     }
 288
 289     p_filter->pf_audio_filter = Resample;
 290
 291     msg_Dbg( p_this, "%4.4s/%iKHz/%i->%4.4s/%iKHz/%i",
 292              (char *)&p_filter->fmt_in.i_codec,
 293              p_filter->fmt_in.audio.i_rate,
 294              p_filter->fmt_in.audio.i_channels,
 295              (char *)&p_filter->fmt_out.i_codec,
 296              p_filter->fmt_out.audio.i_rate,
 297              p_filter->fmt_out.audio.i_channels);
 298
 299     p_filter->fmt_out = p_filter->fmt_in;
 300     p_filter->fmt_out.audio.i_rate = i_out_rate;
 301
 302     return 0;
 303 }
 304
 305 /*****************************************************************************
 306  * CloseFilter : deallocate data structures
 307  *****************************************************************************/
 308 static void CloseFilter( vlc_object_t *p_this )
 309 {
 310     filter_t *p_filter = (filter_t *)p_this;
 311     free( p_filter->p_sys->p_prev_sample );
 312     free( p_filter->p_sys );
 313 }
 314
 315 /*****************************************************************************
 316  * Resample
 317  *****************************************************************************/
 318 static block_t *Resample( filter_t *p_filter, block_t *p_block )
 319 {
 320     aout_filter_t aout_filter;
 321     aout_buffer_t in_buf, out_buf;
 322     block_t *p_out;
 323     int i_out_size;
 324     int i_bytes_per_frame;
 325
 326     if( !p_block || !p_block->i_samples )
 327     {
 328         if( p_block ) p_block->pf_release( p_block );
 329         return NULL;
 330     }
 331
 332     i_bytes_per_frame = p_filter->fmt_out.audio.i_channels *
 333                   p_filter->fmt_out.audio.i_bitspersample / 8;
 334
 335     i_out_size = i_bytes_per_frame * ( 1 + (p_block->i_samples *
 336         p_filter->fmt_out.audio.i_rate / p_filter->fmt_in.audio.i_rate));
 337
 338     p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
 339     if( !p_out )
 340     {
 341         msg_Warn( p_filter, "can't get output buffer" );
 342         p_block->pf_release( p_block );
 343         return NULL;
 344     }
 345
 346     p_out->i_samples = i_out_size / i_bytes_per_frame;
 347     p_out->i_dts = p_block->i_dts;
 348     p_out->i_pts = p_block->i_pts;
 349     p_out->i_length = p_block->i_length;
 350
 351     aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
 352     aout_filter.input = p_filter->fmt_in.audio;
 353     aout_filter.output = p_filter->fmt_out.audio;
 354     aout_filter.b_continuity = VLC_FALSE;
 355
 356     in_buf.p_buffer = p_block->p_buffer;
 357     in_buf.i_nb_bytes = p_block->i_buffer;
 358     in_buf.i_nb_samples = p_block->i_samples;
 359     out_buf.p_buffer = p_out->p_buffer;
 360     out_buf.i_nb_bytes = p_out->i_buffer;
 361     out_buf.i_nb_samples = p_out->i_samples;
 362
 363     DoWork( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf );
 364
 365     p_block->pf_release( p_block );
 366
 367     p_out->i_buffer = out_buf.i_nb_bytes;
 368     p_out->i_samples = out_buf.i_nb_samples;
 369
 370     return p_out;
 371 }