modules/audio_filter/chorus_flanger.c

   1 /*****************************************************************************
   2  * chorus_flanger: Basic chorus/flanger/delay audio filter
   3  *****************************************************************************
   4  * Copyright (C) 2009-12 VLC authors and VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Srikanth Raju < srikiraju at gmail dot com >
   8  *          Sukrit Sangwan < sukritsangwan at gmail dot com >
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include <math.h>
  30
  31 #include <vlc_common.h>
  32 #include <vlc_plugin.h>
  33
  34 #include <vlc_aout.h>
  35 #include <vlc_filter.h>
  36
  37 /*****************************************************************************
  38  * Local prototypes
  39  *****************************************************************************/
  40
  41 typedef struct filter_sys_t filter_sys_t;
  42
  43 static int  Open     ( vlc_object_t * );
  44 static void Close    ( vlc_object_t * );
  45 static block_t *DoWork( filter_t *, block_t * );
  46 static int paramCallback( vlc_object_t *, char const *, vlc_value_t ,
  47                           vlc_value_t , void * );
  48 static int reallocate_buffer( filter_t *, filter_sys_t * );
  49
  50 struct filter_sys_t
  51 {
  52     /* TODO: Cleanup and optimise */
  53     int i_cumulative;
  54     int i_channels, i_sampleRate;
  55     float f_delayTime, f_feedbackGain;  /* delayTime is in milliseconds */
  56     float f_wetLevel, f_dryLevel;
  57     float f_sweepDepth, f_sweepRate;
  58
  59     float f_offset;
  60     int i_step;
  61     float f_temp;
  62     float f_sinMultiplier;
  63
  64     /* This data is for the the circular queue which stores the samples. */
  65     int i_bufferLength;
  66     float * p_delayLineStart, * p_delayLineEnd;
  67     float * p_write;
  68 };
  69
  70 /*****************************************************************************
  71  * Module descriptor
  72  *****************************************************************************/
  73
  74
  75 vlc_module_begin ()
  76     set_description( N_("Sound Delay") )
  77     set_shortname( N_("Delay") )
  78     set_help( N_("Add a delay effect to the sound") )
  79     set_category( CAT_AUDIO )
  80     set_subcategory( SUBCAT_AUDIO_AFILTER )
  81     add_shortcut( "delay" )
  82     add_float( "delay-time", 20, N_("Delay time"),
  83         N_("Time in milliseconds of the average delay. Note average"), true )
  84     add_float( "sweep-depth", 6, N_("Sweep Depth"),
  85         N_("Time in milliseconds of the maximum sweep depth. Thus, the sweep "
  86             "range will be delay-time +/- sweep-depth."), true )
  87     add_float( "sweep-rate", 6, N_("Sweep Rate"),
  88         N_("Rate of change of sweep depth in milliseconds shift per second "
  89            "of play"), true )
  90     add_float_with_range( "feedback-gain", 0.5, -0.9, 0.9,
  91         N_("Feedback gain"), N_("Gain on Feedback loop"), true )
  92     add_float_with_range( "wet-mix", 0.4, -0.999, 0.999,
  93         N_("Wet mix"), N_("Level of delayed signal"), true )
  94     add_float_with_range( "dry-mix", 0.4, -0.999, 0.999,
  95         N_("Dry Mix"), N_("Level of input signal"), true )
  96     set_capability( "audio filter", 0 )
  97     set_callbacks( Open, Close )
  98 vlc_module_end ()
  99
 100 /**
 101  * small_value: Helper function
 102  * return high pass cutoff
 103  */
 104 static inline float small_value(void)
 105 {
 106     /* allows for 2^-24, should be enough for 24-bit DACs at least */
 107     return 1.f / 16777216.f;
 108 }
 109
 110 /**
 111  * Open: initialize and create stuff
 112  * @param p_this
 113  */
 114 static int Open( vlc_object_t *p_this )
 115 {
 116     filter_t *p_filter = (filter_t*)p_this;
 117     filter_sys_t *p_sys = p_filter->p_sys = malloc( sizeof( *p_sys ) );
 118     if( !p_sys )
 119         return VLC_ENOMEM;
 120
 121     p_sys->i_channels       = aout_FormatNbChannels( &p_filter->fmt_in.audio );
 122     p_sys->f_delayTime      = var_CreateGetFloat( p_this, "delay-time" );
 123     p_sys->f_sweepDepth     = var_CreateGetFloat( p_this, "sweep-depth" );
 124     p_sys->f_sweepRate      = var_CreateGetFloat( p_this, "sweep-rate" );
 125     p_sys->f_feedbackGain   = var_CreateGetFloat( p_this, "feedback-gain" );
 126     p_sys->f_dryLevel       = var_CreateGetFloat( p_this, "dry-mix" );
 127     p_sys->f_wetLevel       = var_CreateGetFloat( p_this, "wet-mix" );
 128     var_AddCallback( p_this, "delay-time", paramCallback, p_sys );
 129     var_AddCallback( p_this, "sweep-depth", paramCallback, p_sys );
 130     var_AddCallback( p_this, "sweep-rate", paramCallback, p_sys );
 131     var_AddCallback( p_this, "feedback-gain", paramCallback, p_sys );
 132     var_AddCallback( p_this, "dry-mix", paramCallback, p_sys );
 133     var_AddCallback( p_this, "wet-mix", paramCallback, p_sys );
 134
 135     if( p_sys->f_delayTime < 0.f )
 136     {
 137         msg_Err( p_filter, "Delay Time is invalid" );
 138         free(p_sys);
 139         return VLC_EGENERIC;
 140     }
 141
 142     if( p_sys->f_sweepDepth > p_sys->f_delayTime || p_sys->f_sweepDepth < 0.f )
 143     {
 144         msg_Err( p_filter, "Sweep Depth is invalid" );
 145         free( p_sys );
 146         return VLC_EGENERIC;
 147     }
 148
 149     if( p_sys->f_sweepRate < 0.f )
 150     {
 151         msg_Err( p_filter, "Sweep Rate is invalid" );
 152         free( p_sys );
 153         return VLC_EGENERIC;
 154     }
 155
 156     /* Max delay = delay + depth. Min = delay - depth */
 157     p_sys->i_bufferLength = p_sys->i_channels * ( (int)( ( p_sys->f_delayTime
 158                 + p_sys->f_sweepDepth ) * p_filter->fmt_in.audio.i_rate/1000 ) + 1 );
 159
 160     msg_Dbg( p_filter , "Buffer length:%d, Channels:%d, Sweep Depth:%f, Delay "
 161              "time:%f, Sweep Rate:%f, Sample Rate: %d", p_sys->i_bufferLength,
 162              p_sys->i_channels, (double) p_sys->f_sweepDepth,
 163              (double) p_sys->f_delayTime, (double) p_sys->f_sweepRate,
 164              p_filter->fmt_in.audio.i_rate );
 165     if( p_sys->i_bufferLength <= 0 )
 166     {
 167         msg_Err( p_filter, "Delay-time, Sample rate or Channels was incorrect" );
 168         free(p_sys);
 169         return VLC_EGENERIC;
 170     }
 171
 172     p_sys->p_delayLineStart = calloc( p_sys->i_bufferLength, sizeof( float ) );
 173     if( !p_sys->p_delayLineStart )
 174     {
 175         free( p_sys );
 176         return VLC_ENOMEM;
 177     }
 178
 179     p_sys->i_cumulative = 0;
 180     p_sys->i_step = p_sys->f_sweepRate > 0 ? 1 : 0;
 181     p_sys->f_offset = 0;
 182     p_sys->f_temp = 0;
 183
 184     p_sys->p_delayLineEnd = p_sys->p_delayLineStart + p_sys->i_bufferLength;
 185     p_sys->p_write = p_sys->p_delayLineStart;
 186
 187     if( p_sys->f_sweepDepth < small_value() ||
 188             p_filter->fmt_in.audio.i_rate < small_value() ) {
 189         p_sys->f_sinMultiplier = 0.f;
 190     }
 191     else {
 192         p_sys->f_sinMultiplier = 11 * p_sys->f_sweepRate /
 193             ( 7 * p_sys->f_sweepDepth * p_filter->fmt_in.audio.i_rate ) ;
 194     }
 195     p_sys->i_sampleRate = p_filter->fmt_in.audio.i_rate;
 196
 197     p_filter->fmt_in.audio.i_format = VLC_CODEC_FL32;
 198     aout_FormatPrepare(&p_filter->fmt_in.audio);
 199     p_filter->fmt_out.audio = p_filter->fmt_in.audio;
 200     p_filter->pf_audio_filter = DoWork;
 201
 202     return VLC_SUCCESS;
 203 }
 204
 205 /**
 206  * sanitize: Helper function to eliminate small amplitudes
 207  * @param f_value pointer to value to clean
 208  */
 209 static inline void sanitize( float * f_value )
 210 {
 211     if ( fabsf( *f_value ) < small_value() )
 212         *f_value = 0.f;
 213 }
 214
 215
 216 /**
 217  * DoWork : delays and finds the value of the current frame
 218  * @param p_filter This filter object
 219  * @param p_in_buf Input buffer
 220  * @return Output buffer
 221  */
 222 static block_t *DoWork( filter_t *p_filter, block_t *p_in_buf )
 223 {
 224     struct filter_sys_t *p_sys = p_filter->p_sys;
 225     int i_chan;
 226     unsigned i_samples = p_in_buf->i_nb_samples; /* number of samples */
 227     /* maximum number of samples to offset in buffer */
 228     int i_maxOffset = floorf( p_sys->f_sweepDepth * p_sys->i_sampleRate / 1000 );
 229     float *p_out = (float*)p_in_buf->p_buffer;
 230     float *p_in =  (float*)p_in_buf->p_buffer;
 231
 232     float *p_ptr, f_temp = 0;/* f_diff = 0, f_frac = 0;*/
 233
 234     /* Process each sample */
 235     for( unsigned i = 0; i < i_samples ; i++ )
 236     {
 237         /* Sine function as a oscillator wave to calculate sweep */
 238         p_sys->i_cumulative += p_sys->i_step;
 239         p_sys->f_offset = sinf( (p_sys->i_cumulative) * p_sys->f_sinMultiplier )
 240                 * floorf(p_sys->f_sweepDepth * p_sys->i_sampleRate / 1000);
 241         if( abs( p_sys->i_step ) > 0 )
 242         {
 243             if( p_sys->i_cumulative >=  floorf( p_sys->f_sweepDepth *
 244                         p_sys->i_sampleRate / p_sys->f_sweepRate ))
 245             {
 246                 p_sys->f_offset = i_maxOffset;
 247                 p_sys->i_step = -1 * ( p_sys->i_step );
 248             }
 249             if( p_sys->i_cumulative <= floorf( -1 * p_sys->f_sweepDepth *
 250                         p_sys->i_sampleRate / p_sys->f_sweepRate ) )
 251             {
 252                 p_sys->f_offset = -i_maxOffset;
 253                 p_sys->i_step = -1 * ( p_sys->i_step );
 254             }
 255         }
 256         /* Calculate position in delay */
 257         int offset = floorf( p_sys->f_offset );
 258         p_ptr = p_sys->p_write + ( i_maxOffset - offset ) * p_sys->i_channels;
 259
 260         /* Handle Overflow */
 261         if( p_ptr < p_sys->p_delayLineStart )
 262         {
 263             p_ptr += p_sys->i_bufferLength - p_sys->i_channels;
 264         }
 265         if( p_ptr > p_sys->p_delayLineEnd - 2*p_sys->i_channels )
 266         {
 267             p_ptr -= p_sys->i_bufferLength - p_sys->i_channels;
 268         }
 269         /* For interpolation */
 270 /*        f_frac = ( p_sys->f_offset - (int)p_sys->f_offset );*/
 271         for( i_chan = 0; i_chan < p_sys->i_channels; i_chan++ )
 272         {
 273 /*            if( p_ptr <= p_sys->p_delayLineStart + p_sys->i_channels )
 274                 f_diff = *(p_sys->p_delayLineEnd + i_chan) - p_ptr[i_chan];
 275             else
 276                 f_diff = *( p_ptr - p_sys->i_channels + i_chan )
 277                             - p_ptr[i_chan];*/
 278             f_temp = ( *( p_ptr + i_chan ) );//+ f_diff * f_frac;
 279             /*Linear Interpolation. FIXME. This creates LOTS of noise */
 280             sanitize(&f_temp);
 281             p_out[i_chan] = p_sys->f_dryLevel * p_in[i_chan] +
 282                 p_sys->f_wetLevel * f_temp;
 283             *( p_sys->p_write + i_chan ) = p_in[i_chan] +
 284                 p_sys->f_feedbackGain * f_temp;
 285         }
 286         if( p_sys->p_write == p_sys->p_delayLineStart )
 287             for( i_chan = 0; i_chan < p_sys->i_channels; i_chan++ )
 288                 *( p_sys->p_delayLineEnd - p_sys->i_channels + i_chan )
 289                     = *( p_sys->p_delayLineStart + i_chan );
 290
 291         p_in += p_sys->i_channels;
 292         p_out += p_sys->i_channels;
 293         p_sys->p_write += p_sys->i_channels;
 294         if( p_sys->p_write == p_sys->p_delayLineEnd - p_sys->i_channels )
 295         {
 296             p_sys->p_write = p_sys->p_delayLineStart;
 297         }
 298
 299     }
 300     return p_in_buf;
 301 }
 302
 303 /**
 304  * Close: Destructor
 305  * @param p_this pointer to this filter object
 306  */
 307 static void Close( vlc_object_t *p_this )
 308 {
 309     filter_t *p_filter = ( filter_t* )p_this;
 310     filter_sys_t *p_sys = p_filter->p_sys;
 311
 312     var_DelCallback( p_this, "delay-time", paramCallback, p_sys );
 313     var_DelCallback( p_this, "sweep-depth", paramCallback, p_sys );
 314     var_DelCallback( p_this, "sweep-rate", paramCallback, p_sys );
 315     var_DelCallback( p_this, "feedback-gain", paramCallback, p_sys );
 316     var_DelCallback( p_this, "wet-mix", paramCallback, p_sys );
 317     var_DelCallback( p_this, "dry-mix", paramCallback, p_sys );
 318     var_Destroy( p_this, "delay-time" );
 319     var_Destroy( p_this, "sweep-depth" );
 320     var_Destroy( p_this, "sweep-rate" );
 321     var_Destroy( p_this, "feedback-gain" );
 322     var_Destroy( p_this, "wet-mix" );
 323     var_Destroy( p_this, "dry-mix" );
 324
 325     free( p_sys->p_delayLineStart );
 326     free( p_sys );
 327 }
 328
 329 /******************************************************************************
 330  * Callback to update parameters on the fly
 331  ******************************************************************************/
 332 static int paramCallback( vlc_object_t *p_this, char const *psz_var,
 333                           vlc_value_t oldval, vlc_value_t newval, void *p_data )
 334 {
 335     filter_t *p_filter = (filter_t *)p_this;
 336     filter_sys_t *p_sys = (filter_sys_t *) p_data;
 337
 338     if( !strncmp( psz_var, "delay-time", 10 ) )
 339     {
 340         /* if invalid value pretend everything is OK without updating value */
 341         if( newval.f_float < 0 )
 342             return VLC_SUCCESS;
 343         p_sys->f_delayTime = newval.f_float;
 344         if( !reallocate_buffer( p_filter, p_sys ) )
 345         {
 346             p_sys->f_delayTime = oldval.f_float;
 347             p_sys->i_bufferLength = p_sys->i_channels * ( (int)
 348                             ( ( p_sys->f_delayTime + p_sys->f_sweepDepth ) *
 349                               p_filter->fmt_in.audio.i_rate/1000 ) + 1 );
 350         }
 351     }
 352     else if( !strncmp( psz_var, "sweep-depth", 11 ) )
 353     {
 354         if( newval.f_float < 0 || newval.f_float > p_sys->f_delayTime)
 355             return VLC_SUCCESS;
 356         p_sys->f_sweepDepth = newval.f_float;
 357         if( !reallocate_buffer( p_filter, p_sys ) )
 358         {
 359             p_sys->f_sweepDepth = oldval.f_float;
 360             p_sys->i_bufferLength = p_sys->i_channels * ( (int)
 361                             ( ( p_sys->f_delayTime + p_sys->f_sweepDepth ) *
 362                               p_filter->fmt_in.audio.i_rate/1000 ) + 1 );
 363         }
 364     }
 365     else if( !strncmp( psz_var, "sweep-rate", 10 ) )
 366     {
 367         if( newval.f_float > p_sys->f_sweepDepth )
 368             return VLC_SUCCESS;
 369         p_sys->f_sweepRate = newval.f_float;
 370         /* Calculate new f_sinMultiplier */
 371         if( p_sys->f_sweepDepth < small_value() ||
 372                 p_filter->fmt_in.audio.i_rate < small_value() ) {
 373             p_sys->f_sinMultiplier = 0.0;
 374         }
 375         else {
 376             p_sys->f_sinMultiplier = 11 * p_sys->f_sweepRate /
 377                 ( 7 * p_sys->f_sweepDepth * p_filter->fmt_in.audio.i_rate ) ;
 378         }
 379     }
 380     else if( !strncmp( psz_var, "feedback-gain", 13 ) )
 381         p_sys->f_feedbackGain = newval.f_float;
 382     else if( !strncmp( psz_var, "wet-mix", 7 ) )
 383         p_sys->f_wetLevel = newval.f_float;
 384     else if( !strncmp( psz_var, "dry-mix", 7 ) )
 385         p_sys->f_dryLevel = newval.f_float;
 386
 387     return VLC_SUCCESS;
 388 }
 389
 390 static int reallocate_buffer( filter_t *p_filter,  filter_sys_t *p_sys )
 391 {
 392     p_sys->i_bufferLength = p_sys->i_channels * ( (int)( ( p_sys->f_delayTime
 393            + p_sys->f_sweepDepth ) * p_filter->fmt_in.audio.i_rate/1000 ) + 1 );
 394
 395     float *temp = realloc( p_sys->p_delayLineStart, p_sys->i_bufferLength );
 396     if( unlikely( !temp ) )
 397     {
 398         msg_Err( p_filter, "Couldnt reallocate buffer for new delay." );
 399         return 0;
 400     }
 401     p_sys->p_delayLineStart = temp;
 402     p_sys->p_delayLineEnd = p_sys->p_delayLineStart + p_sys->i_bufferLength;
 403     return 1;
 404 }