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