2 * filter_volume.c -- adjust audio volume
3 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
4 * Author: Dan Dennedy <dan@dennedy.org>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software Foundation,
18 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 #include "filter_volume.h"
23 #include <framework/mlt_frame.h>
31 #define MAX_CHANNELS 6
32 #define EPSILON 0.00001
34 /* The normalise functions come from the normalize utility:
35 Copyright (C) 1999--2002 Chris Vaill */
40 # define ROUND(x) floor((x) + 0.5)
43 #define DBFSTOAMP(x) pow(10,(x)/20.0)
45 /** Return nonzero if the two strings are equal, ignoring case, up to
46 the first n characters.
48 int strncaseeq(const char *s1
, const char *s2
, size_t n
)
52 if (tolower(*s1
++) != tolower(*s2
++))
60 / tanh((x + lev) / (1-lev)) * (1-lev) - lev (for x < -lev)
62 x' = | x (for |x| <= lev)
64 \ tanh((x - lev) / (1-lev)) * (1-lev) + lev (for x > lev)
66 With limiter level = 0, this is equivalent to a tanh() function;
67 with limiter level = 1, this is equivalent to clipping.
69 static inline double limiter( double x
, double lmtr_lvl
)
74 xp
= tanh((x
+ lmtr_lvl
) / (1-lmtr_lvl
)) * (1-lmtr_lvl
) - lmtr_lvl
;
75 else if (x
> lmtr_lvl
)
76 xp
= tanh((x
- lmtr_lvl
) / (1-lmtr_lvl
)) * (1-lmtr_lvl
) + lmtr_lvl
;
79 // fprintf( stderr, "filter_volume: sample %f limited %f\n", x, xp );
85 /** Takes a full smoothing window, and returns the value of the center
88 Currently, just does a mean filter, but we could do a median or
89 gaussian filter here instead.
91 static inline double get_smoothed_data( double *buf
, int count
)
96 for ( i
= 0, j
= 0; i
< count
; i
++ )
98 if ( buf
[ i
] != -1.0 )
100 smoothed
+= buf
[ i
];
105 // fprintf( stderr, "smoothed over %d values, result %f\n", j, smoothed );
110 /** Get the max power level (using RMS) and peak level of the audio segment.
112 double signal_max_power( int16_t *buffer
, int channels
, int samples
, int16_t *peak
)
114 // Determine numeric limits
115 int bytes_per_samp
= (samp_width
- 1) / 8 + 1;
116 int16_t max
= (1 << (bytes_per_samp
* 8 - 1)) - 1;
117 int16_t min
= -max
- 1;
119 double *sums
= (double *) calloc( channels
, sizeof(double) );
122 double pow
, maxpow
= 0;
124 /* initialize peaks to effectively -inf and +inf */
125 int16_t max_sample
= min
;
126 int16_t min_sample
= max
;
128 for ( i
= 0; i
< samples
; i
++ )
130 for ( c
= 0; c
< channels
; c
++ )
133 sums
[ c
] += (double) sample
* (double) sample
;
136 if ( sample
> max_sample
)
138 else if ( sample
< min_sample
)
142 for ( c
= 0; c
< channels
; c
++ )
144 pow
= sums
[ c
] / (double) samples
;
151 /* scale the pow value to be in the range 0.0 -- 1.0 */
152 maxpow
/= ( (double) min
* (double) min
);
154 if ( -min_sample
> max_sample
)
155 *peak
= min_sample
/ (double) min
;
157 *peak
= max_sample
/ (double) max
;
159 return sqrt( maxpow
);
162 /* ------ End normalize functions --------------------------------------- */
167 static int filter_get_audio( mlt_frame frame
, int16_t **buffer
, mlt_audio_format
*format
, int *frequency
, int *channels
, int *samples
)
169 // Get the properties of the a frame
170 mlt_properties properties
= mlt_frame_properties( frame
);
171 double gain
= mlt_properties_get_double( properties
, "volume.gain" );
172 double max_gain
= mlt_properties_get_double( properties
, "volume.max_gain" );
173 double limiter_level
= 0.5; /* -6 dBFS */
174 int normalise
= mlt_properties_get_int( properties
, "volume.normalise" );
175 double amplitude
= mlt_properties_get_double( properties
, "volume.amplitude" );
180 // Get the filter from the frame
181 mlt_filter
this = mlt_properties_get_data( properties
, "filter_volume", NULL
);
183 // Get the properties from the filter
184 mlt_properties filter_props
= mlt_filter_properties( this );
186 if ( mlt_properties_get( properties
, "volume.limiter" ) != NULL
)
187 limiter_level
= mlt_properties_get_double( properties
, "volume.limiter" );
189 // Restore the original get_audio
190 frame
->get_audio
= mlt_properties_get_data( properties
, "volume.get_audio", NULL
);
192 // Get the producer's audio
193 mlt_frame_get_audio( frame
, buffer
, format
, frequency
, channels
, samples
);
194 // fprintf( stderr, "filter_volume: frequency %d\n", *frequency );
196 // Determine numeric limits
197 int bytes_per_samp
= (samp_width
- 1) / 8 + 1;
198 int samplemax
= (1 << (bytes_per_samp
* 8 - 1)) - 1;
199 int samplemin
= -samplemax
- 1;
203 int window
= mlt_properties_get_int( filter_props
, "window" );
204 double *smooth_buffer
= mlt_properties_get_data( filter_props
, "smooth_buffer", NULL
);
205 int *smooth_index
= mlt_properties_get_data( filter_props
, "smooth_index", NULL
);
207 if ( window
> 0 && smooth_buffer
!= NULL
)
209 // Compute the signal power and put into smoothing buffer
210 smooth_buffer
[ *smooth_index
] = signal_max_power( *buffer
, *channels
, *samples
, &peak
);
211 // fprintf( stderr, "filter_volume: raw power %f ", smooth_buffer[ *smooth_index ] );
212 if ( smooth_buffer
[ *smooth_index
] > EPSILON
)
214 *smooth_index
= ( *smooth_index
+ 1 ) % window
;
216 // Smooth the data and compute the gain
217 // fprintf( stderr, "smoothed %f over %d frames\n", get_smoothed_data( smooth_buffer, window ), window );
218 gain
*= amplitude
/ get_smoothed_data( smooth_buffer
, window
);
223 gain
*= amplitude
/ signal_max_power( *buffer
, *channels
, *samples
, &peak
);
227 // if ( gain > 1.0 && normalise )
228 // fprintf(stderr, "filter_volume: limiter level %f gain %f\n", limiter_level, gain );
230 if ( max_gain
> 0 && gain
> max_gain
)
233 // Initialise filter's previous gain value to prevent an inadvertant jump from 0
234 if ( mlt_properties_get( filter_props
, "previous_gain" ) == NULL
)
235 mlt_properties_set_double( filter_props
, "previous_gain", gain
);
237 // Start the gain out at the previous
238 double previous_gain
= mlt_properties_get_double( filter_props
, "previous_gain" );
240 // Determine ramp increment
241 double gain_step
= ( gain
- previous_gain
) / *samples
;
242 // fprintf( stderr, "filter_volume: previous gain %f current gain %f step %f\n", previous_gain, gain, gain_step );
244 // Save the current gain for the next iteration
245 mlt_properties_set_double( filter_props
, "previous_gain", gain
);
247 // Ramp from the previous gain to the current
248 gain
= previous_gain
;
250 int16_t *p
= *buffer
;
253 for ( i
= 0; i
< *samples
; i
++ )
255 for ( j
= 0; j
< *channels
; j
++ )
258 *p
= ROUND( sample
);
262 /* use limiter function instead of clipping */
264 *p
= ROUND( samplemax
* limiter( sample
/ (double) samplemax
, limiter_level
) );
266 /* perform clipping */
267 else if ( sample
> samplemax
)
269 else if ( sample
< samplemin
)
280 /** Filter processing.
283 static mlt_frame
filter_process( mlt_filter
this, mlt_frame frame
)
285 mlt_properties properties
= mlt_frame_properties( frame
);
286 mlt_properties filter_props
= mlt_filter_properties( this );
288 // Parse the gain property
289 if ( mlt_properties_get( properties
, "gain" ) == NULL
)
291 double gain
= 1.0; // no adjustment
293 if ( mlt_properties_get( filter_props
, "gain" ) != NULL
)
295 char *p
= mlt_properties_get( filter_props
, "gain" );
297 if ( strncaseeq( p
, "normalise", 9 ) )
298 mlt_properties_set( filter_props
, "normalise", "" );
301 if ( strcmp( p
, "" ) != 0 )
302 gain
= fabs( strtod( p
, &p
) );
304 while ( isspace( *p
) )
307 /* check if "dB" is given after number */
308 if ( strncaseeq( p
, "db", 2 ) )
309 gain
= DBFSTOAMP( gain
);
311 // If there is an end adjust gain to the range
312 if ( mlt_properties_get( filter_props
, "end" ) != NULL
)
314 // Determine the time position of this frame in the transition duration
315 mlt_position in
= mlt_filter_get_in( this );
316 mlt_position out
= mlt_filter_get_out( this );
317 mlt_position time
= mlt_frame_get_position( frame
);
318 double position
= ( double )( time
- in
) / ( double )( out
- in
+ 1 );
321 char *p
= mlt_properties_get( filter_props
, "end" );
322 if ( strcmp( p
, "" ) != 0 )
323 end
= fabs( strtod( p
, &p
) );
325 while ( isspace( *p
) )
328 /* check if "dB" is given after number */
329 if ( strncaseeq( p
, "db", 2 ) )
330 end
= DBFSTOAMP( gain
);
333 gain
+= ( end
- gain
) * position
;
337 mlt_properties_set_double( properties
, "volume.gain", gain
);
340 // Parse the maximum gain property
341 if ( mlt_properties_get( filter_props
, "max_gain" ) != NULL
)
343 char *p
= mlt_properties_get( filter_props
, "max_gain" );
344 double gain
= fabs( strtod( p
, &p
) ); // 0 = no max
346 while ( isspace( *p
) )
349 /* check if "dB" is given after number */
350 if ( strncaseeq( p
, "db", 2 ) )
351 gain
= DBFSTOAMP( gain
);
353 mlt_properties_set_double( properties
, "volume.max_gain", gain
);
356 // Parse the limiter property
357 if ( mlt_properties_get( filter_props
, "limiter" ) != NULL
)
359 char *p
= mlt_properties_get( filter_props
, "limiter" );
360 double level
= 0.5; /* -6dBFS */
361 if ( strcmp( p
, "" ) != 0 )
362 level
= strtod( p
, &p
);
364 while ( isspace( *p
) )
367 /* check if "dB" is given after number */
368 if ( strncaseeq( p
, "db", 2 ) )
372 level
= DBFSTOAMP( level
);
379 mlt_properties_set_double( properties
, "volume.limiter", level
);
382 // Parse the normalise property
383 if ( mlt_properties_get( filter_props
, "normalise" ) != NULL
)
385 char *p
= mlt_properties_get( filter_props
, "normalise" );
386 double amplitude
= 0.2511886431509580; /* -12dBFS */
387 if ( strcmp( p
, "" ) != 0 )
388 amplitude
= strtod( p
, &p
);
390 while ( isspace( *p
) )
393 /* check if "dB" is given after number */
394 if ( strncaseeq( p
, "db", 2 ) )
397 amplitude
= -amplitude
;
398 amplitude
= DBFSTOAMP( amplitude
);
403 amplitude
= -amplitude
;
404 if ( amplitude
> 1.0 )
408 // If there is an end adjust gain to the range
409 if ( mlt_properties_get( filter_props
, "end" ) != NULL
)
411 // Determine the time position of this frame in the transition duration
412 mlt_position in
= mlt_filter_get_in( this );
413 mlt_position out
= mlt_filter_get_out( this );
414 mlt_position time
= mlt_frame_get_position( frame
);
415 double position
= ( double )( time
- in
) / ( double )( out
- in
+ 1 );
416 amplitude
*= position
;
418 mlt_properties_set_int( properties
, "volume.normalise", 1 );
419 mlt_properties_set_double( properties
, "volume.amplitude", amplitude
);
422 // Parse the window property and allocate smoothing buffer if needed
423 int window
= mlt_properties_get_int( filter_props
, "window" );
424 if ( mlt_properties_get( filter_props
, "smooth_buffer" ) == NULL
&& window
> 1 )
426 // Create a smoothing buffer for the calculated "max power" of frame of audio used in normalisation
427 double *smooth_buffer
= (double*) calloc( window
, sizeof( double ) );
429 for ( i
= 0; i
< window
; i
++ )
430 smooth_buffer
[ i
] = -1.0;
431 mlt_properties_set_data( filter_props
, "smooth_buffer", smooth_buffer
, 0, free
, NULL
);
432 int *smooth_index
= calloc( 1, sizeof( int ) );
434 mlt_properties_set_data( filter_props
, "smooth_index", smooth_index
, 0, free
, NULL
);
437 // Put a filter reference onto the frame
438 mlt_properties_set_data( properties
, "filter_volume", this, 0, NULL
, NULL
);
440 // Backup the original get_audio (it's still needed)
441 mlt_properties_set_data( properties
, "volume.get_audio", frame
->get_audio
, 0, NULL
, NULL
);
443 // Override the get_audio method
444 frame
->get_audio
= filter_get_audio
;
449 /** Constructor for the filter.
452 mlt_filter
filter_volume_init( char *arg
)
454 mlt_filter
this = calloc( sizeof( struct mlt_filter_s
), 1 );
455 if ( this != NULL
&& mlt_filter_init( this, NULL
) == 0 )
457 mlt_properties properties
= mlt_filter_properties( this );
458 this->process
= filter_process
;
460 mlt_properties_set( properties
, "gain", arg
);
462 mlt_properties_set_int( properties
, "window", 75 );
463 mlt_properties_set( properties
, "max_gain", "20dB" );