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
, "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 if ( mlt_properties_get( properties
, "volume.limiter" ) != NULL
)
181 limiter_level
= mlt_properties_get_double( properties
, "volume.limiter" );
183 // Restore the original get_audio
184 frame
->get_audio
= mlt_properties_get_data( properties
, "volume.get_audio", NULL
);
186 // Get the producer's audio
187 mlt_frame_get_audio( frame
, buffer
, format
, frequency
, channels
, samples
);
188 //fprintf( stderr, "filter_volume: frequency %d\n", *frequency );
191 // Determine numeric limits
192 int bytes_per_samp
= (samp_width
- 1) / 8 + 1;
193 int samplemax
= (1 << (bytes_per_samp
* 8 - 1)) - 1;
194 int samplemin
= -samplemax
- 1;
198 int window
= mlt_properties_get_int( properties
, "volume.window" );
199 double *smooth_buffer
= mlt_properties_get_data( properties
, "volume.smooth_buffer", NULL
);
200 int *smooth_index
= mlt_properties_get_data( properties
, "volume.smooth_index", NULL
);
202 if ( window
> 0 && smooth_buffer
!= NULL
)
204 // Compute the signal power and put into smoothing buffer
205 smooth_buffer
[ *smooth_index
] = signal_max_power( *buffer
, *channels
, *samples
, &peak
);
206 // fprintf( stderr, "filter_volume: raw power %f ", smooth_buffer[ *smooth_index ] );
207 if ( smooth_buffer
[ *smooth_index
] > EPSILON
)
209 *smooth_index
= ( *smooth_index
+ 1 ) % window
;
211 // Smooth the data and compute the gain
212 //fprintf( stderr, "smoothed %f over %d frames\n", get_smoothed_data( smooth_buffer, window ), window );
213 gain
*= amplitude
/ get_smoothed_data( smooth_buffer
, window
);
218 gain
= amplitude
/ signal_max_power( *buffer
, *channels
, *samples
, &peak
);
222 // if ( gain > 1.0 && normalise )
223 // fprintf(stderr, "filter_volume: limiter level %f gain %f\n", limiter_level, gain );
225 if ( max_gain
> 0 && gain
> max_gain
)
229 for ( i
= 0; i
< ( *channels
* *samples
); i
++ )
231 sample
= (*buffer
)[i
] * gain
;
232 (*buffer
)[i
] = ROUND( sample
);
236 /* use limiter function instead of clipping */
238 (*buffer
)[i
] = ROUND( samplemax
* limiter( sample
/ (double) samplemax
, limiter_level
) );
240 /* perform clipping */
241 else if ( sample
> samplemax
)
242 (*buffer
)[i
] = samplemax
;
243 else if ( sample
< samplemin
)
244 (*buffer
)[i
] = samplemin
;
251 /** Filter processing.
254 static mlt_frame
filter_process( mlt_filter
this, mlt_frame frame
)
256 mlt_properties properties
= mlt_frame_properties( frame
);
257 mlt_properties filter_props
= mlt_filter_properties( this );
259 // Propogate the gain property
260 if ( mlt_properties_get( properties
, "gain" ) == NULL
)
262 double gain
= 1.0; // no adjustment
264 if ( mlt_properties_get( filter_props
, "gain" ) != NULL
)
266 char *p
= mlt_properties_get( filter_props
, "gain" );
268 if ( strncaseeq( p
, "normalise", 9 ) )
269 mlt_properties_set( filter_props
, "normalise", "" );
272 if ( strcmp( p
, "" ) != 0 )
273 gain
= fabs( strtod( p
, &p
) );
275 while ( isspace( *p
) )
278 /* check if "dB" is given after number */
279 if ( strncaseeq( p
, "db", 2 ) )
280 gain
= DBFSTOAMP( gain
);
283 mlt_properties_set_double( properties
, "gain", gain
);
286 // Propogate the maximum gain property
287 if ( mlt_properties_get( filter_props
, "max_gain" ) != NULL
)
289 char *p
= mlt_properties_get( filter_props
, "max_gain" );
290 double gain
= fabs( strtod( p
, &p
) ); // 0 = no max
292 while ( isspace( *p
) )
295 /* check if "dB" is given after number */
296 if ( strncaseeq( p
, "db", 2 ) )
297 gain
= DBFSTOAMP( gain
);
299 mlt_properties_set_double( properties
, "volume.max_gain", gain
);
302 // Parse and propogate the limiter property
303 if ( mlt_properties_get( filter_props
, "limiter" ) != NULL
)
305 char *p
= mlt_properties_get( filter_props
, "limiter" );
306 double level
= 0.5; /* -6dBFS */
307 if ( strcmp( p
, "" ) != 0 )
308 level
= strtod( p
, &p
);
310 while ( isspace( *p
) )
313 /* check if "dB" is given after number */
314 if ( strncaseeq( p
, "db", 2 ) )
318 level
= DBFSTOAMP( level
);
325 mlt_properties_set_double( properties
, "volume.limiter", level
);
328 // Parse and propogate the normalise property
329 if ( mlt_properties_get( filter_props
, "normalise" ) != NULL
)
331 char *p
= mlt_properties_get( filter_props
, "normalise" );
332 double amplitude
= 0.2511886431509580; /* -12dBFS */
333 if ( strcmp( p
, "" ) != 0 )
334 amplitude
= strtod( p
, &p
);
336 while ( isspace( *p
) )
339 /* check if "dB" is given after number */
340 if ( strncaseeq( p
, "db", 2 ) )
343 amplitude
= -amplitude
;
344 amplitude
= DBFSTOAMP( amplitude
);
349 amplitude
= -amplitude
;
350 if ( amplitude
> 1.0 )
353 mlt_properties_set_int( properties
, "volume.normalise", 1 );
354 mlt_properties_set_double( properties
, "volume.amplitude", amplitude
);
357 int window
= mlt_properties_get_int( filter_props
, "window" );
358 if ( mlt_properties_get( filter_props
, "smooth_buffer" ) == NULL
&& window
> 1 )
360 // Create a smoothing buffer for the calculated "max power" of frame of audio used in normalisation
361 double *smooth_buffer
= (double*) calloc( window
, sizeof( double ) );
363 for ( i
= 0; i
< window
; i
++ )
364 smooth_buffer
[ i
] = -1.0;
365 mlt_properties_set_data( filter_props
, "smooth_buffer", smooth_buffer
, 0, free
, NULL
);
366 int *smooth_index
= calloc( 1, sizeof( int ) );
368 mlt_properties_set_data( filter_props
, "smooth_index", smooth_index
, 0, free
, NULL
);
371 // Propogate the smoothing buffer properties
372 mlt_properties_set_int( properties
, "volume.window", window
);
373 mlt_properties_set_data( properties
, "volume.smooth_buffer",
374 mlt_properties_get_data( filter_props
, "smooth_buffer", NULL
), 0, NULL
, NULL
);
375 mlt_properties_set_data( properties
, "volume.smooth_index",
376 mlt_properties_get_data( filter_props
, "smooth_index", NULL
), 0, NULL
, NULL
);
378 // Backup the original get_audio (it's still needed)
379 mlt_properties_set_data( properties
, "volume.get_audio", frame
->get_audio
, 0, NULL
, NULL
);
381 // Override the get_audio method
382 frame
->get_audio
= filter_get_audio
;
387 /** Constructor for the filter.
390 mlt_filter
filter_volume_init( char *arg
)
392 mlt_filter
this = calloc( sizeof( struct mlt_filter_s
), 1 );
393 if ( this != NULL
&& mlt_filter_init( this, NULL
) == 0 )
395 mlt_properties properties
= mlt_filter_properties( this );
396 this->process
= filter_process
;
398 mlt_properties_set( properties
, "gain", arg
);
400 mlt_properties_set_int( properties
, "window", 75 );
401 mlt_properties_set( properties
, "max_gain", "20dB" );