git.sesse.net Git - mlt/blob - src/modules/core/transition_mix.c

   1 /*
   2  * transition_mix.c -- mix two audio streams
   3  * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
   4  * Author: Dan Dennedy <dan@dennedy.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <framework/mlt_transition.h>
  22 #include <framework/mlt_frame.h>
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <math.h>
  28
  29
  30 static int mix_audio( mlt_frame this, mlt_frame that, float weight_start, float weight_end, void **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
  31 {
  32         int ret = 0;
  33         int16_t *src, *dest;
  34         int frequency_src = *frequency, frequency_dest = *frequency;
  35         int channels_src = *channels, channels_dest = *channels;
  36         int samples_src = *samples, samples_dest = *samples;
  37         int i, j;
  38         double d = 0, s = 0;
  39
  40         mlt_frame_get_audio( that, (void**) &src, format, &frequency_src, &channels_src, &samples_src );
  41         mlt_frame_get_audio( this, (void**) &dest, format, &frequency_dest, &channels_dest, &samples_dest );
  42
  43         int silent = mlt_properties_get_int( MLT_FRAME_PROPERTIES( this ), "silent_audio" );
  44         mlt_properties_set_int( MLT_FRAME_PROPERTIES( this ), "silent_audio", 0 );
  45         if ( silent )
  46                 memset( dest, 0, samples_dest * channels_dest * sizeof( int16_t ) );
  47
  48         silent = mlt_properties_get_int( MLT_FRAME_PROPERTIES( that ), "silent_audio" );
  49         mlt_properties_set_int( MLT_FRAME_PROPERTIES( that ), "silent_audio", 0 );
  50         if ( silent )
  51                 memset( src, 0, samples_src * channels_src * sizeof( int16_t ) );
  52
  53         if ( channels_src > 6 )
  54                 channels_src = 0;
  55         if ( channels_dest > 6 )
  56                 channels_dest = 0;
  57         if ( samples_src > 4000 )
  58                 samples_src = 0;
  59         if ( samples_dest > 4000 )
  60                 samples_dest = 0;
  61
  62         // determine number of samples to process
  63         *samples = samples_src < samples_dest ? samples_src : samples_dest;
  64         *channels = channels_src < channels_dest ? channels_src : channels_dest;
  65         *buffer = dest;
  66         *frequency = frequency_dest;
  67
  68         // Compute a smooth ramp over start to end
  69         float weight = weight_start;
  70         float weight_step = ( weight_end - weight_start ) / *samples;
  71
  72         if ( src == dest )
  73         {
  74                 *samples = samples_src;
  75                 *channels = channels_src;
  76                 *buffer = src;
  77                 *frequency = frequency_src;
  78                 return ret;
  79         }
  80
  81         // Mixdown
  82         for ( i = 0; i < *samples; i++ )
  83         {
  84                 for ( j = 0; j < *channels; j++ )
  85                 {
  86                         if ( j < channels_dest )
  87                                 d = (double) dest[ i * channels_dest + j ];
  88                         if ( j < channels_src )
  89                                 s = (double) src[ i * channels_src + j ];
  90                         dest[ i * channels_dest + j ] = s * weight + d * ( 1.0 - weight );
  91                 }
  92                 weight += weight_step;
  93         }
  94
  95         return ret;
  96 }
  97
  98 // Replacement for broken mlt_frame_audio_mix - this filter uses an inline low pass filter
  99 // to allow mixing without volume hacking
 100 static int combine_audio( mlt_frame this, mlt_frame that, void **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 101 {
 102         int ret = 0;
 103         int16_t *src, *dest;
 104         int frequency_src = *frequency, frequency_dest = *frequency;
 105         int channels_src = *channels, channels_dest = *channels;
 106         int samples_src = *samples, samples_dest = *samples;
 107         int i, j;
 108         double vp[ 6 ];
 109         double b_weight = 1.0;
 110
 111         if ( mlt_properties_get_int( MLT_FRAME_PROPERTIES( this ), "meta.mixdown" ) )
 112                 b_weight = 1.0 - mlt_properties_get_double( MLT_FRAME_PROPERTIES( this ), "meta.volume" );
 113
 114         mlt_frame_get_audio( that, (void**) &src, format, &frequency_src, &channels_src, &samples_src );
 115         mlt_frame_get_audio( this, (void**) &dest, format, &frequency_dest, &channels_dest, &samples_dest );
 116
 117         int silent = mlt_properties_get_int( MLT_FRAME_PROPERTIES( this ), "silent_audio" );
 118         mlt_properties_set_int( MLT_FRAME_PROPERTIES( this ), "silent_audio", 0 );
 119         if ( silent )
 120                 memset( dest, 0, samples_dest * channels_dest * sizeof( int16_t ) );
 121
 122         silent = mlt_properties_get_int( MLT_FRAME_PROPERTIES( that ), "silent_audio" );
 123         mlt_properties_set_int( MLT_FRAME_PROPERTIES( that ), "silent_audio", 0 );
 124         if ( silent )
 125                 memset( src, 0, samples_src * channels_src * sizeof( int16_t ) );
 126
 127         if ( src == dest )
 128         {
 129                 *samples = samples_src;
 130                 *channels = channels_src;
 131                 *buffer = src;
 132                 *frequency = frequency_src;
 133                 return ret;
 134         }
 135
 136         // determine number of samples to process
 137         *samples = samples_src < samples_dest ? samples_src : samples_dest;
 138         *channels = channels_src < channels_dest ? channels_src : channels_dest;
 139         *buffer = dest;
 140         *frequency = frequency_dest;
 141
 142         for ( j = 0; j < *channels; j++ )
 143                 vp[ j ] = ( double )dest[ j ];
 144
 145         double Fc = 0.5;
 146         double B = exp(-2.0 * M_PI * Fc);
 147         double A = 1.0 - B;
 148         double v;
 149
 150         for ( i = 0; i < *samples; i++ )
 151         {
 152                 for ( j = 0; j < *channels; j++ )
 153                 {
 154                         v = ( double )( b_weight * dest[ i * channels_dest + j ] + src[ i * channels_src + j ] );
 155                         v = v < -32767 ? -32767 : v > 32768 ? 32768 : v;
 156                         vp[ j ] = dest[ i * channels_dest + j ] = ( int16_t )( v * A + vp[ j ] * B );
 157                 }
 158         }
 159
 160         return ret;
 161 }
 162
 163 /** Get the audio.
 164 */
 165
 166 static int transition_get_audio( mlt_frame frame, void **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
 167 {
 168         // Get the b frame from the stack
 169         mlt_frame b_frame = mlt_frame_pop_audio( frame );
 170
 171         // Get the effect
 172         mlt_transition effect = mlt_frame_pop_audio( frame );
 173
 174         // Get the properties of the b frame
 175         mlt_properties b_props = MLT_FRAME_PROPERTIES( b_frame );
 176
 177         // We can only mix s16
 178         *format = mlt_audio_s16;
 179
 180         if ( mlt_properties_get_int( MLT_TRANSITION_PROPERTIES( effect ), "combine" ) == 0 )
 181         {
 182                 double mix_start = 0.5, mix_end = 0.5;
 183                 if ( mlt_properties_get( b_props, "audio.previous_mix" ) != NULL )
 184                         mix_start = mlt_properties_get_double( b_props, "audio.previous_mix" );
 185                 if ( mlt_properties_get( b_props, "audio.mix" ) != NULL )
 186                         mix_end = mlt_properties_get_double( b_props, "audio.mix" );
 187                 if ( mlt_properties_get_int( b_props, "audio.reverse" ) )
 188                 {
 189                         mix_start = 1 - mix_start;
 190                         mix_end = 1 - mix_end;
 191                 }
 192
 193                 mix_audio( frame, b_frame, mix_start, mix_end, buffer, format, frequency, channels, samples );
 194         }
 195         else
 196         {
 197                 combine_audio( frame, b_frame, buffer, format, frequency, channels, samples );
 198         }
 199
 200         return 0;
 201 }
 202
 203
 204 /** Mix transition processing.
 205 */
 206
 207 static mlt_frame transition_process( mlt_transition this, mlt_frame a_frame, mlt_frame b_frame )
 208 {
 209         mlt_properties properties = MLT_TRANSITION_PROPERTIES( this );
 210         mlt_properties b_props = MLT_FRAME_PROPERTIES( b_frame );
 211
 212         // Only if mix is specified, otherwise a producer may set the mix
 213         if ( mlt_properties_get( properties, "start" ) != NULL )
 214         {
 215                 // Determine the time position of this frame in the transition duration
 216                 mlt_properties props = mlt_properties_get_data( MLT_FRAME_PROPERTIES( b_frame ), "_producer", NULL );
 217                 mlt_position in = mlt_properties_get_int( props, "in" );
 218                 mlt_position out = mlt_properties_get_int( props, "out" );
 219                 int length = mlt_properties_get_int(  MLT_TRANSITION_PROPERTIES( this ), "length" );
 220                 mlt_position time = mlt_properties_get_int( props, "_frame" );
 221                 double mix = mlt_transition_get_progress( this, b_frame );
 222                 if ( mlt_properties_get_int(  properties, "always_active" ) )
 223                         mix = ( double ) ( time - in ) / ( double ) ( out - in + 1 );
 224
 225                 // TODO: Check the logic here - shouldn't we be computing current and next mixing levels in all cases?
 226                 if ( length == 0 )
 227                 {
 228                         // If there is an end mix level adjust mix to the range
 229                         if ( mlt_properties_get( properties, "end" ) != NULL )
 230                         {
 231                                 double start = mlt_properties_get_double( properties, "start" );
 232                                 double end = mlt_properties_get_double( properties, "end" );
 233                                 mix = start + ( end - start ) * mix;
 234                         }
 235                         // A negative means total crossfade (uses position)
 236                         else if ( mlt_properties_get_double( properties, "start" ) >= 0 )
 237                         {
 238                                 // Otherwise, start/constructor is a constant mix level
 239                         mix = mlt_properties_get_double( properties, "start" );
 240                         }
 241
 242                         // Finally, set the mix property on the frame
 243                         mlt_properties_set_double( b_props, "audio.mix", mix );
 244
 245                         // Initialise transition previous mix value to prevent an inadvertant jump from 0
 246                         mlt_position last_position = mlt_properties_get_position( properties, "_last_position" );
 247                         mlt_position current_position = mlt_frame_get_position( b_frame );
 248                         mlt_properties_set_position( properties, "_last_position", current_position );
 249                         if ( mlt_properties_get( properties, "_previous_mix" ) == NULL
 250                              || current_position != last_position + 1 )
 251                                 mlt_properties_set_double( properties, "_previous_mix", mix );
 252
 253                         // Tell b frame what the previous mix level was
 254                         mlt_properties_set_double( b_props, "audio.previous_mix", mlt_properties_get_double( properties, "_previous_mix" ) );
 255
 256                         // Save the current mix level for the next iteration
 257                         mlt_properties_set_double( properties, "_previous_mix", mlt_properties_get_double( b_props, "audio.mix" ) );
 258
 259                         mlt_properties_set_double( b_props, "audio.reverse", mlt_properties_get_double( properties, "reverse" ) );
 260                 }
 261                 else
 262                 {
 263                         double level = mlt_properties_get_double( properties, "start" );
 264                         double mix_start = level;
 265                         double mix_end = mix_start;
 266                         double mix_increment = 1.0 / length;
 267                         if ( time - in < length )
 268                         {
 269                                 mix_start = mix_start * ( ( double )( time - in ) / length );
 270                                 mix_end = mix_start + mix_increment;
 271                         }
 272                         else if ( time > out - length )
 273                         {
 274                                 mix_end = mix_start * ( ( double )( out - time - in ) / length );
 275                                 mix_start = mix_end - mix_increment;
 276                         }
 277
 278                         mix_start = mix_start < 0 ? 0 : mix_start > level ? level : mix_start;
 279                         mix_end = mix_end < 0 ? 0 : mix_end > level ? level : mix_end;
 280                         mlt_properties_set_double( b_props, "audio.previous_mix", mix_start );
 281                         mlt_properties_set_double( b_props, "audio.mix", mix_end );
 282                 }
 283         }
 284
 285         // Override the get_audio method
 286         mlt_frame_push_audio( a_frame, this );
 287         mlt_frame_push_audio( a_frame, b_frame );
 288         mlt_frame_push_audio( a_frame, transition_get_audio );
 289
 290         return a_frame;
 291 }
 292
 293 /** Constructor for the transition.
 294 */
 295
 296 mlt_transition transition_mix_init( mlt_profile profile, mlt_service_type type, const char *id, char *arg )
 297 {
 298         mlt_transition this = calloc( 1, sizeof( struct mlt_transition_s ) );
 299         if ( this != NULL && mlt_transition_init( this, NULL ) == 0 )
 300         {
 301                 this->process = transition_process;
 302                 if ( arg != NULL )
 303                         mlt_properties_set_double( MLT_TRANSITION_PROPERTIES( this ), "start", atof( arg ) );
 304                 // Inform apps and framework that this is an audio only transition
 305                 mlt_properties_set_int( MLT_TRANSITION_PROPERTIES( this ), "_transition_type", 2 );
 306         }
 307         return this;
 308 }
 309