2 * mlt_frame.c -- interface for all frame classes
3 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
4 * Author: Charles Yates <charles.yates@pandora.be>
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.
22 #include "mlt_frame.h"
23 #include "mlt_producer.h"
24 #include "mlt_factory.h"
29 /** Constructor for a frame.
32 mlt_frame mlt_frame_init( )
35 mlt_frame this = calloc( sizeof( struct mlt_frame_s ), 1 );
39 // Get the normalisation
40 char *normalisation = mlt_environment( "MLT_NORMALISATION" );
42 // Initialise the properties
43 mlt_properties properties = &this->parent;
44 mlt_properties_init( properties, this );
46 // Set default properties on the frame
47 mlt_properties_set_position( properties, "_position", 0.0 );
48 mlt_properties_set_data( properties, "image", NULL, 0, NULL, NULL );
50 if ( normalisation == NULL || strcmp( normalisation, "NTSC" ) )
52 mlt_properties_set_int( properties, "width", 720 );
53 mlt_properties_set_int( properties, "height", 576 );
54 mlt_properties_set_int( properties, "normalised_width", 720 );
55 mlt_properties_set_int( properties, "normalised_height", 576 );
56 mlt_properties_set_double( properties, "aspect_ratio", 59.0/54.0 );
60 mlt_properties_set_int( properties, "width", 720 );
61 mlt_properties_set_int( properties, "height", 480 );
62 mlt_properties_set_int( properties, "normalised_width", 720 );
63 mlt_properties_set_int( properties, "normalised_height", 480 );
64 mlt_properties_set_double( properties, "aspect_ratio", 10.0/11.0 );
67 mlt_properties_set_data( properties, "audio", NULL, 0, NULL, NULL );
68 mlt_properties_set_data( properties, "alpha", NULL, 0, NULL, NULL );
70 // Construct stacks for frames and methods
71 this->stack_image = mlt_deque_init( );
72 this->stack_audio = mlt_deque_init( );
73 this->stack_service = mlt_deque_init( );
79 /** Fetch the frames properties.
82 mlt_properties mlt_frame_properties( mlt_frame this )
84 return this != NULL ? &this->parent : NULL;
87 /** Check if we have a way to derive something other than a test card.
90 int mlt_frame_is_test_card( mlt_frame this )
92 return mlt_deque_count( this->stack_image ) == 0 || mlt_properties_get_int( MLT_FRAME_PROPERTIES( this ), "test_image" );
95 /** Check if we have a way to derive something other than test audio.
98 int mlt_frame_is_test_audio( mlt_frame this )
100 return mlt_deque_count( this->stack_audio ) == 0 || mlt_properties_get_int( MLT_FRAME_PROPERTIES( this ), "test_audio" );
103 /** Get the aspect ratio of the frame.
106 double mlt_frame_get_aspect_ratio( mlt_frame this )
108 return mlt_properties_get_double( MLT_FRAME_PROPERTIES( this ), "aspect_ratio" );
111 /** Set the aspect ratio of the frame.
114 int mlt_frame_set_aspect_ratio( mlt_frame this, double value )
116 return mlt_properties_set_double( MLT_FRAME_PROPERTIES( this ), "aspect_ratio", value );
119 /** Get the position of this frame.
122 mlt_position mlt_frame_get_position( mlt_frame this )
124 int pos = mlt_properties_get_position( MLT_FRAME_PROPERTIES( this ), "_position" );
125 return pos < 0 ? 0 : pos;
128 /** Set the position of this frame.
131 int mlt_frame_set_position( mlt_frame this, mlt_position value )
133 return mlt_properties_set_position( MLT_FRAME_PROPERTIES( this ), "_position", value );
136 /** Stack a get_image callback.
139 int mlt_frame_push_get_image( mlt_frame this, mlt_get_image get_image )
141 return mlt_deque_push_back( this->stack_image, get_image );
144 /** Pop a get_image callback.
147 mlt_get_image mlt_frame_pop_get_image( mlt_frame this )
149 return mlt_deque_pop_back( this->stack_image );
155 int mlt_frame_push_frame( mlt_frame this, mlt_frame that )
157 return mlt_deque_push_back( this->stack_image, that );
163 mlt_frame mlt_frame_pop_frame( mlt_frame this )
165 return mlt_deque_pop_back( this->stack_image );
171 int mlt_frame_push_service( mlt_frame this, void *that )
173 return mlt_deque_push_back( this->stack_image, that );
179 void *mlt_frame_pop_service( mlt_frame this )
181 return mlt_deque_pop_back( this->stack_image );
187 int mlt_frame_push_service_int( mlt_frame this, int that )
189 return mlt_deque_push_back_int( this->stack_image, that );
195 int mlt_frame_pop_service_int( mlt_frame this )
197 return mlt_deque_pop_back_int( this->stack_image );
200 /** Push an audio item on the stack.
203 int mlt_frame_push_audio( mlt_frame this, void *that )
205 return mlt_deque_push_back( this->stack_audio, that );
208 /** Pop an audio item from the stack
211 void *mlt_frame_pop_audio( mlt_frame this )
213 return mlt_deque_pop_back( this->stack_audio );
216 /** Return the service stack
219 mlt_deque mlt_frame_service_stack( mlt_frame this )
221 return this->stack_service;
224 /** Replace image stack with the information provided.
226 This might prove to be unreliable and restrictive - the idea is that a transition
227 which normally uses two images may decide to only use the b frame (ie: in the case
228 of a composite where the b frame completely obscures the a frame).
230 The image must be writable and the destructor for the image itself must be taken
231 care of on another frame and that frame cannot have a replace applied to it...
232 Further it assumes that no alpha mask is in use.
234 For these reasons, it can only be used in a specific situation - when you have
235 multiple tracks each with their own transition and these transitions are applied
236 in a strictly reversed order (ie: highest numbered [lowest track] is processed
239 More reliable approach - the cases should be detected during the process phase
240 and the upper tracks should simply not be invited to stack...
243 void mlt_frame_replace_image( mlt_frame this, uint8_t *image, mlt_image_format format, int width, int height )
245 // Remove all items from the stack
246 while( mlt_deque_pop_back( this->stack_image ) ) ;
248 // Update the information
249 mlt_properties_set_data( MLT_FRAME_PROPERTIES( this ), "image", image, 0, NULL, NULL );
250 mlt_properties_set_int( MLT_FRAME_PROPERTIES( this ), "width", width );
251 mlt_properties_set_int( MLT_FRAME_PROPERTIES( this ), "height", height );
252 mlt_properties_set_int( MLT_FRAME_PROPERTIES( this ), "format", format );
253 this->get_alpha_mask = NULL;
256 /** Get the image associated to the frame.
259 int mlt_frame_get_image( mlt_frame this, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
261 mlt_properties properties = MLT_FRAME_PROPERTIES( this );
262 mlt_get_image get_image = mlt_frame_pop_get_image( this );
263 mlt_producer producer = mlt_properties_get_data( properties, "test_card_producer", NULL );
266 if ( get_image != NULL )
268 mlt_properties_set_int( properties, "image_count", mlt_properties_get_int( properties, "image_count" ) - 1 );
269 mlt_position position = mlt_frame_get_position( this );
270 error = get_image( this, buffer, format, width, height, writable );
271 mlt_properties_set_int( properties, "width", *width );
272 mlt_properties_set_int( properties, "height", *height );
273 mlt_properties_set_int( properties, "format", *format );
274 mlt_frame_set_position( this, position );
276 else if ( mlt_properties_get_data( properties, "image", NULL ) != NULL )
278 *format = mlt_properties_get_int( properties, "format" );
279 *buffer = mlt_properties_get_data( properties, "image", NULL );
280 *width = mlt_properties_get_int( properties, "width" );
281 *height = mlt_properties_get_int( properties, "height" );
283 else if ( producer != NULL )
285 mlt_frame test_frame = NULL;
286 mlt_service_get_frame( MLT_PRODUCER_SERVICE( producer ), &test_frame, 0 );
287 if ( test_frame != NULL )
289 mlt_properties test_properties = MLT_FRAME_PROPERTIES( test_frame );
290 mlt_properties_set_double( test_properties, "consumer_aspect_ratio", mlt_properties_get_double( properties, "consumer_aspect_ratio" ) );
291 mlt_properties_set( test_properties, "rescale.interp", mlt_properties_get( properties, "rescale.interp" ) );
292 mlt_frame_get_image( test_frame, buffer, format, width, height, writable );
293 mlt_properties_set_data( properties, "test_card_frame", test_frame, 0, ( mlt_destructor )mlt_frame_close, NULL );
294 mlt_properties_set_data( properties, "image", *buffer, *width * *height * 2, NULL, NULL );
295 mlt_properties_set_int( properties, "width", *width );
296 mlt_properties_set_int( properties, "height", *height );
297 mlt_properties_set_int( properties, "format", *format );
298 mlt_properties_set_double( properties, "aspect_ratio", mlt_frame_get_aspect_ratio( test_frame ) );
302 mlt_properties_set_data( properties, "test_card_producer", NULL, 0, NULL, NULL );
303 mlt_frame_get_image( this, buffer, format, width, height, writable );
312 *width = *width == 0 ? 720 : *width;
313 *height = *height == 0 ? 576 : *height;
314 size = *width * *height;
316 mlt_properties_set_int( properties, "format", *format );
317 mlt_properties_set_int( properties, "width", *width );
318 mlt_properties_set_int( properties, "height", *height );
319 mlt_properties_set_int( properties, "aspect_ratio", 0 );
327 case mlt_image_rgb24:
330 *buffer = mlt_pool_alloc( size );
332 memset( *buffer, 255, size );
334 case mlt_image_rgb24a:
335 case mlt_image_opengl:
338 *buffer = mlt_pool_alloc( size );
340 memset( *buffer, 255, size );
342 case mlt_image_yuv422:
345 *buffer = mlt_pool_alloc( size );
348 while ( p != NULL && p != q )
354 case mlt_image_yuv420p:
356 *buffer = mlt_pool_alloc( size );
358 memset( *buffer, 255, size );
362 mlt_properties_set_data( properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
363 mlt_properties_set_int( properties, "test_image", 1 );
366 mlt_properties_set_int( properties, "scaled_width", *width );
367 mlt_properties_set_int( properties, "scaled_height", *height );
372 uint8_t *mlt_frame_get_alpha_mask( mlt_frame this )
374 uint8_t *alpha = NULL;
377 if ( this->get_alpha_mask != NULL )
378 alpha = this->get_alpha_mask( this );
380 alpha = mlt_properties_get_data( &this->parent, "alpha", NULL );
383 int size = mlt_properties_get_int( &this->parent, "scaled_width" ) * mlt_properties_get_int( &this->parent, "scaled_height" );
384 alpha = mlt_pool_alloc( size );
385 memset( alpha, 255, size );
386 mlt_properties_set_data( &this->parent, "alpha", alpha, size, mlt_pool_release, NULL );
392 int mlt_frame_get_audio( mlt_frame this, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
394 mlt_get_audio get_audio = mlt_frame_pop_audio( this );
395 mlt_properties properties = MLT_FRAME_PROPERTIES( this );
396 int hide = mlt_properties_get_int( properties, "test_audio" );
398 if ( hide == 0 && get_audio != NULL )
400 mlt_position position = mlt_frame_get_position( this );
401 get_audio( this, buffer, format, frequency, channels, samples );
402 mlt_frame_set_position( this, position );
404 else if ( mlt_properties_get_data( properties, "audio", NULL ) )
406 *buffer = mlt_properties_get_data( properties, "audio", NULL );
407 *frequency = mlt_properties_get_int( properties, "audio_frequency" );
408 *channels = mlt_properties_get_int( properties, "audio_channels" );
409 *samples = mlt_properties_get_int( properties, "audio_samples" );
414 *samples = *samples <= 0 ? 1920 : *samples;
415 *channels = *channels <= 0 ? 2 : *channels;
416 *frequency = *frequency <= 0 ? 48000 : *frequency;
417 size = *samples * *channels * sizeof( int16_t );
418 *buffer = mlt_pool_alloc( size );
419 if ( *buffer != NULL )
420 memset( *buffer, 0, size );
421 mlt_properties_set_data( properties, "audio", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
422 mlt_properties_set_int( properties, "test_audio", 1 );
425 mlt_properties_set_int( properties, "audio_frequency", *frequency );
426 mlt_properties_set_int( properties, "audio_channels", *channels );
427 mlt_properties_set_int( properties, "audio_samples", *samples );
429 if ( mlt_properties_get( properties, "meta.volume" ) )
431 double value = mlt_properties_get_double( properties, "meta.volume" );
435 memset( *buffer, 0, *samples * *channels * 2 );
437 else if ( value != 1.0 )
439 int total = *samples * *channels;
440 int16_t *p = *buffer;
448 mlt_properties_set( properties, "meta.volume", NULL );
454 unsigned char *mlt_frame_get_waveform( mlt_frame this, int w, int h )
457 mlt_properties properties = MLT_FRAME_PROPERTIES( this );
458 mlt_audio_format format = mlt_audio_pcm;
459 int frequency = 32000; // lower frequency available?
461 double fps = mlt_properties_get_double( properties, "fps" );
462 int samples = mlt_sample_calculator( fps, frequency, mlt_frame_get_position( this ) );
465 mlt_frame_get_audio( this, &pcm, &format, &frequency, &channels, &samples );
467 // Make an 8-bit buffer large enough to hold rendering
469 unsigned char *bitmap = ( unsigned char* )mlt_pool_alloc( size );
470 if ( bitmap != NULL )
471 memset( bitmap, 0, size );
472 mlt_properties_set_data( properties, "waveform", bitmap, size, ( mlt_destructor )mlt_pool_release, NULL );
474 // Render vertical lines
475 int16_t *ubound = pcm + samples * channels;
476 int skip = samples / w - 1;
479 // Iterate sample stream and along x coordinate
480 for ( i = 0; i < w && pcm < ubound; i++ )
482 // pcm data has channels interleaved
483 for ( j = 0; j < channels; j++ )
485 // Determine sample's magnitude from 2s complement;
486 int pcm_magnitude = *pcm < 0 ? ~(*pcm) + 1 : *pcm;
487 // The height of a line is the ratio of the magnitude multiplied by
488 // half the vertical resolution
489 int height = ( int )( ( double )( pcm_magnitude ) / 32768 * h / 2 );
490 // Determine the starting y coordinate - left channel above center,
491 // right channel below - currently assumes 2 channels
492 int displacement = ( h / 2 ) - ( 1 - j ) * height;
493 // Position buffer pointer using y coordinate, stride, and x coordinate
494 unsigned char *p = &bitmap[ i + displacement * w ];
496 // Draw vertical line
497 for ( k = 0; k < height; k++ )
502 pcm += skip * channels;
508 mlt_producer mlt_frame_get_original_producer( mlt_frame this )
511 return mlt_properties_get_data( MLT_FRAME_PROPERTIES( this ), "_producer", NULL );
515 void mlt_frame_close( mlt_frame this )
517 if ( this != NULL && mlt_properties_dec_ref( MLT_FRAME_PROPERTIES( this ) ) <= 0 )
519 mlt_deque_close( this->stack_image );
520 mlt_deque_close( this->stack_audio );
521 while( mlt_deque_peek_back( this->stack_service ) )
522 mlt_service_close( mlt_deque_pop_back( this->stack_service ) );
523 mlt_deque_close( this->stack_service );
524 mlt_properties_close( &this->parent );
529 /***** convenience functions *****/
531 int mlt_convert_rgb24a_to_yuv422( uint8_t *rgba, int width, int height, int stride, uint8_t *yuv, uint8_t *alpha )
534 register int y0, y1, u0, u1, v0, v1;
535 register int r, g, b;
536 register uint8_t *d = yuv;
539 for ( i = 0; i < height; i++ )
541 register uint8_t *s = rgba + ( stride * i );
542 for ( j = 0; j < ( width / 2 ); j++ )
548 RGB2YUV (r, g, b, y0, u0 , v0);
553 RGB2YUV (r, g, b, y1, u1 , v1);
565 RGB2YUV (r, g, b, y0, u0 , v0);
573 int mlt_convert_rgb24_to_yuv422( uint8_t *rgb, int width, int height, int stride, uint8_t *yuv )
576 register int y0, y1, u0, u1, v0, v1;
577 register int r, g, b;
578 register uint8_t *d = yuv;
581 for ( i = 0; i < height; i++ )
583 register uint8_t *s = rgb + ( stride * i );
584 for ( j = 0; j < ( width / 2 ); j++ )
589 RGB2YUV (r, g, b, y0, u0 , v0);
593 RGB2YUV (r, g, b, y1, u1 , v1);
604 RGB2YUV (r, g, b, y0, u0 , v0);
612 int mlt_convert_yuv420p_to_yuv422( uint8_t *yuv420p, int width, int height, int stride, uint8_t *yuv )
617 int half = width >> 1;
619 uint8_t *Y = yuv420p;
620 uint8_t *U = Y + width * height;
621 uint8_t *V = U + width * height / 4;
623 register uint8_t *d = yuv;
625 for ( i = 0; i < height; i++ )
627 register uint8_t *u = U + ( i / 2 ) * ( half );
628 register uint8_t *v = V + ( i / 2 ) * ( half );
630 for ( j = 0; j < half; j++ )
641 uint8_t *mlt_resize_alpha( uint8_t *input, int owidth, int oheight, int iwidth, int iheight )
643 uint8_t *output = NULL;
645 if ( input != NULL && ( iwidth != owidth || iheight != oheight ) && ( owidth > 6 && oheight > 6 ) )
648 int offset_x = ( owidth - iwidth ) / 2;
649 int offset_y = ( oheight - iheight ) / 2;
652 output = mlt_pool_alloc( owidth * oheight );
653 memset( output, 0, owidth * oheight );
655 offset_x -= offset_x % 2;
657 out_line = output + offset_y * owidth;
658 out_line += offset_x;
660 // Loop for the entirety of our output height.
663 // We're in the input range for this row.
664 memcpy( out_line, input, iused );
666 // Move to next input line
669 // Move to next output line
677 void mlt_resize_yuv422( uint8_t *output, int owidth, int oheight, uint8_t *input, int iwidth, int iheight )
680 int istride = iwidth * 2;
681 int ostride = owidth * 2;
682 int offset_x = ( owidth - iwidth );
683 int offset_y = ( oheight - iheight ) / 2;
684 uint8_t *in_line = input;
686 int size = owidth * oheight;
689 // Optimisation point
690 if ( output == NULL || input == NULL || ( owidth <= 6 || oheight <= 6 || iwidth <= 6 || oheight <= 6 ) )
694 else if ( iwidth == owidth && iheight == oheight )
696 memcpy( output, input, iheight * istride );
706 offset_x -= offset_x % 4;
708 out_line = output + offset_y * ostride;
709 out_line += offset_x;
711 // Loop for the entirety of our output height.
714 // We're in the input range for this row.
715 memcpy( out_line, in_line, iwidth * 2 );
717 // Move to next input line
720 // Move to next output line
725 /** A resizing function for yuv422 frames - this does not rescale, but simply
726 resizes. It assumes yuv422 images available on the frame so use with care.
729 uint8_t *mlt_frame_resize_yuv422( mlt_frame this, int owidth, int oheight )
732 mlt_properties properties = MLT_FRAME_PROPERTIES( this );
734 // Get the input image, width and height
735 uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
736 uint8_t *alpha = mlt_frame_get_alpha_mask( this );
738 int iwidth = mlt_properties_get_int( properties, "width" );
739 int iheight = mlt_properties_get_int( properties, "height" );
741 // If width and height are correct, don't do anything
742 if ( iwidth != owidth || iheight != oheight )
744 // Create the output image
745 uint8_t *output = mlt_pool_alloc( owidth * ( oheight + 1 ) * 2 );
747 // Call the generic resize
748 mlt_resize_yuv422( output, owidth, oheight, input, iwidth, iheight );
750 // Now update the frame
751 mlt_properties_set_data( properties, "image", output, owidth * ( oheight + 1 ) * 2, ( mlt_destructor )mlt_pool_release, NULL );
752 mlt_properties_set_int( properties, "width", owidth );
753 mlt_properties_set_int( properties, "height", oheight );
755 // We should resize the alpha too
756 alpha = mlt_resize_alpha( alpha, owidth, oheight, iwidth, iheight );
759 mlt_properties_set_data( properties, "alpha", alpha, owidth * oheight, ( mlt_destructor )mlt_pool_release, NULL );
760 this->get_alpha_mask = NULL;
766 // No change, return input
770 /** A rescaling function for yuv422 frames - low quality, and provided for testing
771 only. It assumes yuv422 images available on the frame so use with care.
774 uint8_t *mlt_frame_rescale_yuv422( mlt_frame this, int owidth, int oheight )
777 mlt_properties properties = MLT_FRAME_PROPERTIES( this );
779 // Get the input image, width and height
780 uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
781 int iwidth = mlt_properties_get_int( properties, "width" );
782 int iheight = mlt_properties_get_int( properties, "height" );
784 // If width and height are correct, don't do anything
785 if ( iwidth != owidth || iheight != oheight )
787 // Create the output image
788 uint8_t *output = mlt_pool_alloc( owidth * ( oheight + 1 ) * 2 );
791 int istride = iwidth * 2;
792 int ostride = owidth * 2;
794 iwidth = iwidth - ( iwidth % 4 );
796 // Derived coordinates
800 int out_x_range = owidth / 2;
801 int out_y_range = oheight / 2;
802 int in_x_range = iwidth / 2;
803 int in_y_range = iheight / 2;
806 register uint8_t *out_line = output;
807 register uint8_t *out_ptr;
809 // Calculate a middle pointer
810 uint8_t *in_middle = input + istride * in_y_range + in_x_range * 2;
813 // Generate the affine transform scaling values
814 register int scale_width = ( iwidth << 16 ) / owidth;
815 register int scale_height = ( iheight << 16 ) / oheight;
816 register int base = 0;
818 int outer = out_x_range * scale_width;
819 int bottom = out_y_range * scale_height;
821 // Loop for the entirety of our output height.
822 for ( dy = - bottom; dy < bottom; dy += scale_height )
824 // Start at the beginning of the line
827 // Pointer to the middle of the input line
828 in_line = in_middle + ( dy >> 16 ) * istride;
830 // Loop for the entirety of our output row.
831 for ( dx = - outer; dx < outer; dx += scale_width )
835 *out_ptr ++ = *( in_line + base );
837 *out_ptr ++ = *( in_line + base + 1 );
841 *out_ptr ++ = *( in_line + base );
843 *out_ptr ++ = *( in_line + base + 3 );
846 // Move to next output line
850 // Now update the frame
851 mlt_properties_set_data( properties, "image", output, owidth * ( oheight + 1 ) * 2, ( mlt_destructor )mlt_pool_release, NULL );
852 mlt_properties_set_int( properties, "width", owidth );
853 mlt_properties_set_int( properties, "height", oheight );
859 // No change, return input
863 int mlt_frame_mix_audio( mlt_frame this, mlt_frame that, float weight_start, float weight_end, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
867 int frequency_src = *frequency, frequency_dest = *frequency;
868 int channels_src = *channels, channels_dest = *channels;
869 int samples_src = *samples, samples_dest = *samples;
873 mlt_frame_get_audio( that, &src, format, &frequency_src, &channels_src, &samples_src );
874 mlt_frame_get_audio( this, &dest, format, &frequency_dest, &channels_dest, &samples_dest );
876 int silent = mlt_properties_get_int( MLT_FRAME_PROPERTIES( this ), "silent_audio" );
877 mlt_properties_set_int( MLT_FRAME_PROPERTIES( this ), "silent_audio", 0 );
879 memset( dest, 0, samples_dest * channels_dest * sizeof( int16_t ) );
881 silent = mlt_properties_get_int( MLT_FRAME_PROPERTIES( that ), "silent_audio" );
882 mlt_properties_set_int( MLT_FRAME_PROPERTIES( that ), "silent_audio", 0 );
884 memset( src, 0, samples_src * channels_src * sizeof( int16_t ) );
886 if ( channels_src > 6 )
888 if ( channels_dest > 6 )
890 if ( samples_src > 4000 )
892 if ( samples_dest > 4000 )
895 // determine number of samples to process
896 *samples = samples_src < samples_dest ? samples_src : samples_dest;
897 *channels = channels_src < channels_dest ? channels_src : channels_dest;
899 *frequency = frequency_dest;
901 // Compute a smooth ramp over start to end
902 float weight = weight_start;
903 float weight_step = ( weight_end - weight_start ) / *samples;
906 for ( i = 0; i < *samples; i++ )
908 for ( j = 0; j < *channels; j++ )
910 if ( j < channels_dest )
911 d = (double) dest[ i * channels_dest + j ];
912 if ( j < channels_src )
913 s = (double) src[ i * channels_src + j ];
914 dest[ i * channels_dest + j ] = s * weight + d * ( 1.0 - weight );
916 weight += weight_step;
922 /* Will this break when mlt_position is converted to double? -Zach */
923 int mlt_sample_calculator( float fps, int frequency, int64_t position )
927 if ( ( int )( fps * 100 ) == 2997 )
929 samples = frequency / 30;
934 if ( position % 5 != 0 )
938 if ( position % 300 == 0 )
940 else if ( position % 30 == 0 )
942 else if ( position % 2 == 0 )
948 if ( position % 30 == 0 )
950 else if ( position % 29 == 0 )
952 else if ( position % 4 == 2 )
963 samples = frequency / fps;
969 int64_t mlt_sample_calculator_to_now( float fps, int frequency, int64_t frame )
973 // TODO: Correct rules for NTSC and drop the * 100 hack
974 if ( ( int )( fps * 100 ) == 2997 )
976 samples = ( ( double )( frame * frequency ) / 30 );
980 samples += 2 * ( frame / 5 );
983 samples += frame + ( frame / 2 ) - ( frame / 30 ) + ( frame / 300 );
986 samples += ( 2 * frame ) - ( frame / 4 ) - ( frame / 29 );
992 samples = ( ( frame * frequency ) / ( int )fps );