Audio read ahead and fine tuning
[melted] / src / framework / mlt_frame.c
1 /*
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>
5 *
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.
10 *
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.
15 *
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.
19 */
20
21 #include "config.h"
22 #include "mlt_frame.h"
23 #include "mlt_producer.h"
24 #include "mlt_factory.h"
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28
29 /** Constructor for a frame.
30 */
31
32 mlt_frame mlt_frame_init( )
33 {
34 // Allocate a frame
35 mlt_frame this = calloc( sizeof( struct mlt_frame_s ), 1 );
36
37 if ( this != NULL )
38 {
39 // Get the normalisation
40 char *normalisation = mlt_environment( "MLT_NORMALISATION" );
41
42 // Initialise the properties
43 mlt_properties properties = &this->parent;
44 mlt_properties_init( properties, this );
45
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 );
49
50 if ( normalisation == NULL || strcmp( normalisation, "NTSC" ) )
51 {
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", 72.0/79.0 );
57 }
58 else
59 {
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", 128.0/117.0 );
65 }
66
67 mlt_properties_set_data( properties, "audio", NULL, 0, NULL, NULL );
68 mlt_properties_set_data( properties, "alpha", NULL, 0, NULL, NULL );
69
70 // Construct stacks for frames and methods
71 this->stack_image = mlt_deque_init( );
72 this->stack_audio = mlt_deque_init( );
73 }
74
75 return this;
76 }
77
78 /** Fetch the frames properties.
79 */
80
81 mlt_properties mlt_frame_properties( mlt_frame this )
82 {
83 return &this->parent;
84 }
85
86 /** Check if we have a way to derive something other than a test card.
87 */
88
89 int mlt_frame_is_test_card( mlt_frame this )
90 {
91 return mlt_deque_count( this->stack_image ) == 0 || mlt_properties_get_int( mlt_frame_properties( this ), "test_image" );
92 }
93
94 /** Check if we have a way to derive something than test audio.
95 */
96
97 int mlt_frame_is_test_audio( mlt_frame this )
98 {
99 return this->get_audio == NULL || mlt_properties_get_int( mlt_frame_properties( this ), "test_audio" );
100 }
101
102 /** Get the aspect ratio of the frame.
103 */
104
105 double mlt_frame_get_aspect_ratio( mlt_frame this )
106 {
107 return mlt_properties_get_double( mlt_frame_properties( this ), "aspect_ratio" );
108 }
109
110 /** Set the aspect ratio of the frame.
111 */
112
113 int mlt_frame_set_aspect_ratio( mlt_frame this, double value )
114 {
115 return mlt_properties_set_double( mlt_frame_properties( this ), "aspect_ratio", value );
116 }
117
118 /** Get the position of this frame.
119 */
120
121 mlt_position mlt_frame_get_position( mlt_frame this )
122 {
123 return mlt_properties_get_position( mlt_frame_properties( this ), "_position" );
124 }
125
126 /** Set the position of this frame.
127 */
128
129 int mlt_frame_set_position( mlt_frame this, mlt_position value )
130 {
131 return mlt_properties_set_position( mlt_frame_properties( this ), "_position", value );
132 }
133
134 /** Stack a get_image callback.
135 */
136
137 int mlt_frame_push_get_image( mlt_frame this, mlt_get_image get_image )
138 {
139 return mlt_deque_push_back( this->stack_image, get_image );
140 }
141
142 /** Pop a get_image callback.
143 */
144
145 mlt_get_image mlt_frame_pop_get_image( mlt_frame this )
146 {
147 return mlt_deque_pop_back( this->stack_image );
148 }
149
150 /** Push a frame.
151 */
152
153 int mlt_frame_push_frame( mlt_frame this, mlt_frame that )
154 {
155 return mlt_deque_push_back( this->stack_image, that );
156 }
157
158 /** Pop a frame.
159 */
160
161 mlt_frame mlt_frame_pop_frame( mlt_frame this )
162 {
163 return mlt_deque_pop_back( this->stack_image );
164 }
165
166 /** Push a service.
167 */
168
169 int mlt_frame_push_service( mlt_frame this, void *that )
170 {
171 return mlt_deque_push_back( this->stack_image, that );
172 }
173
174 /** Pop a service.
175 */
176
177 void *mlt_frame_pop_service( mlt_frame this )
178 {
179 return mlt_deque_pop_back( this->stack_image );
180 }
181
182 /** Push an audio item on the stack.
183 */
184
185 int mlt_frame_push_audio( mlt_frame this, void *that )
186 {
187 return mlt_deque_push_back( this->stack_audio, that );
188 }
189
190 /** Pop an audio item from the stack
191 */
192
193 void *mlt_frame_pop_audio( mlt_frame this )
194 {
195 return mlt_deque_pop_back( this->stack_audio );
196 }
197
198 int mlt_frame_get_image( mlt_frame this, uint8_t **buffer, mlt_image_format *format, int *width, int *height, int writable )
199 {
200 mlt_properties properties = mlt_frame_properties( this );
201 mlt_get_image get_image = mlt_frame_pop_get_image( this );
202 mlt_producer producer = mlt_properties_get_data( properties, "test_card_producer", NULL );
203
204 if ( get_image != NULL )
205 {
206 return get_image( this, buffer, format, width, height, writable );
207 }
208 else if ( mlt_properties_get_data( properties, "image", NULL ) != NULL )
209 {
210 *format = mlt_image_yuv422;
211 *buffer = mlt_properties_get_data( properties, "image", NULL );
212 *width = mlt_properties_get_int( properties, "width" );
213 *height = mlt_properties_get_int( properties, "height" );
214 }
215 else if ( producer != NULL )
216 {
217 mlt_frame test_frame = NULL;
218 mlt_service_get_frame( mlt_producer_service( producer ), &test_frame, 0 );
219 if ( test_frame != NULL )
220 {
221 mlt_properties test_properties = mlt_frame_properties( test_frame );
222 mlt_properties_set_double( test_properties, "consumer_aspect_ratio", mlt_properties_get_double( properties, "consumer_aspect_ratio" ) );
223 mlt_frame_get_image( test_frame, buffer, format, width, height, writable );
224 mlt_properties_set_data( properties, "test_card_frame", test_frame, 0, ( mlt_destructor )mlt_frame_close, NULL );
225 mlt_properties_set_data( properties, "image", *buffer, *width * *height * 2, NULL, NULL );
226 mlt_properties_set_int( properties, "width", *width );
227 mlt_properties_set_int( properties, "height", *height );
228 mlt_properties_set( properties, "rescale.interp", "none" );
229 mlt_properties_set( properties, "scale", "off" );
230 }
231 else
232 {
233 mlt_properties_set_data( properties, "test_card_producer", NULL, 0, NULL, NULL );
234 mlt_frame_get_image( this, buffer, format, width, height, writable );
235 }
236 }
237 else
238 {
239 register uint8_t *p;
240 register uint8_t *q;
241 int size = 0;
242
243 *width = *width == 0 ? 720 : *width;
244 *height = *height == 0 ? 576 : *height;
245 size = *width * *height;
246
247 mlt_properties_set_int( properties, "width", *width );
248 mlt_properties_set_int( properties, "height", *height );
249 mlt_properties_set_int( properties, "aspect_ratio", 1 );
250
251 switch( *format )
252 {
253 case mlt_image_none:
254 size = 0;
255 *buffer = NULL;
256 break;
257 case mlt_image_rgb24:
258 size *= 3;
259 size += *width * 3;
260 *buffer = mlt_pool_alloc( size );
261 if ( *buffer )
262 memset( *buffer, 255, size );
263 break;
264 case mlt_image_rgb24a:
265 size *= 4;
266 size += *width * 4;
267 *buffer = mlt_pool_alloc( size );
268 if ( *buffer )
269 memset( *buffer, 255, size );
270 break;
271 case mlt_image_yuv422:
272 size *= 2;
273 size += *width * 2;
274 *buffer = mlt_pool_alloc( size );
275 p = *buffer;
276 q = p + size;
277 while ( p != NULL && p != q )
278 {
279 *p ++ = 235;
280 *p ++ = 128;
281 }
282 break;
283 case mlt_image_yuv420p:
284 size = size * 3 / 2;
285 *buffer = mlt_pool_alloc( size );
286 if ( *buffer )
287 memset( *buffer, 255, size );
288 break;
289 }
290
291 mlt_properties_set_data( properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
292 mlt_properties_set_int( properties, "test_image", 1 );
293 }
294
295 return 0;
296 }
297
298 uint8_t *mlt_frame_get_alpha_mask( mlt_frame this )
299 {
300 if ( this->get_alpha_mask != NULL )
301 return this->get_alpha_mask( this );
302 return NULL;
303 }
304
305 int mlt_frame_get_audio( mlt_frame this, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
306 {
307 mlt_properties properties = mlt_frame_properties( this );
308
309 if ( this->get_audio != NULL )
310 {
311 this->get_audio( this, buffer, format, frequency, channels, samples );
312 }
313 else if ( mlt_properties_get_data( properties, "audio", NULL ) )
314 {
315 *buffer = mlt_properties_get_data( properties, "audio", NULL );
316 *frequency = mlt_properties_get_int( properties, "audio_frequency" );
317 *channels = mlt_properties_get_int( properties, "audio_channels" );
318 *samples = mlt_properties_get_int( properties, "audio_samples" );
319 }
320 else
321 {
322 int size = 0;
323 *samples = *samples <= 0 ? 1920 : *samples;
324 *channels = *channels <= 0 ? 2 : *channels;
325 *frequency = *frequency <= 0 ? 48000 : *frequency;
326 size = *samples * *channels * sizeof( int16_t );
327 *buffer = mlt_pool_alloc( size );
328 if ( *buffer != NULL )
329 memset( *buffer, 0, size );
330 mlt_properties_set_data( properties, "audio", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
331 mlt_properties_set_int( properties, "test_audio", 1 );
332 }
333
334 mlt_properties_set_int( properties, "audio_frequency", *frequency );
335 mlt_properties_set_int( properties, "audio_channels", *channels );
336 mlt_properties_set_int( properties, "audio_samples", *samples );
337
338 return 0;
339 }
340
341 void mlt_frame_close( mlt_frame this )
342 {
343 if ( this != NULL )
344 {
345 mlt_deque_close( this->stack_image );
346 mlt_deque_close( this->stack_audio );
347 mlt_properties_close( &this->parent );
348 free( this );
349 }
350 }
351
352 /***** convenience functions *****/
353
354 int mlt_convert_rgb24a_to_yuv422( uint8_t *rgba, int width, int height, int stride, uint8_t *yuv, uint8_t *alpha )
355 {
356 int ret = 0;
357 register int y0, y1, u0, u1, v0, v1;
358 register int r, g, b;
359 register uint8_t *d = yuv;
360 register int i, j;
361
362 for ( i = 0; i < height; i++ )
363 {
364 register uint8_t *s = rgba + ( stride * i );
365 for ( j = 0; j < ( width / 2 ); j++ )
366 {
367 r = *s++;
368 g = *s++;
369 b = *s++;
370 *alpha++ = *s++;
371 RGB2YUV (r, g, b, y0, u0 , v0);
372 r = *s++;
373 g = *s++;
374 b = *s++;
375 *alpha++ = *s++;
376 RGB2YUV (r, g, b, y1, u1 , v1);
377 *d++ = y0;
378 *d++ = (u0+u1) >> 1;
379 *d++ = y1;
380 *d++ = (v0+v1) >> 1;
381 }
382 if ( width % 2 )
383 {
384 r = *s++;
385 g = *s++;
386 b = *s++;
387 *alpha++ = *s++;
388 RGB2YUV (r, g, b, y0, u0 , v0);
389 *d++ = y0;
390 *d++ = u0;
391 }
392 }
393 return ret;
394 }
395
396 int mlt_convert_rgb24_to_yuv422( uint8_t *rgb, int width, int height, int stride, uint8_t *yuv )
397 {
398 int ret = 0;
399 register int y0, y1, u0, u1, v0, v1;
400 register int r, g, b;
401 register uint8_t *d = yuv;
402 register int i, j;
403
404 for ( i = 0; i < height; i++ )
405 {
406 register uint8_t *s = rgb + ( stride * i );
407 for ( j = 0; j < ( width / 2 ); j++ )
408 {
409 r = *s++;
410 g = *s++;
411 b = *s++;
412 RGB2YUV (r, g, b, y0, u0 , v0);
413 r = *s++;
414 g = *s++;
415 b = *s++;
416 RGB2YUV (r, g, b, y1, u1 , v1);
417 *d++ = y0;
418 *d++ = (u0+u1) >> 1;
419 *d++ = y1;
420 *d++ = (v0+v1) >> 1;
421 }
422 if ( width % 2 )
423 {
424 r = *s++;
425 g = *s++;
426 b = *s++;
427 RGB2YUV (r, g, b, y0, u0 , v0);
428 *d++ = y0;
429 *d++ = u0;
430 }
431 }
432 return ret;
433 }
434
435 int mlt_convert_yuv420p_to_yuv422( uint8_t *yuv420p, int width, int height, int stride, uint8_t *yuv )
436 {
437 int ret = 0;
438 register int i, j;
439
440 int half = width >> 1;
441
442 uint8_t *Y = yuv420p;
443 uint8_t *U = Y + width * height;
444 uint8_t *V = U + width * height / 4;
445
446 register uint8_t *d = yuv;
447
448 for ( i = 0; i < height; i++ )
449 {
450 register uint8_t *u = U + ( i / 2 ) * ( half );
451 register uint8_t *v = V + ( i / 2 ) * ( half );
452
453 for ( j = 0; j < half; j++ )
454 {
455 *d ++ = *Y ++;
456 *d ++ = *u ++;
457 *d ++ = *Y ++;
458 *d ++ = *v ++;
459 }
460 }
461 return ret;
462 }
463
464 void mlt_resize_yuv422( uint8_t *output, int owidth, int oheight, uint8_t *input, int iwidth, int iheight )
465 {
466 // Calculate strides
467 int istride = iwidth * 2;
468 int ostride = owidth * 2;
469
470 iwidth = iwidth - ( iwidth % 4 );
471 owidth = owidth - ( owidth % 4 );
472 iheight = iheight - ( iheight % 2 );
473 oheight = oheight - ( oheight % 2 );
474
475 // Optimisation point
476 if ( iwidth == owidth && iheight == oheight )
477 memcpy( output, input, iheight * istride );
478
479 // Coordinates (0,0 is middle of output)
480 int y;
481
482 // Calculate ranges
483 int out_x_range = owidth / 2;
484 int out_y_range = oheight / 2;
485 int in_x_range = iwidth / 2 < out_x_range ? iwidth / 2 : out_x_range;
486 int in_y_range = iheight / 2 < out_y_range ? iheight / 2 : out_y_range;
487
488 // Output pointers
489 uint8_t *out_line = output;
490 uint8_t *out_ptr = out_line;
491
492 // Calculate a middle and possibly invalid pointer in the input
493 uint8_t *in_middle = input + istride * ( iheight / 2 ) + ( iwidth / 2 ) * 2;
494 int in_line = - in_y_range * istride - in_x_range * 2;
495
496 int elements;
497
498 // Fill whole section with black
499 y = out_y_range - ( iheight / 2 );
500 int blank_elements = ostride * y / 2;
501 elements = blank_elements;
502 while ( elements -- )
503 {
504 *out_line ++ = 16;
505 *out_line ++ = 128;
506 }
507
508 int active_width = 2 * iwidth;
509 int inactive_width = out_x_range - in_x_range;
510 uint8_t *p = NULL;
511 uint8_t *end = NULL;
512
513 // Loop for the entirety of our output height.
514 while ( iheight -- )
515 {
516 // Start at the beginning of the line
517 out_ptr = out_line;
518
519 // Fill the outer part with black
520 elements = inactive_width;
521 while ( elements -- )
522 {
523 *out_ptr ++ = 16;
524 *out_ptr ++ = 128;
525 }
526
527 // We're in the input range for this row.
528 p = in_middle + in_line;
529 end = out_ptr + active_width;
530 while ( out_ptr != end )
531 {
532 *out_ptr ++ = *p ++;
533 *out_ptr ++ = *p ++;
534 }
535
536 // Fill the outer part with black
537 elements = inactive_width;
538 while ( elements -- )
539 {
540 *out_ptr ++ = 16;
541 *out_ptr ++ = 128;
542 }
543
544 // Move to next input line
545 in_line += istride;
546
547 // Move to next output line
548 out_line += ostride;
549 }
550
551 // Fill whole section with black
552 elements = blank_elements;
553 while ( elements -- )
554 {
555 *out_line ++ = 16;
556 *out_line ++ = 128;
557 }
558 }
559
560 /** A resizing function for yuv422 frames - this does not rescale, but simply
561 resizes. It assumes yuv422 images available on the frame so use with care.
562 */
563
564 uint8_t *mlt_frame_resize_yuv422( mlt_frame this, int owidth, int oheight )
565 {
566 // Get properties
567 mlt_properties properties = mlt_frame_properties( this );
568
569 // Get the input image, width and height
570 uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
571 int iwidth = mlt_properties_get_int( properties, "width" );
572 int iheight = mlt_properties_get_int( properties, "height" );
573
574 // If width and height are correct, don't do anything
575 if ( iwidth != owidth || iheight != oheight )
576 {
577 // Create the output image
578 uint8_t *output = mlt_pool_alloc( owidth * ( oheight + 1 ) * 2 );
579
580 // Call the generic resize
581 mlt_resize_yuv422( output, owidth, oheight, input, iwidth, iheight );
582
583 // Now update the frame
584 mlt_properties_set_data( properties, "image", output, owidth * ( oheight + 1 ) * 2, ( mlt_destructor )mlt_pool_release, NULL );
585 mlt_properties_set_int( properties, "width", owidth );
586 mlt_properties_set_int( properties, "height", oheight );
587
588 // Return the output
589 return output;
590 }
591 // No change, return input
592 return input;
593 }
594
595 /** A rescaling function for yuv422 frames - low quality, and provided for testing
596 only. It assumes yuv422 images available on the frame so use with care.
597 */
598
599 uint8_t *mlt_frame_rescale_yuv422( mlt_frame this, int owidth, int oheight )
600 {
601 // Get properties
602 mlt_properties properties = mlt_frame_properties( this );
603
604 // Get the input image, width and height
605 uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
606 int iwidth = mlt_properties_get_int( properties, "width" );
607 int iheight = mlt_properties_get_int( properties, "height" );
608
609 // If width and height are correct, don't do anything
610 if ( iwidth != owidth || iheight != oheight )
611 {
612 // Create the output image
613 uint8_t *output = mlt_pool_alloc( owidth * ( oheight + 1 ) * 2 );
614
615 // Calculate strides
616 int istride = iwidth * 2;
617 int ostride = owidth * 2;
618
619 iwidth = iwidth - ( iwidth % 4 );
620
621 // Derived coordinates
622 int dy, dx;
623
624 // Calculate ranges
625 int out_x_range = owidth / 2;
626 int out_y_range = oheight / 2;
627 int in_x_range = iwidth / 2;
628 int in_y_range = iheight / 2;
629
630 // Output pointers
631 register uint8_t *out_line = output;
632 register uint8_t *out_ptr;
633
634 // Calculate a middle pointer
635 uint8_t *in_middle = input + istride * in_y_range + in_x_range * 2;
636 uint8_t *in_line;
637
638 // Generate the affine transform scaling values
639 register int scale_width = ( iwidth << 16 ) / owidth;
640 register int scale_height = ( iheight << 16 ) / oheight;
641 register int base = 0;
642
643 int outer = out_x_range * scale_width;
644 int bottom = out_y_range * scale_height;
645
646 // Loop for the entirety of our output height.
647 for ( dy = - bottom; dy < bottom; dy += scale_height )
648 {
649 // Start at the beginning of the line
650 out_ptr = out_line;
651
652 // Pointer to the middle of the input line
653 in_line = in_middle + ( dy >> 16 ) * istride;
654
655 // Loop for the entirety of our output row.
656 for ( dx = - outer; dx < outer; dx += scale_width )
657 {
658 base = dx >> 15;
659 base &= 0xfffffffe;
660 *out_ptr ++ = *( in_line + base );
661 base &= 0xfffffffc;
662 *out_ptr ++ = *( in_line + base + 1 );
663 dx += scale_width;
664 base = dx >> 15;
665 base &= 0xfffffffe;
666 *out_ptr ++ = *( in_line + base );
667 base &= 0xfffffffc;
668 *out_ptr ++ = *( in_line + base + 3 );
669 }
670
671 // Move to next output line
672 out_line += ostride;
673 }
674
675 // Now update the frame
676 mlt_properties_set_data( properties, "image", output, owidth * ( oheight + 1 ) * 2, ( mlt_destructor )mlt_pool_release, NULL );
677 mlt_properties_set_int( properties, "width", owidth );
678 mlt_properties_set_int( properties, "height", oheight );
679
680 // Return the output
681 return output;
682 }
683
684 // No change, return input
685 return input;
686 }
687
688 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 )
689 {
690 int ret = 0;
691 int16_t *src, *dest;
692 int frequency_src = *frequency, frequency_dest = *frequency;
693 int channels_src = *channels, channels_dest = *channels;
694 int samples_src = *samples, samples_dest = *samples;
695 int i, j;
696 double d = 0, s = 0;
697
698 mlt_frame_get_audio( this, &dest, format, &frequency_dest, &channels_dest, &samples_dest );
699 //fprintf( stderr, "mix: frame dest samples %d channels %d position %lld\n", samples_dest, channels_dest, mlt_properties_get_position( mlt_frame_properties( this ), "_position" ) );
700 mlt_frame_get_audio( that, &src, format, &frequency_src, &channels_src, &samples_src );
701 //fprintf( stderr, "mix: frame src samples %d channels %d\n", samples_src, channels_src );
702
703 if ( channels_src > 6 )
704 channels_src = 0;
705 if ( channels_dest > 6 )
706 channels_dest = 0;
707 if ( samples_src > 4000 )
708 samples_src = 0;
709 if ( samples_dest > 4000 )
710 samples_dest = 0;
711
712 // determine number of samples to process
713 *samples = samples_src < samples_dest ? samples_src : samples_dest;
714 *channels = channels_src < channels_dest ? channels_src : channels_dest;
715 *buffer = dest;
716 *frequency = frequency_dest;
717
718 // Compute a smooth ramp over start to end
719 float weight = weight_start;
720 float weight_step = ( weight_end - weight_start ) / *samples;
721
722 // Mixdown
723 for ( i = 0; i < *samples; i++ )
724 {
725 for ( j = 0; j < *channels; j++ )
726 {
727 if ( j < channels_dest )
728 d = (double) dest[ i * channels_dest + j ];
729 if ( j < channels_src )
730 s = (double) src[ i * channels_src + j ];
731 dest[ i * channels_dest + j ] = s * weight + d * ( 1.0 - weight );
732 }
733 weight += weight_step;
734 }
735
736 return ret;
737 }
738
739 int mlt_sample_calculator( float fps, int frequency, int64_t position )
740 {
741 int samples = 0;
742
743 if ( ( int )( fps * 100 ) == 2997 )
744 {
745 samples = frequency / 30;
746
747 switch ( frequency )
748 {
749 case 48000:
750 if ( position % 5 != 0 )
751 samples += 2;
752 break;
753 case 44100:
754 if ( position % 300 == 0 )
755 samples = 1471;
756 else if ( position % 30 == 0 )
757 samples = 1470;
758 else if ( position % 2 == 0 )
759 samples = 1472;
760 else
761 samples = 1471;
762 break;
763 case 32000:
764 if ( position % 30 == 0 )
765 samples = 1068;
766 else if ( position % 29 == 0 )
767 samples = 1067;
768 else if ( position % 4 == 2 )
769 samples = 1067;
770 else
771 samples = 1068;
772 break;
773 default:
774 samples = 0;
775 }
776 }
777 else if ( fps != 0 )
778 {
779 samples = frequency / fps;
780 }
781
782 return samples;
783 }