4d582328b6beb7ed2d6b6ce0cb88a1a2da91d26e
[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( test_properties, "rescale.interp", "nearest" );
223 mlt_properties_set_double( test_properties, "consumer_aspect_ratio", mlt_properties_get_double( properties, "consumer_aspect_ratio" ) );
224 mlt_frame_get_image( test_frame, buffer, format, width, height, writable );
225 mlt_properties_set_data( properties, "test_card_frame", test_frame, 0, ( mlt_destructor )mlt_frame_close, NULL );
226 mlt_properties_set_data( properties, "image", *buffer, *width * *height * 2, NULL, NULL );
227 mlt_properties_set_int( properties, "width", *width );
228 mlt_properties_set_int( properties, "height", *height );
229 mlt_properties_set( properties, "rescale.interp", "none" );
230 mlt_properties_set( properties, "scale", "off" );
231 }
232 else
233 {
234 mlt_properties_set_data( properties, "test_card_producer", NULL, 0, NULL, NULL );
235 mlt_frame_get_image( this, buffer, format, width, height, writable );
236 }
237 }
238 else
239 {
240 uint8_t *p;
241 uint8_t *q;
242 int size = 0;
243
244 *width = *width == 0 ? 720 : *width;
245 *height = *height == 0 ? 576 : *height;
246 size = *width * *height;
247
248 mlt_properties_set_int( properties, "width", *width );
249 mlt_properties_set_int( properties, "height", *height );
250 mlt_properties_set_int( properties, "aspect_ratio", 1 );
251
252 switch( *format )
253 {
254 case mlt_image_none:
255 size = 0;
256 *buffer = NULL;
257 break;
258 case mlt_image_rgb24:
259 size *= 3;
260 size += *width * 3;
261 *buffer = mlt_pool_alloc( size );
262 if ( *buffer )
263 memset( *buffer, 255, size );
264 break;
265 case mlt_image_rgb24a:
266 size *= 4;
267 size += *width * 4;
268 *buffer = mlt_pool_alloc( size );
269 if ( *buffer )
270 memset( *buffer, 255, size );
271 break;
272 case mlt_image_yuv422:
273 size *= 2;
274 size += *width * 2;
275 *buffer = mlt_pool_alloc( size );
276 p = *buffer;
277 q = p + size;
278 while ( p != NULL && p != q )
279 {
280 *p ++ = 235;
281 *p ++ = 128;
282 }
283 break;
284 case mlt_image_yuv420p:
285 size = size * 3 / 2;
286 *buffer = mlt_pool_alloc( size );
287 if ( *buffer )
288 memset( *buffer, 255, size );
289 break;
290 }
291
292 mlt_properties_set_data( properties, "image", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
293 mlt_properties_set_int( properties, "test_image", 1 );
294 }
295
296 return 0;
297 }
298
299 uint8_t *mlt_frame_get_alpha_mask( mlt_frame this )
300 {
301 if ( this->get_alpha_mask != NULL )
302 return this->get_alpha_mask( this );
303 return NULL;
304 }
305
306 int mlt_frame_get_audio( mlt_frame this, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
307 {
308 mlt_properties properties = mlt_frame_properties( this );
309
310 if ( this->get_audio != NULL )
311 {
312 return this->get_audio( this, buffer, format, frequency, channels, samples );
313 }
314 else
315 {
316 int size = 0;
317 *samples = *samples <= 0 ? 1920 : *samples;
318 *channels = *channels <= 0 ? 2 : *channels;
319 *frequency = *frequency <= 0 ? 48000 : *frequency;
320 size = *samples * *channels * sizeof( int16_t );
321 *buffer = mlt_pool_alloc( size );
322 if ( *buffer != NULL )
323 memset( *buffer, 0, size );
324 mlt_properties_set_data( properties, "audio", *buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
325 mlt_properties_set_int( properties, "test_audio", 1 );
326 }
327 return 0;
328 }
329
330 void mlt_frame_close( mlt_frame this )
331 {
332 if ( this != NULL )
333 {
334 mlt_deque_close( this->stack_image );
335 mlt_deque_close( this->stack_audio );
336 mlt_properties_close( &this->parent );
337 free( this );
338 }
339 }
340
341 /***** convenience functions *****/
342
343 int mlt_convert_rgb24a_to_yuv422( uint8_t *rgba, int width, int height, int stride, uint8_t *yuv, uint8_t *alpha )
344 {
345 int ret = 0;
346 register int y0, y1, u0, u1, v0, v1;
347 register int r, g, b;
348 register uint8_t *d = yuv;
349 register int i, j;
350
351 for ( i = 0; i < height; i++ )
352 {
353 register uint8_t *s = rgba + ( stride * i );
354 for ( j = 0; j < ( width / 2 ); j++ )
355 {
356 r = *s++;
357 g = *s++;
358 b = *s++;
359 *alpha++ = *s++;
360 RGB2YUV (r, g, b, y0, u0 , v0);
361 r = *s++;
362 g = *s++;
363 b = *s++;
364 *alpha++ = *s++;
365 RGB2YUV (r, g, b, y1, u1 , v1);
366 *d++ = y0;
367 *d++ = (u0+u1) >> 1;
368 *d++ = y1;
369 *d++ = (v0+v1) >> 1;
370 }
371 if ( width % 2 )
372 {
373 r = *s++;
374 g = *s++;
375 b = *s++;
376 *alpha++ = *s++;
377 RGB2YUV (r, g, b, y0, u0 , v0);
378 *d++ = y0;
379 *d++ = u0;
380 }
381 }
382 return ret;
383 }
384
385 int mlt_convert_rgb24_to_yuv422( uint8_t *rgb, int width, int height, int stride, uint8_t *yuv )
386 {
387 int ret = 0;
388 register int y0, y1, u0, u1, v0, v1;
389 register int r, g, b;
390 register uint8_t *d = yuv;
391 register int i, j;
392
393 for ( i = 0; i < height; i++ )
394 {
395 register uint8_t *s = rgb + ( stride * i );
396 for ( j = 0; j < ( width / 2 ); j++ )
397 {
398 r = *s++;
399 g = *s++;
400 b = *s++;
401 RGB2YUV (r, g, b, y0, u0 , v0);
402 r = *s++;
403 g = *s++;
404 b = *s++;
405 RGB2YUV (r, g, b, y1, u1 , v1);
406 *d++ = y0;
407 *d++ = (u0+u1) >> 1;
408 *d++ = y1;
409 *d++ = (v0+v1) >> 1;
410 }
411 if ( width % 2 )
412 {
413 r = *s++;
414 g = *s++;
415 b = *s++;
416 RGB2YUV (r, g, b, y0, u0 , v0);
417 *d++ = y0;
418 *d++ = u0;
419 }
420 }
421 return ret;
422 }
423
424 int mlt_convert_yuv420p_to_yuv422( uint8_t *yuv420p, int width, int height, int stride, uint8_t *yuv )
425 {
426 int ret = 0;
427 register int i, j;
428
429 int half = width >> 1;
430
431 uint8_t *Y = yuv420p;
432 uint8_t *U = Y + width * height;
433 uint8_t *V = U + width * height / 4;
434
435 register uint8_t *d = yuv;
436
437 for ( i = 0; i < height; i++ )
438 {
439 register uint8_t *u = U + ( i / 2 ) * ( half );
440 register uint8_t *v = V + ( i / 2 ) * ( half );
441
442 for ( j = 0; j < half; j++ )
443 {
444 *d ++ = *Y ++;
445 *d ++ = *u ++;
446 *d ++ = *Y ++;
447 *d ++ = *v ++;
448 }
449 }
450 return ret;
451 }
452
453 void mlt_resize_yuv422( uint8_t *output, int owidth, int oheight, uint8_t *input, int iwidth, int iheight )
454 {
455 // Calculate strides
456 int istride = iwidth * 2;
457 int ostride = owidth * 2;
458
459 iwidth = iwidth - ( iwidth % 4 );
460 owidth = owidth - ( owidth % 4 );
461 iheight = iheight - ( iheight % 2 );
462 oheight = oheight - ( oheight % 2 );
463
464 // Optimisation point
465 if ( iwidth == owidth && iheight == oheight )
466 memcpy( output, input, iheight * istride );
467
468 // Coordinates (0,0 is middle of output)
469 int y;
470
471 // Calculate ranges
472 int out_x_range = owidth / 2;
473 int out_y_range = oheight / 2;
474 int in_x_range = iwidth / 2 < out_x_range ? iwidth / 2 : out_x_range;
475 int in_y_range = iheight / 2 < out_y_range ? iheight / 2 : out_y_range;
476
477 // Output pointers
478 uint8_t *out_line = output;
479 uint8_t *out_ptr = out_line;
480
481 // Calculate a middle and possibly invalid pointer in the input
482 uint8_t *in_middle = input + istride * ( iheight / 2 ) + ( iwidth / 2 ) * 2;
483 int in_line = - in_y_range * istride - in_x_range * 2;
484
485 int elements;
486
487 // Fill whole section with black
488 y = out_y_range - ( iheight / 2 );
489 int blank_elements = ostride * y / 2;
490 elements = blank_elements;
491 while ( elements -- )
492 {
493 *out_line ++ = 16;
494 *out_line ++ = 128;
495 }
496
497 int active_width = 2 * iwidth;
498 int inactive_width = out_x_range - in_x_range;
499 uint8_t *p = NULL;
500 uint8_t *end = NULL;
501
502 // Loop for the entirety of our output height.
503 while ( iheight -- )
504 {
505 // Start at the beginning of the line
506 out_ptr = out_line;
507
508 // Fill the outer part with black
509 elements = inactive_width;
510 while ( elements -- )
511 {
512 *out_ptr ++ = 16;
513 *out_ptr ++ = 128;
514 }
515
516 // We're in the input range for this row.
517 p = in_middle + in_line;
518 end = out_ptr + active_width;
519 while ( out_ptr != end )
520 {
521 *out_ptr ++ = *p ++;
522 *out_ptr ++ = *p ++;
523 }
524
525 // Fill the outer part with black
526 elements = inactive_width;
527 while ( elements -- )
528 {
529 *out_ptr ++ = 16;
530 *out_ptr ++ = 128;
531 }
532
533 // Move to next input line
534 in_line += istride;
535
536 // Move to next output line
537 out_line += ostride;
538 }
539
540 // Fill whole section with black
541 elements = blank_elements;
542 while ( elements -- )
543 {
544 *out_line ++ = 16;
545 *out_line ++ = 128;
546 }
547 }
548
549 /** A resizing function for yuv422 frames - this does not rescale, but simply
550 resizes. It assumes yuv422 images available on the frame so use with care.
551 */
552
553 uint8_t *mlt_frame_resize_yuv422( mlt_frame this, int owidth, int oheight )
554 {
555 // Get properties
556 mlt_properties properties = mlt_frame_properties( this );
557
558 // Get the input image, width and height
559 uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
560 int iwidth = mlt_properties_get_int( properties, "width" );
561 int iheight = mlt_properties_get_int( properties, "height" );
562
563 // If width and height are correct, don't do anything
564 if ( iwidth != owidth || iheight != oheight )
565 {
566 // Create the output image
567 uint8_t *output = mlt_pool_alloc( owidth * ( oheight + 1 ) * 2 );
568
569 // Call the generic resize
570 mlt_resize_yuv422( output, owidth, oheight, input, iwidth, iheight );
571
572 // Now update the frame
573 mlt_properties_set_data( properties, "image", output, owidth * ( oheight + 1 ) * 2, ( mlt_destructor )mlt_pool_release, NULL );
574 mlt_properties_set_int( properties, "width", owidth );
575 mlt_properties_set_int( properties, "height", oheight );
576
577 // Return the output
578 return output;
579 }
580 // No change, return input
581 return input;
582 }
583
584 /** A rescaling function for yuv422 frames - low quality, and provided for testing
585 only. It assumes yuv422 images available on the frame so use with care.
586 */
587
588 uint8_t *mlt_frame_rescale_yuv422( mlt_frame this, int owidth, int oheight )
589 {
590 // Get properties
591 mlt_properties properties = mlt_frame_properties( this );
592
593 // Get the input image, width and height
594 uint8_t *input = mlt_properties_get_data( properties, "image", NULL );
595 int iwidth = mlt_properties_get_int( properties, "width" );
596 int iheight = mlt_properties_get_int( properties, "height" );
597
598 // If width and height are correct, don't do anything
599 if ( iwidth != owidth || iheight != oheight )
600 {
601 // Create the output image
602 uint8_t *output = mlt_pool_alloc( owidth * ( oheight + 1 ) * 2 );
603
604 // Calculate strides
605 int istride = iwidth * 2;
606 int ostride = owidth * 2;
607
608 iwidth = iwidth - ( iwidth % 4 );
609
610 // Derived coordinates
611 int dy, dx;
612
613 // Calculate ranges
614 int out_x_range = owidth / 2;
615 int out_y_range = oheight / 2;
616 int in_x_range = iwidth / 2;
617 int in_y_range = iheight / 2;
618
619 // Output pointers
620 register uint8_t *out_line = output;
621 register uint8_t *out_ptr;
622
623 // Calculate a middle pointer
624 uint8_t *in_middle = input + istride * in_y_range + in_x_range * 2;
625 uint8_t *in_line;
626
627 // Generate the affine transform scaling values
628 register int scale_width = ( iwidth << 16 ) / owidth;
629 register int scale_height = ( iheight << 16 ) / oheight;
630 register int base = 0;
631
632 int outer = out_x_range * scale_width;
633 int bottom = out_y_range * scale_height;
634
635 // Loop for the entirety of our output height.
636 for ( dy = - bottom; dy < bottom; dy += scale_height )
637 {
638 // Start at the beginning of the line
639 out_ptr = out_line;
640
641 // Pointer to the middle of the input line
642 in_line = in_middle + ( dy >> 16 ) * istride;
643
644 // Loop for the entirety of our output row.
645 for ( dx = - outer; dx < outer; dx += scale_width )
646 {
647 base = dx >> 15;
648 base &= 0xfffffffe;
649 *out_ptr ++ = *( in_line + base );
650 base &= 0xfffffffc;
651 *out_ptr ++ = *( in_line + base + 1 );
652 dx += scale_width;
653 base = dx >> 15;
654 base &= 0xfffffffe;
655 *out_ptr ++ = *( in_line + base );
656 base &= 0xfffffffc;
657 *out_ptr ++ = *( in_line + base + 3 );
658 }
659
660 // Move to next output line
661 out_line += ostride;
662 }
663
664 // Now update the frame
665 mlt_properties_set_data( properties, "image", output, owidth * ( oheight + 1 ) * 2, ( mlt_destructor )mlt_pool_release, NULL );
666 mlt_properties_set_int( properties, "width", owidth );
667 mlt_properties_set_int( properties, "height", oheight );
668
669 // Return the output
670 return output;
671 }
672
673 // No change, return input
674 return input;
675 }
676
677 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 )
678 {
679 int ret = 0;
680 int16_t *src, *dest;
681 int frequency_src = *frequency, frequency_dest = *frequency;
682 int channels_src = *channels, channels_dest = *channels;
683 int samples_src = *samples, samples_dest = *samples;
684 int i, j;
685 double d = 0, s = 0;
686
687 mlt_frame_get_audio( this, &dest, format, &frequency_dest, &channels_dest, &samples_dest );
688 //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" ) );
689 mlt_frame_get_audio( that, &src, format, &frequency_src, &channels_src, &samples_src );
690 //fprintf( stderr, "mix: frame src samples %d channels %d\n", samples_src, channels_src );
691
692 if ( channels_src > 6 )
693 channels_src = 0;
694 if ( channels_dest > 6 )
695 channels_dest = 0;
696 if ( samples_src > 4000 )
697 samples_src = 0;
698 if ( samples_dest > 4000 )
699 samples_dest = 0;
700
701 // determine number of samples to process
702 *samples = samples_src < samples_dest ? samples_src : samples_dest;
703 *channels = channels_src < channels_dest ? channels_src : channels_dest;
704 *buffer = dest;
705 *frequency = frequency_dest;
706
707 // Compute a smooth ramp over start to end
708 float weight = weight_start;
709 float weight_step = ( weight_end - weight_start ) / *samples;
710
711 // Mixdown
712 for ( i = 0; i < *samples; i++ )
713 {
714 for ( j = 0; j < *channels; j++ )
715 {
716 if ( j < channels_dest )
717 d = (double) dest[ i * channels_dest + j ];
718 if ( j < channels_src )
719 s = (double) src[ i * channels_src + j ];
720 dest[ i * channels_dest + j ] = s * weight + d * ( 1.0 - weight );
721 }
722 weight += weight_step;
723 }
724
725 return ret;
726 }
727
728 int mlt_sample_calculator( float fps, int frequency, int64_t position )
729 {
730 int samples = 0;
731
732 if ( fps > 29 && fps <= 30 )
733 {
734 samples = frequency / 30;
735
736 switch ( frequency )
737 {
738 case 48000:
739 if ( position % 5 != 0 )
740 samples += 2;
741 break;
742 case 44100:
743 if ( position % 300 == 0 )
744 samples = 1471;
745 else if ( position % 30 == 0 )
746 samples = 1470;
747 else if ( position % 2 == 0 )
748 samples = 1472;
749 else
750 samples = 1471;
751 break;
752 case 32000:
753 if ( position % 30 == 0 )
754 samples = 1068;
755 else if ( position % 29 == 0 )
756 samples = 1067;
757 else if ( position % 4 == 2 )
758 samples = 1067;
759 else
760 samples = 1068;
761 break;
762 default:
763 samples = 0;
764 }
765 }
766 else if ( fps != 0 )
767 {
768 samples = frequency / fps;
769 }
770
771 return samples;
772 }