2 * libmad - MPEG audio decoder library
3 * Copyright (C) 2000-2004 Underbit Technologies, Inc.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 * $Id: timer.c,v 1.18 2004/01/23 09:41:33 rob Exp $
36 mad_timer_t const mad_timer_zero = { 0, 0 };
39 * NAME: timer->compare()
40 * DESCRIPTION: indicate relative order of two timers
42 int mad_timer_compare(mad_timer_t timer1, mad_timer_t timer2)
46 diff = timer1.seconds - timer2.seconds;
52 diff = timer1.fraction - timer2.fraction;
62 * NAME: timer->negate()
63 * DESCRIPTION: invert the sign of a timer
65 void mad_timer_negate(mad_timer_t *timer)
67 timer->seconds = -timer->seconds;
69 if (timer->fraction) {
71 timer->fraction = MAD_TIMER_RESOLUTION - timer->fraction;
77 * DESCRIPTION: return the absolute value of a timer
79 mad_timer_t mad_timer_abs(mad_timer_t timer)
81 if (timer.seconds < 0)
82 mad_timer_negate(&timer);
88 * NAME: reduce_timer()
89 * DESCRIPTION: carry timer fraction into seconds
92 void reduce_timer(mad_timer_t *timer)
94 timer->seconds += timer->fraction / MAD_TIMER_RESOLUTION;
95 timer->fraction %= MAD_TIMER_RESOLUTION;
100 * DESCRIPTION: compute greatest common denominator
103 unsigned long gcd(unsigned long num1, unsigned long num2)
117 * NAME: reduce_rational()
118 * DESCRIPTION: convert rational expression to lowest terms
121 void reduce_rational(unsigned long *numer, unsigned long *denom)
123 unsigned long factor;
125 factor = gcd(*numer, *denom);
134 * NAME: scale_rational()
135 * DESCRIPTION: solve numer/denom == ?/scale avoiding overflowing
138 unsigned long scale_rational(unsigned long numer, unsigned long denom,
141 reduce_rational(&numer, &denom);
142 reduce_rational(&scale, &denom);
147 return numer * (scale / denom) + numer * (scale % denom) / denom;
149 return scale * (numer / denom) + scale * (numer % denom) / denom;
151 return numer * scale / denom;
156 * DESCRIPTION: set timer to specific (positive) value
158 void mad_timer_set(mad_timer_t *timer, unsigned long seconds,
159 unsigned long numer, unsigned long denom)
161 timer->seconds = seconds;
162 if (numer >= denom && denom > 0) {
163 timer->seconds += numer / denom;
173 case MAD_TIMER_RESOLUTION:
174 timer->fraction = numer;
178 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 1000);
182 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 8000);
186 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 11025);
190 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 12000);
194 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 16000);
198 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 22050);
202 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 24000);
206 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 32000);
210 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 44100);
214 timer->fraction = numer * (MAD_TIMER_RESOLUTION / 48000);
218 timer->fraction = scale_rational(numer, denom, MAD_TIMER_RESOLUTION);
222 if (timer->fraction >= MAD_TIMER_RESOLUTION)
228 * DESCRIPTION: add one timer to another
230 void mad_timer_add(mad_timer_t *timer, mad_timer_t incr)
232 timer->seconds += incr.seconds;
233 timer->fraction += incr.fraction;
235 if (timer->fraction >= MAD_TIMER_RESOLUTION)
240 * NAME: timer->multiply()
241 * DESCRIPTION: multiply a timer by a scalar value
243 void mad_timer_multiply(mad_timer_t *timer, signed long scalar)
246 unsigned long factor;
251 mad_timer_negate(timer);
255 *timer = mad_timer_zero;
259 mad_timer_add(timer, addend);
261 mad_timer_add(&addend, addend);
267 * NAME: timer->count()
268 * DESCRIPTION: return timer value in selected units
270 signed long mad_timer_count(mad_timer_t timer, enum mad_units units)
273 case MAD_UNITS_HOURS:
274 return timer.seconds / 60 / 60;
276 case MAD_UNITS_MINUTES:
277 return timer.seconds / 60;
279 case MAD_UNITS_SECONDS:
280 return timer.seconds;
282 case MAD_UNITS_DECISECONDS:
283 case MAD_UNITS_CENTISECONDS:
284 case MAD_UNITS_MILLISECONDS:
286 case MAD_UNITS_8000_HZ:
287 case MAD_UNITS_11025_HZ:
288 case MAD_UNITS_12000_HZ:
289 case MAD_UNITS_16000_HZ:
290 case MAD_UNITS_22050_HZ:
291 case MAD_UNITS_24000_HZ:
292 case MAD_UNITS_32000_HZ:
293 case MAD_UNITS_44100_HZ:
294 case MAD_UNITS_48000_HZ:
296 case MAD_UNITS_24_FPS:
297 case MAD_UNITS_25_FPS:
298 case MAD_UNITS_30_FPS:
299 case MAD_UNITS_48_FPS:
300 case MAD_UNITS_50_FPS:
301 case MAD_UNITS_60_FPS:
302 case MAD_UNITS_75_FPS:
303 return timer.seconds * (signed long) units +
304 (signed long) scale_rational(timer.fraction, MAD_TIMER_RESOLUTION,
307 case MAD_UNITS_23_976_FPS:
308 case MAD_UNITS_24_975_FPS:
309 case MAD_UNITS_29_97_FPS:
310 case MAD_UNITS_47_952_FPS:
311 case MAD_UNITS_49_95_FPS:
312 case MAD_UNITS_59_94_FPS:
313 return (mad_timer_count(timer, -units) + 1) * 1000 / 1001;
316 /* unsupported units */
321 * NAME: timer->fraction()
322 * DESCRIPTION: return fractional part of timer in arbitrary terms
324 unsigned long mad_timer_fraction(mad_timer_t timer, unsigned long denom)
326 timer = mad_timer_abs(timer);
330 return timer.fraction ?
331 MAD_TIMER_RESOLUTION / timer.fraction : MAD_TIMER_RESOLUTION + 1;
333 case MAD_TIMER_RESOLUTION:
334 return timer.fraction;
337 return scale_rational(timer.fraction, MAD_TIMER_RESOLUTION, denom);
342 * NAME: timer->string()
343 * DESCRIPTION: write a string representation of a timer using a template
345 void mad_timer_string(mad_timer_t timer,
346 char *dest, char const *format, enum mad_units units,
347 enum mad_units fracunits, unsigned long subparts)
349 unsigned long hours, minutes, seconds, sub;
352 timer = mad_timer_abs(timer);
354 seconds = timer.seconds;
358 case MAD_UNITS_HOURS:
359 case MAD_UNITS_MINUTES:
360 case MAD_UNITS_SECONDS:
363 case MAD_UNITS_DECISECONDS:
364 case MAD_UNITS_CENTISECONDS:
365 case MAD_UNITS_MILLISECONDS:
367 case MAD_UNITS_8000_HZ:
368 case MAD_UNITS_11025_HZ:
369 case MAD_UNITS_12000_HZ:
370 case MAD_UNITS_16000_HZ:
371 case MAD_UNITS_22050_HZ:
372 case MAD_UNITS_24000_HZ:
373 case MAD_UNITS_32000_HZ:
374 case MAD_UNITS_44100_HZ:
375 case MAD_UNITS_48000_HZ:
377 case MAD_UNITS_24_FPS:
378 case MAD_UNITS_25_FPS:
379 case MAD_UNITS_30_FPS:
380 case MAD_UNITS_48_FPS:
381 case MAD_UNITS_50_FPS:
382 case MAD_UNITS_60_FPS:
383 case MAD_UNITS_75_FPS:
387 denom = MAD_TIMER_RESOLUTION / fracunits;
389 frac = timer.fraction / denom;
390 sub = scale_rational(timer.fraction % denom, denom, subparts);
394 case MAD_UNITS_23_976_FPS:
395 case MAD_UNITS_24_975_FPS:
396 case MAD_UNITS_29_97_FPS:
397 case MAD_UNITS_47_952_FPS:
398 case MAD_UNITS_49_95_FPS:
399 case MAD_UNITS_59_94_FPS:
400 /* drop-frame encoding */
401 /* N.B. this is only well-defined for MAD_UNITS_29_97_FPS */
403 unsigned long frame, cycle, d, m;
405 frame = mad_timer_count(timer, fracunits);
407 cycle = -fracunits * 60 * 10 - (10 - 1) * 2;
411 frame += (10 - 1) * 2 * d;
413 frame += 2 * ((m - 2) / (cycle / 10));
415 frac = frame % -fracunits;
416 seconds = frame / -fracunits;
422 case MAD_UNITS_HOURS:
423 minutes = seconds / 60;
424 hours = minutes / 60;
426 sprintf(dest, format,
428 (unsigned int) (minutes % 60),
429 (unsigned int) (seconds % 60),
433 case MAD_UNITS_MINUTES:
434 minutes = seconds / 60;
436 sprintf(dest, format,
438 (unsigned int) (seconds % 60),
442 case MAD_UNITS_SECONDS:
443 sprintf(dest, format,
448 case MAD_UNITS_23_976_FPS:
449 case MAD_UNITS_24_975_FPS:
450 case MAD_UNITS_29_97_FPS:
451 case MAD_UNITS_47_952_FPS:
452 case MAD_UNITS_49_95_FPS:
453 case MAD_UNITS_59_94_FPS:
455 /* not yet implemented */
461 case MAD_UNITS_DECISECONDS:
462 case MAD_UNITS_CENTISECONDS:
463 case MAD_UNITS_MILLISECONDS:
465 case MAD_UNITS_8000_HZ:
466 case MAD_UNITS_11025_HZ:
467 case MAD_UNITS_12000_HZ:
468 case MAD_UNITS_16000_HZ:
469 case MAD_UNITS_22050_HZ:
470 case MAD_UNITS_24000_HZ:
471 case MAD_UNITS_32000_HZ:
472 case MAD_UNITS_44100_HZ:
473 case MAD_UNITS_48000_HZ:
475 case MAD_UNITS_24_FPS:
476 case MAD_UNITS_25_FPS:
477 case MAD_UNITS_30_FPS:
478 case MAD_UNITS_48_FPS:
479 case MAD_UNITS_50_FPS:
480 case MAD_UNITS_60_FPS:
481 case MAD_UNITS_75_FPS:
482 sprintf(dest, format, mad_timer_count(timer, units), sub);