ffmpeg/libav/tick.h

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/* tick.h - Compute successive integer multiples of a rational
* number without long-term rounding error.
* (c)2002 by Lennert Buytenhek <buytenh@gnu.org>
* File licensed under the GPL, see http://www.fsf.org/ for more info.
* Dedicated to Marija Kulikova.
*/
#include "avcodec.h"
typedef struct Ticker {
int value;
int inrate;
int outrate;
int div;
int mod;
} Ticker;
extern void ticker_init(Ticker *tick, INT64 inrate, INT64 outrate);
static inline int ticker_tick(Ticker *tick, int num)
{
int n = num * tick->div;
tick->value += num * tick->mod;
#if 1
if (tick->value > 0) {
n += (tick->value / tick->inrate);
tick->value = tick->value % tick->inrate;
if (tick->value > 0) {
tick->value -= tick->inrate;
n++;
}
}
#else
while (tick->value > 0) {
tick->value -= tick->inrate;
n++;
}
#endif
return n;
}
static inline INT64 ticker_abs(Ticker *tick, int num)
{
INT64 n = (INT64) num * tick->div;
INT64 value = (INT64) num * tick->mod;
if (value > 0) {
n += (value / tick->inrate);
value = value % tick->inrate;
if (value > 0) {
/* value -= tick->inrate; */
n++;
}
}
return n;
}