timespecsub(&time_end, &time_start, &elapsed);
dbg("Elapsed s: %ld ns: %ld", elapsed.tv_sec, elapsed.tv_nsec);
if (elapsed.tv_sec == 0 && elapsed.tv_nsec < NSEC_PER_SEC / FPS) {
timespecsub(&time_end, &time_start, &elapsed);
dbg("Elapsed s: %ld ns: %ld", elapsed.tv_sec, elapsed.tv_nsec);
if (elapsed.tv_sec == 0 && elapsed.tv_nsec < NSEC_PER_SEC / FPS) {