fix a number of errors with BBT time computations, mostly notably ones related to tempo-only change
git-svn-id: svn://localhost/ardour2/branches/3.0@11020 d708f5d6-7413-0410-9779-e7cbd77b26cf
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@ -54,15 +54,15 @@ Tempo::frames_per_beat (framecnt_t sr) const
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/***********************************************************************/
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double
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Meter::frames_per_bar (const Tempo& tempo, framecnt_t sr) const
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Meter::frames_per_division (const Tempo& tempo, framecnt_t sr) const
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{
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return (60.0 * sr * _divisions_per_bar) / tempo.beats_per_minute();
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return (60.0 * sr) / (tempo.beats_per_minute() * (_note_type/tempo.note_type()));
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}
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double
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Meter::frames_per_division (const Tempo& tempo, framecnt_t sr) const
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Meter::frames_per_bar (const Tempo& tempo, framecnt_t sr) const
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{
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return (60.0 * sr) / (tempo.beats_per_minute() * _note_type/tempo.note_type());
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return frames_per_division (tempo, sr) * _divisions_per_bar;
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}
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/***********************************************************************/
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@ -862,52 +862,54 @@ TempoMap::bbt_time_unlocked (framepos_t frame, BBT_Time& bbt) const
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void
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TempoMap::bbt_time_with_metric (framepos_t frame, BBT_Time& bbt, const TempoMetric& metric) const
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{
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framecnt_t frame_diff;
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const double divisions_per_bar = metric.meter().divisions_per_bar();
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const double ticks_per_frame = metric.meter().frames_per_division (metric.tempo(),_frame_rate) / BBT_Time::ticks_per_beat;
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const double frames_per_tick = metric.meter().frames_per_division (metric.tempo(),_frame_rate) / BBT_Time::ticks_per_beat;
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// cerr << "*** Compute BBT time for " << frame
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// << " from metric at " << metric.frame() << " tempo = " << metric.tempo().beats_per_minute () << " meter "
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// << metric.meter().divisions_per_bar() << '/' << metric.meter().note_divisor()
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// << endl;
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/* now compute how far beyond the metric we actually are, and add the
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* relevant number of ticks to the metric's BBT time
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*/
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/* now compute how far beyond that point we actually are. */
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framecnt_t frame_diff = frame - metric.frame();
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uint32_t tick_diff = (uint32_t) lrint ((double) frame_diff / frames_per_tick);
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frame_diff = frame - metric.frame();
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bbt.ticks = metric.start().ticks + tick_diff;
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uint32_t beat_overflow = bbt.ticks / (uint32_t) BBT_Time::ticks_per_beat;
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bbt.ticks = bbt.ticks % (uint32_t) BBT_Time::ticks_per_beat;
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bbt.beats = metric.start().beats + beat_overflow;
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/* bbt.beats uses 1-based counting, so adjust to get the right answer */
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uint32_t bar_overflow = (bbt.beats - 1) / (uint32_t) divisions_per_bar;
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bbt.bars = metric.start().bars + bar_overflow;
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bbt.ticks = metric.start().ticks + (uint32_t)round((double)frame_diff / ticks_per_frame);
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uint32_t xtra_beats = bbt.ticks / (uint32_t)BBT_Time::ticks_per_beat;
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bbt.ticks %= (uint32_t)BBT_Time::ticks_per_beat;
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/* fmod will map bbt.beats as follows:
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bbt.beats = metric.start().beats + xtra_beats - 1; // correction for 1-based counting, see below for matching operation.
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bbt.bars = metric.start().bars + (uint32_t)floor((double)bbt.beats / divisions_per_bar);
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bbt.beats = (uint32_t)fmod((double)bbt.beats, divisions_per_bar);
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Beats divisions per bar Normalized beat
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0 N => 0
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1 N => 1
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2 N => 2
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3 N => 3
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.
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.
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.
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N-1 N => N-1
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N N => 0
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N+1 N => 1
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.
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.
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.
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2N-1 N => N-1
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2N N => 0
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/* if we have a fractional number of beats per bar, we see if
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we're in the last beat (the fractional one). if so, we
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round ticks appropriately and bump to the next bar.
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so, the only special cases are 0, N, 2N etc. however bbt.beats is
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never zero, so the only actual special cases are N, 2N and so on,
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allowing us to use a special case check for fmod () == 0 and
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changing the value to divisions per bar
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*/
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double beat_fraction = divisions_per_bar - floor(divisions_per_bar);
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/* XXX one problem here is that I'm not sure how to handle
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fractional beats that don't evenly divide ticks_per_beat.
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If they aren't handled consistently, I would guess we'll
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continue to have strange discrepancies occuring. Perhaps
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this will also behave badly in the case of meters like
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0.1/4, but I can't be bothered to test that.
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*/
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uint32_t ticks_on_last_beat = (uint32_t)floor(BBT_Time::ticks_per_beat * beat_fraction);
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bbt.beats = (uint32_t) fmod (bbt.beats, divisions_per_bar);
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if (bbt.beats > (uint32_t)floor(divisions_per_bar) && bbt.ticks >= ticks_on_last_beat) {
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bbt.ticks -= ticks_on_last_beat;
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bbt.beats = 0;
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bbt.bars++;
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if (bbt.beats == 0) {
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bbt.beats = divisions_per_bar;
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}
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bbt.beats++; // correction for 1-based counting, see above for matching operation.
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// cerr << "-----\t RETURN " << bbt << endl;
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}
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framecnt_t
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@ -1417,6 +1419,8 @@ TempoMap::get_points (framepos_t lower, framepos_t upper) const
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frames_per_bar = meter->frames_per_bar (*tempo, _frame_rate);
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beat_frames = meter->frames_per_division (*tempo,_frame_rate);
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// cerr << "Start with beat frames = " << beat_frames << " bar = " << frames_per_bar << endl;
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if (meter->frame() > tempo->frame()) {
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bar = meter->start().bars;
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beat = meter->start().beats;
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@ -1448,7 +1452,7 @@ TempoMap::get_points (framepos_t lower, framepos_t upper) const
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limit = upper;
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// cerr << "== limit set to end of request @ " << limit << endl;
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} else {
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// cerr << "== limit set to next metric @ " << (*i)->frame() << endl;
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// cerr << "== limit set to next meter section @ " << (*i)->frame() << endl;
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limit = (*i)->frame();
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}
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@ -1486,22 +1490,22 @@ TempoMap::get_points (framepos_t lower, framepos_t upper) const
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// << " beat frame @ " << beat_frame << " vs. " << limit
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// << endl;
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if (beat > ceil(divisions_per_bar) || i != metrics->end()) {
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if (beat > ceil(divisions_per_bar) || (i != metrics->end() && dynamic_cast<MeterSection*>(*i))) {
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/* we walked an entire bar. its
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important to move `current' forward
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by the actual frames_per_bar, not move it to
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an integral beat_frame, so that metrics with
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non-integral beats-per-bar have
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their bar positions set
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correctly. consider a metric with
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9-1/2 beats-per-bar. the bar we
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just filled had 10 beat marks,
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but the bar end is 1/2 beat before
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the last beat mark.
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And it is also possible that a tempo
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change occured in the middle of a bar,
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so we subtract the possible extra fraction from the current
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/* we've arrived at either the end of a bar or
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a new meter marker.
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its important to move `current' forward by
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the actual frames_per_bar, not move it to an
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integral beat_frame, so that metrics with
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non-integral beats-per-bar have their bar
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positions set correctly. consider a metric
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with 9-1/2 beats-per-bar. the bar we just
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filled had 10 beat marks, but the bar end is
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1/2 beat before the last beat mark. And it
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is also possible that a tempo change occured
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in the middle of a bar, so we subtract the
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possible extra fraction from the current
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*/
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if (beat > ceil (divisions_per_bar)) {
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@ -1516,7 +1520,6 @@ TempoMap::get_points (framepos_t lower, framepos_t upper) const
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bar++;
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beat = 1;
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}
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}
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/* if we're done, then we're done */
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@ -1546,6 +1549,8 @@ TempoMap::get_points (framepos_t lower, framepos_t upper) const
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frames_per_bar = meter->frames_per_bar (*tempo, _frame_rate);
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beat_frames = meter->frames_per_division (*tempo, _frame_rate);
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// cerr << "New metric with beat frames = " << beat_frames << " bar = " << frames_per_bar << endl;
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++i;
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}
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