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temporal: workaround (perhaps temporary) for rounding issues in ::midi_clock_beat_at_or_after()

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This commit is contained in:
Paul Davis 2023-10-22 16:10:53 -06:00
parent 4228fce86b
commit b40513ff7d
1 changed files with 17 additions and 3 deletions
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20
libs/temporal/tempo.cc
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@ -4404,8 +4404,9 @@ TempoMap::midi_clock_beat_at_or_after (samplepos_t const pos, samplepos_t& clk_p
*
* from http://midi.teragonaudio.com/tech/midispec/seq.htm
*/
Temporal::Beats b = (quarters_at_sample (pos)).round_up_to_beat ();
superclock_t sc (samples_to_superclock (pos, TEMPORAL_SAMPLE_RATE));
TempoPoint const & tp (tempo_at (sc));
Temporal::Beats b = (tp.quarters_at_sample (pos)).round_up_to_beat ();
/* We cannot use
* clk_pos = sample_at (b);
@ -4422,7 +4423,20 @@ TempoMap::midi_clock_beat_at_or_after (samplepos_t const pos, samplepos_t& clk_p
*/
clk_beat = b.get_beats () * 4 ; // 4 = 24 / 6;
TEMPO_MAP_ASSERT (clk_pos >= pos);
/* It can happen (mostly due to odd plugin latency) that the @p pos
* argument is a few samples past the audio time of the current
* beat. For example, beat 20 @ 120 bpm @ 44100Hz would be at sample
* 441000 but the process() call that gets us here might start at
* 441002. Check if the error is more than 1 tick at the relevant
* tempo, and if so, round up the start (@p pos)
*/
if (clk_pos < pos) {
samplecnt_t one_tick_in_superclocks (tp.superclocks_per_note_type_at (timepos_t (sc))/ ((tp.note_type() * 1920) / 4));
if (abs (clk_pos - pos) < superclock_to_samples (one_tick_in_superclocks, TEMPORAL_SAMPLE_RATE)) {
clk_pos = pos;
}
}
}
/******** OLD STATE LOADING CODE SECTION *************/