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Debug loop range squishing

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When the loop-range is defined in BeatTime, the disk-reader encounters
rounding issues due to time-domain mismatches.

With a simple session fixed BPM at 120,  48kHz.
looping 1 bar exactly 2 sec at the start of the session:
```
 Range::squish start: b0 end: b7680 squish: a113554560
 Range::squish using modulo:       b45 = a661500
 Range::squish using modulo in TD: a5760
 Range::squish using earlier():    a658560
```
The correct answer is a113554560 - 2 * 56448000 [SC/sec] = a658560

Calculating the modulo iteratively is not great, however usually
only one iteration is required.
This commit is contained in:
Robin Gareus 2022-06-28 03:01:41 +02:00
parent 65956407bb
commit ee350362d3
Signed by: rgareus
GPG Key ID: A090BCE02CF57F04
2 changed files with 43 additions and 6 deletions
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42
libs/temporal/range.cc
View File

@ -16,6 +16,10 @@
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef NDEBUG
#include <sstream>
#endif
#include "temporal/range.h"
using namespace Temporal;
@ -96,6 +100,44 @@ Range::subtract (RangeList & sub) const
return result;
}
timepos_t
Range::squish (timepos_t const & t) const
{
if (t < _end) {
return t;
}
#if 1
#ifndef NDEBUG
std::stringstream dbg;
dbg << "Range::squish start: " << _start << " end: " << _end << " squish: " << t << "\n";
#endif
timepos_t rv = t;
while (rv >= _end) {
rv = rv.earlier (length ());
}
#ifndef NDEBUG
timepos_t sq = _start + (_start.distance (t) % length());
dbg << "Range::squish using modulo: " << sq << " = ";
sq.set_time_domain (t.time_domain());
dbg << sq << "\n";
timepos_t start = _start;
start.set_time_domain (t.time_domain());
timepos_t sqt = start + (start.distance (t) % length());
dbg << "Range::squish using modulo in TD: " << sqt << "\n";
dbg << "Range::squish using earlier(): " << rv << "\n";
std::cout << dbg.str ();
#endif
return rv;
#else
return _start + (_start.distance (t) % length());
#endif
}
template<> OverlapType Temporal::coverage_exclusive_ends<int64_t> (int64_t sa, int64_t eaE, int64_t sb, int64_t ebE)
{
/* convert end positions to inclusive */

7
libs/temporal/temporal/range.h
View File

@ -169,12 +169,7 @@ class LIBTEMPORAL_API Range {
* looping). If the argument is earlier than or equal to the end of
* this range, do nothing.
*/
timepos_t squish (timepos_t const & t) const {
if (t >= _end) {
return _start + (_start.distance (t) % length());
}
return t;
}
timepos_t squish (timepos_t const & t) const;
/* end is exclusive */
OverlapType coverage (timepos_t const & s, timepos_t const & e) const {