Reaper reports incorrect position to VST plugins at certain tempo's.

[Pollo]

VST plugins can query the host for current time information which the host returns in a VstTimeInfo structure. At certain tempo's Reaper reports incorrect values to the plugin. Noticeably in the values for ppqPos and samplePos, both members of the VstTimeInfo structure.

I observed this for instance at a tempo of 117 BPM. I suspect that it has to do with the fact that at that tempo the number of samples in one beat is not an integer value.

The errors in the time position information make it impossible to sync to the host at these tempo's.

I can provide more information if needed.

[Pollo]

More information: it is entirely possible that I just don't fully understand how it should work but I'm observing the following behaviour that I can't explain. I am debugging a VST plugin using the following code:

void processReplacing(double **inputs, double **outputs, VstInt32 sampleFrames)
{
VstTimeInfo* pInfo = getTimeInfo(0);
if (pInfo) {
if (pInfo && (pInfo->flags & kVstTransportChanged) && (pInfo->flags & kVstTransportPlaying)) {
// set breakpoint here
// it will hit only the first time that playback starts
}
}


I have a project set up. Plugin is inserted on a track, nothing else. BPM = 117. I have a ruler offset of 4 bars, so the first bar is -3, then -2, etc. Bar 1 is actually the fourth bar of the project. I set the playback cursor at bar 1 and start playback and then look at the values I receive from getTimeInfo(). This is what I get:

samplePos = 5.4999999999736815
ppqPos = 15.999993197278911

I would expect to see this:

samplePos = 0.0000000000000
ppqPos = 16.0000000000000

[Xenakios]

I think you will just have to accept the ppqPos is slightly off and quantize it yourself to the closest beat division. Is the behavior different in other hosts?

[schwa]

https://forum.cockos.com/showthread.php?t=216973

[EvilDragon]

Wow, same thread, same person, same question.

[Pollo]

Originally Posted by EvilDragon

Wow, same thread, same person, same question.

same person, yes. same thread, no (how could it be?). same question, sort of.

[Pollo]

The problem is solved. This can be closed.

schwa, thanks for the clarification.