CurrentPositionInfo.timeInSamples and tempo changes in ableton live

It seems that the timeInSamples given by Live is wrong when the tempo changes (tested with vst2).
When getting timeInSamples in processBlock(), I expect it to increase by numSamples, whether the tempo changes or not.
But the tempo changes seem to make some timeInSamples jumps.

Am I missing something, or is it most likely an ableton bug?

diff.txt (1,5 Ko)

frameSize 512
timeInSamplesDiff 512
frameSize 512
timeInSamplesDiff -1261
frameSize 512
timeInSamplesDiff 512
[…]
frameSize 512
timeInSamplesDiff -1305
frameSize 512
timeInSamplesDiff 512

As someone who just implemented variable tempo in their DAW (which is a nightmare) this is really fascinating to see.

I feel confident saying this is probably a Live bug, perhaps with the time->tempo mapping algorithm they’re using giving back the wrong time (maybe they’re going time->tempo->time->samples?).

1 Like

Wow, that’s interesting. This definitely looks like an Ableton bug. JUCE’s timeInSamples comes pretty much straight from VST2’s audioMasterGetTime opcode and JUCE does not do anything special with this number - it just passes it on to you.

1 Like

I’ve reported this bug to Ableton. Let’s wait and see what they say…

3 Likes

Ableton has a new bug reporting system. Can you let me know exactly which Live version (i.e. x.x.x) you encountered this bug. Which OS were you using? 32-bit or 64-bit?

Is that public? I like when companies have a simple support email or a public way to report bugs…

anyway:
live lite 9.6.1 - macOS 10.3.3 64 bit

@lalala Yes it is. It might be better that you file the bug. Let me know the ticket number so that I can make sure that it is escalated.

https://ableton.centercode.com/key/developer_tickets