VSTI rendering, please confirm

[valley]

I am not so sure about that, see here

Is it actively shifting the audio file one sample leftwards though, or is it just forgetting to render the first sample? Also, even if it is shifting the audio file, is it consistent?

It is only a 'timing' problem if the audio is shifted in a manner that is not constant.

Otherwise it's a rendering bug, which whilst still a problem, does not necessarilly mean that Tracktion's timing is faulty.

[Samb]

Is it actively shifting the audio file one sample leftwards though, or is it just forgetting to render the first sample?

Both, except around the 8 minutes 32 mark and later.

Also, even if it is shifting the audio file, is it consistent?

Nope. Before 8'31" it is consistently early every time. Around 8'32" it is seemingly random. After 8'33" it works as it should.

It is only a 'timing' problem if the audio is shifted in a manner that is not constant.

That'll make it a 'timing' problem then.

Otherwise it's a rendering bug, which whilst still a problem, does not necessarilly mean that Tracktion's timing is faulty.

Yep. I think what's happening is that T is forgetting to render the first sample, but time-stamping the bwav correctly, except around 8'32" it makes more of an effort to get it right - not always succeeding - and later it actually succeeds in getting it right.

Why 8'32" is so special I have no idea.