Fig. 1 - Region shorter than the bar.

Community member Dustin Anstey has wrote asking about an issue where duplicated clips change length after extended duplication.

To demonstrate he created a quarter note length clip containing a kick drum sample and then duplicated across the timeline for around 4 minutes. Even though the region is cut to the grid, over time it starts to change length and pushes the entire track out of time.

Even more odd is the fact that sometimes it shortens the clip (fig 1) and at other times it lengthens the clip (fig 2). In all cases it’s only by a matter of samples, but it is still not correctly placing the audio.

Fig. 2 - Region longer than the bar.

We have tested this ourselves and can replicate the issue.

Some users suggest that this is the sample rounding feature in Pro Tools, however on tests in other DAWs (some a fraction of the cost of Pro Tools) and this issue does not occur.

DAWs tested: 

• Apple Logic Pro X v 10.0.6 - No drift with clip copied for 180 bars
• Reaper 4 - No drift with clip copied for 180 bars
• Steinberg Nuendo 6.02 - No drift with clip copied for 180 bars
• Propellehead Reason 7.1 - No drift with clip copied for 180 bars

Dustin also comments in his email “It also seems to be a bit worse with midi regions and it varies depending on how much delay compensation is happening.”

However when using the Loop function or the Paste Special/Repeat To Fill Selection workflows the audio maintains the correct length.

Discuss.