Comment 1 for bug 1223555

To help narrow down the problem, please can you try speeding up your videos using ffmpeg & melt:

for ffmpeg, something like this:

ffmpeg -i input.mkv -filter:v 'setpts=0.5*PTS' output.mkv

for melt, I don't know the exact cmd line syntax to use, so create a simple project in OpenShot that has the problem. Then use the menu item File>Export XML to create an xml file that can be parsed by melt, such as:

melt filename.xml

By doing this, we can see if the problem is in ffmpeg, MLT or OpenShot.