How to trim videos?

[Selur]

Can not repodurce that here, would need step-by-step instructions and sample of a source that allows to reproduce this.

[Robbie303]

OK, I will investigate a bit more and come back about this to you.

Another thing I would like to mention (this subject is not trimming related though) is about the QTGMC Deinterlacing:
the deinterlacing analysis (5%) takes quite a lot of time, and I noticed that the CPU usage is always quite low, around 10%.
Wouldn't it be possible to speed-up the deinterlacing analysis?

[Selur]

Wouldn't it be possible to speed-up the deinterlacing analysis?

Not really, what makes the analysis slow is file access (jumping inside the file) speeds, splitting the analysis in different parallel calls would just make it worth.
Also, the analysis is just a heuristic, looking at the file manually is always better.