Are there any powerful, error free paid software to edit Mp4 & avi files?

[seymoria]

1) Avidemux simply refuses to save many edited mp4 files on the points asked to it. The desirable time start and end points. (Pops up 'saved' and saves nothing. I understand its the key frame thing).
2) VirtualDub for 95% of cases cannot cut out a part exactly where asked for in the start (goes back many seconds earlier spoiling the saved piece).

Can you suggest some good and better performing / more powerful software (can be paid)?

Thank you.

[Baldrick]

You have already posted this. You need an editor with smart rendering. See
https://forum.videohelp.com/threads/362137-Virtualdub-not-keeping-frame-accuracy-during...=1#post2299457