When I use Avidemux the program does not start maximized and when I try to maximize it nothing happens. I am using Avidemux 2.6.13 from Debmultimedia repositories.
Which window manager are you using? Avidemux won't start maximized, but the window should be maximisable, both with the deprecated Qt4 and the current Qt5 GUI (by the way, Qt4 GUI has a couple of issues (http://avidemux.org/smif/index.php/topic,16955.0.html) less in comparison with the Qt5 one, especially related to using in a maximized window).
Try recent, sep 11 2016, universal (linux) app: http://www.avidemux.org/nightly/appImage/
No install just run, if not running check properties and allow to run.
linux app info: http://appimage.org/
or if you're on 64-bit you could try avidemux Cli/Qt5 2.6.13 64-bit deb download ubuntu 16.04.1 LTS (http://avidemux.org/smif/index.php/topic,17019.0.html)
or you could build yourself:
- Compiling Avidemux 2.6.x (http://www.avidemux.org/admWiki/doku.php?id=build:install_2.6)
- avidemux 2.6.12 Compiling Avidemux on Ubuntu 16.04.1 LTS (http://avidemux.org/smif/index.php/topic,16750.0.html) this should be a similar approach for debian
The universal Avidemux maximizes properly. I will send the bug to the maintainer of the deb-multimedia repositories.