pb finding video decoder

[topinrouen]

Hello

I use Avidemux on windows7 for several months. Very recently, I have a problem.
When I open Avidemux, it cant'find the "video decoder". It is written "XXX" whereas before there was "lavcodec" instead.
I've made a screen capture.


How can i make Avidemux find the right decoder ?

[mean]

What codec is it ?