I generally use videos taken from Fraps and convert/encode them to an avi with x264 video (2 Passes & target bitrate of 200) and mp3 audio (usually 20 kBits/s, 8000 Hz, Stereo) using VirtualDub.

The guide here (the section under Two Pass): http://teek.info/guides/video/x264encode.html is pretty much what I do manually each time.

Is there a way to automate this process? I'm aware that Avisynth could be used but I don't know how to write such a script nor do I know how to make a generic script, as from all the examples I've seen, you have to specify which video file name exactly each time. Is there a way to simply pick the source file each time?

I've googled around and found this vbs script: http://www.ericphelps.com/scripting/samples/VirtualDub/index.html but it doesn't seems to really work.

Can anyone can help me write a simple script (if that's indeed what I need) or point me in the direction of a simple program that can do the conversion/encode I need?

I've tried AutoMKV and StaxRip but both seems to be far more complicated than this process needs to be, I can do it faster manually with VirtualDub. Also neither seem to be able for me to specify a bitrate, instead they both ask for a target file size which is not what I want as I don't have any specific file size in mind.

Much thanks.