If you are looking for a completely free, reliable desktop application to manage your media library, Format Factory is still a top contender.
It accepts virtually any source file and outputs to standard formats including MP4, AVI, MKV, FLV, and MOV.
Once the task is added to the queue, hitting "Start" begins the conversion process. The software supports multi-threading, meaning it can process multiple files simultaneously if the CPU allows. Why Version 5.9 Persists