XMedia Recode is simply my favorite video/audio converter software out there. It can convert multimedia files from just about any format to another.
Supported file formats include 3GP, AAC, AVI, DVD, FLV, H.264, MP3, MP4, MPEG, QuickTime, RMVB, WMA and many more. Aside from that, you can choose the output to match the brand and make of your digital audio/video player such as for iPod, iPhone, Zune, PSP, Sony Walkwan and also mobile phones such as Nokia, Blackberry and Motorola.
Moreover XMedia Recode features some basic filtering like changing the screen resolution, cropping, padding, color correction and deinterlacing. I find the volume correction setting particularly useful to increase the volume of the video files that I'm converting.
XMedia Recode lets you choose how it uses your CPU resources whether normal, high or idle which will affect how fast the processing is done. You can also set it to shutdown the computer automatically when it finishes.
XMedia Recode is available for free from the developer's website although donations is always welcomed. Don't be alarmed by the German language website, just hit download to get your copy. XMedia comes in standard standalone exe file and also in a portable version. Unfortunately XMedia Recode is only for Windows users. My other favorite cross-platform multimedia converter would be Handbrake.