I use Total Video Converter. It can convert video to MP4/MKV/WMV/AVI and other popular formats such as: H.264/MPEG-4 AVC, FLV, MPEG-1, MPEG-2, 3GP, 3GPP, DivX, Mov, M4V, DivX, XviD, ASF, SWF, VOB, DV, Super VCD(NTSC, PAL, SECAM), VCD(NTSC, PAL, SECAM) , DVD(NTSC, PAL, SECAM) and HD video.
It is also multifunctional such as video trim, effect, crop and watermark.
For more information, here:
Hope it helped.