Doesn't mean the codec is better. I assure you mpeg4/divx is a much better codec with better algorithms for compressing with less loss of quality & for a smaller size. The larger/later the mpeg version the better the algorithm. I think you'll find the wmv codec loses more in quality in some regards be that motion compression, colour, resolution, lossy side FX, etc. That's why professionals stay a long way away from wmv. lol
And not forgetting m4a is roughly so to speak arguably mpeg4 audio.