Because h264 at 233mb is way better quality w/ avisynth if the encoder knows what 'he/she' is doing.
Thus this short brief table
--------------------------------------XVID @ 170mb /avg. with avg fansub is = 730-850 bitrate
--------------------------------------h264 @ 170mb /avg. with avg fansub is = 1080 bitrate about
so h264 at 233mb would be---around 1600 bitrate + filtering in said theory
But i base this off of a 23minute 14 second episode of anime with awarpsharp and convolution3d in h264 using b-frames as references on spatial and Exhaustive Search and RDO. But it depends..they are big because it results in more quality as said...though in some cases not true *cough* Power2all *cough* h264 *cough* in *cough* avi *cough* thinks * cough * mp4 *cough * was audio format *cough*
