vcodec:
vbitrate: Specify bitrate (default: 800)

vb_strategy=<0 - 2> (pass one only) : strategy to choose between I/P/B-frames
mbd=<0 - 2>: Macroblock decision algorithm (high quality mode), encode each macro block in all modes and choose the best. This is slow but results in better quality and file size
mv0: Try to encode each MB with MV=<0,0> and choose the better one. This has no effect if mbd=0.
v4mv: Allow 4 motion vectors per macroblock (slightly better quality). Works better if used with mbd>0.
cmp=<0 - 2000>: Sets the comparison function for full pel motion estimation (default: 0)
trell: Trellis searched quantization. This will find the optimal encoding for each 8x8 block.
cbp: Rate distorted optimal coded block pattern. Will select the coded block pattern which minimizes distortion + lambda*rate. This can only be used together with trellis quantization.
dia=<-99 - 6>: Diamond type & size for motion estimation.
last_pred=<0 - 99>: amount of motion predictors from the previous frame