找 google 大神看看便知道了:
http://mf.creations.nl/avs/filters/MPEG2Dec3.html

idct : 1 to 5.
iDCT : iDCT algo used.
-0 : Default value (in .d2v file)
-1 : 32 bit MMX
-2 : 32 bit SSEMMX
-3 : 64 bit FPU
-4 : 64 bit IEEE-1180 Reference
-5 : 32 bit SSE2 (for P4)
default : 0

idct=5 即是 Intel P4 cpu

cpu : 0 to 6.
DivX decoder like cpu level setting. - 0 : No PP
- 1 : DEBLOCK_Y_H
- 2 : DEBLOCK_Y_H, DEBLOCK_Y_V
- 3 : DEBLOCK_Y_H, DEBLOCK_Y_V, DEBLOCK_C_H
- 4 : DEBLOCK_Y_H, DEBLOCK_Y_V, DEBLOCK_C_H, DEBLOCK_C_V
- 5 : DEBLOCK_Y_H, DEBLOCK_Y_V, DEBLOCK_C_H, DEBLOCK_C_V, DERING_Y
- 6 : DEBLOCK_Y_H, DEBLOCK_Y_V, DEBLOCK_C_H, DEBLOCK_C_V, DERING_Y, DERING_C
(Y=luma C=chroma, H=horizontal V=vertical)
default : 0

Deblock 即是減少影像有一格一格的情況發生, luma 和 chroma 是兩個不同的 colorspace... (好像是這樣...)

iPP :
To use Field-Based Post-Processing.
it' better if you want to deinterlace
- True : Field based
- False : Image based (default)

這亦是影像優化, 不過如果你要 deinterlace 的話便用 iPP, 不用的話便不用 iPP...