Optimizing MPEG2 Encoder in Adobe Media Encoder
After some deep Googling, I did find explanations for a few of these options:


  MPEG macroblock quantization level. Valid values are from 2 to 31. Low
  values of this variable mean higher quality and higher bitrate, so 2
  is the highest quality and 31 is the lowest quality.





  VBV buffer size in units of 16k bits. The meaning of this parameter is
  confusing because it is used to help predict if the MPEG decoder might
  suffer buffer overflows or underflows. VBV buffer over/under flows are
  more commonly a problem when in CBR mode. If significant artifacts are
  present in the generated movie, try increasing this parameter.


(http://vis.lbl.gov/NERSC/Software/express/help6.2/help/relnotes/mpeg.htm)


  Intra DC Precision: the MPEG-1 DC value is mandatory quantized to a
  precision of 8 bits. MPEG-2 introduced 9, 10, and 11 bit precision set
  on a picture basis to increase the accuracy of the DC component, which
  by very nature, has the most significant contribution towards picture
  quality. Particularly useful at high bit rates to reduce
  posterization. Main and Simple Profiles are limited to 8, 9, or 10
  bits of precision.


http://www.gadegast.de/frank/mpegfaq/mpe1736.html


  In MPEG-2 video, Intra DC Precision indicates the number of bits for
  quantized DC coefficients of intra-coded blocks; it takes one of the
  values of 8, 9, 10, or 11 bits. The more bits are used, the more
  precise quantization is achieved.


http://avs.kddilabs.jp/mpeg/mpcs/faqe.html