levels in MPEG-4 amp; H.263 definition, something, products, profile, someone

andy

Hi,
  When i browse website, i used to see someone mentioned their products support MPEG-4 simple profile level 0b/10b and H.263 profile 0 level 45. But in the spec i have (ISO/IEC 14496-2:2001 and ITU-T H.263(04/2001)), i couldn't find the definition of these levels. Am i missing something?? Could someone kindly explain to me what are the definitions of these levels (level 0b/10b and level 45)??? Thanks a lot!!!

Carmiyu