[Mp4-tech]Help on MPEG-4 Visual issures

[Michael xjb]

Hi,Experts
Recently I begin to study the MPEG-4 Visual and need to design an
Simple Profile codec based on MPEG-4 visual.
I try to read through the standard document(ISO/IEC JTC 1/SC 29/WG 11
N 3056),but found it is too difficult for me to
understand.The document seems to pay much attention on the bitstream
syntax that encoder and decoder must conform,and does not care on how
to implement it.
Also I could not find detailed and specific tools that are supported
by Simple Profile.In "h.264 and MPEG-4 video compression" book(Iain
Richardson),it is said that simple profile support (I-VOP,P-VOP,short
header,compression efficiency tools,transmission efficiency tools) but
with no further explain.
So,are there some other tools that also supported by Simple Profile?I
visit the mpeg.nist.gov web but could not find related documents that
have detailed description and specification on thoes items.Are there
any useful documents?
There are another problem that also confusing me.In the "h.264 and
MPEG-4 video compression" book,it is said that the short header mode
enables the direct compatibility between MPEG-4 Simple Profile and
H.263 baseline.What is the relationship between the two ones?Does it
means all the tools and feature provided by H.263 baseline also
supported by MPEG-4 Simple Profile?
I am freshman on MPEG-4 visual,any help will be great for me.Please
give me some advise,thanks in further