Mpeg4 Object Tracking

[Aero2004]

I'm complete newbie in Video programming... however, I am assigned a project to do video tracking in Mpeg4... now i hav the C++ code of Mpeg4 encoder and decoder... but after reading thru the code to no avail...
I would like to know... which part of the codec should I focus on? the decoder or encoder? wat i need to show is just that i can capture an object, e.g.: a guy in the video, and tracking all his movement along the video...
thanks in advanced

[Aero2004]

It's me again... The encoder that i'm using accepts .yuv file and converts it into .cmp file.. and the decoder only decodes the .cmp file into .yuv file back... the .yuv is .mpeg4 standard file? I'm wondering whether I'm using the correct encoder.. because initially what I expect to get from an encoder is the encoder will encode normal .avi file into .mpg4 ext and the decoder will decode the .mpg4 file and play it... is there such codec available and is it open source code with documentation? if yes, may i know where to download it?
Thank you...

[major]

YUV has nothing to do with MPEG-4. If you don't study these formats first, you'll probably encounter some difficulties in programming anything which is going to directly process data coded in such formats. Also, this forum is not the good place to ask this question. Try Google first with "YUV format" and "mpeg-4 format description" for some kick-off readings.