[XviD-devel] problem with xvid understanding

Christoph Lampert chl at math.uni-bonn.de
Fri Oct 31 11:00:58 CET 2003


On 31 Oct 2003, rakesh  kothari wrote:

> hi all,
> 
> I am new to xvid and mpeg-4. I was wondering whether it is possible
> with xvid to exactly know which frame is I-Frame or P-Frame.And for
> that matter which part of the xvid code helps us to identify them.

What do you mean about "know"? After encoding or decoding a frame,
you get a parameter returned which tells you which VOP time a frame
was: I,P or B. 
If you want to determine yourself how to encode the next frame, that
you can do by passing the right "intra" flag to the encoder. 

> Also can we get to know about individual objects in a frame(object
> descriptors), which can be useful in getting to know whether a object
> is useful or not.

XVID only support Simple Profile and Advanced Simple Profile, so there are
no multiple objects, only one fullsize rectagular object per frame.

> As far as I know Mpeg-4 codes each object in a frame. Are I-Frame
> consist of individual objects or multiple objects.
> 
> These questions might sound naive but still I would be very thankful
> if I could get answer of these.
> 
> Is there any online tutorial for MPEG-4.

Yes, lots of them. A good starting point is the 
"resources" section of  www.m4if.org 

gruel




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