[XviD-devel] about rate control mechanism

[zhouxiao]

Hi, everyone,
Can someone tell me something about the rate control mechanism used in XviD ?

Now I am using XviD  to  encode the realtime scene collected by a  camera. 
And I found that no matter how much the scene changes, the bitstream size for a fixed time interval is almost invariable. That is, If user specify the target bitrate is 900kbps, then, rate control can only maintain
the real bitstream size approximately on the level of 900kbs .                                          
But maybe in some application, users could expect the real bitstream size can vary acording to the scenes' change, if the scene changes little, the bitrate is low, and if changes much, bitrate increases but cannot exceed 900kbps. That is, we need a rate adjusting mechanism which can ensure the real bitrate always under or on the level of target bitrate , not the rate control used in XviD which can only on the level of target bitrate.

Can someone help me on this topic? 

   

　　　　　　　　　2003-01-16