06-10-2012, 03:19 PM
SWE 423: Multimedia Systems
StNotes08d.ppt (Size: 1.28 MB / Downloads: 88)
Predictive Coding
Predictive coding simply means transmitting differences
Predict the next sample as being equal to the current sample
More complex prediction schemes can be used
Instead of sending the current sample, send the error involved in the previous assumption
Predictive Coding: Why?
The idea of forming differences is to make the histogram of sample values more peaked.
In this case, what happens to the entropy?
As a result, which is better to compress?
Lossy Predictive Coding: DPCM
The distortion is the average squared error
To illustrate the quality of a compression scheme, diagrams of distortion vs. the number of bit levels used are usually shown
Quantization used
Uniform
Lloyd-Max
Does better than “Uniform”