SPIHT Decoding
The decoder emulates the encoder.
- The decoder maintains exactly the same data structures as the encoder.
- When the decoder has popped the Z stack to examine a zero tree it receives a bit telling it whether the tree is significant. The decoder can then do the right thing.
- If it is significant then it does the decomposition.
- If it is not significant then it deduces a number of zeros in the current bit plane.