02
Encoder
Source on the left, the tree in the middle, what the decoder holds on the right. Click a row (or its label) to encode that level.
click to average
averaging now
encoded
parent → child
Run a level and every node in that row averages the pixels it covers, then stands in for them as one flat square. What leaves the encoder is not the average itself but its difference from the parent's average. The root has no parent, so it sends its average as is.
Source on the left, the tree in the middle, what the decoder holds on the right. Click a row (or its label) to encode that level.