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Serialized bandlet tree IDs
The frequency space data of the bandlets is generally Huffman encoded. There are two tree sets, which will be called tree set A and tree set B. Each of the tree sets consists of 8 trees for each quantizer (except quantizer 0 which means that no data is present). Some of the trees are duplicate.
As opposed to the bandlet levels, which are stored for all bandlets up to the last bandlet with a non-zero quantizer, Tree IDs are not stored for bandlets with a zero quantizer at all, even if the zero quantized bandlet is followed by a bandlet with a non-zero quantizer.
The tree choice may either be complete (each bandlet chooses one of the eight trees for it's quantizer) or restricted (each bandlet chooses one of the four most common trees for it's quantizer). The choice between complete or restricted selection is global for the whole substream, not just for the channel! Thus the bit is not descibed here, in the per-channel tree choice data, but in the parent page substream data.