envelop point Y coordinate trees

These trees are built as canonical huffman trees. Remember that negative values are 2's complement encoded and thus appear after the positive values in the trees.

• 0: not possible
• 1: 2 bits
• 2, 3: 3 bits
• 4..7: 4 bits
• 8..11: 5 bits
• 12..15: 6 bits
• 16..31: 8 bits

• 0: not possible
• 1: 4 bits
• 2..6: 3 bits
• 7, 8: 4 bits
• 9, 10: 5 bits
• 11..13: 6 bits
• 14, 15: 7 bits
• 16..31: 8 bits

• -16..-4: 7 bits
• -3, -2: 6 bits
• -1: 4 bits
• 0: 1 bit
• 1, 2: 4 bits
• 3, 4: 5 bits
• 5..8: 6 bits
• 9..15: 7 bits

• -16..-7: 6 bits
• -2..-6: 5 bits
• -1: 4 bits
• 0: 2 bits
• 1: 4 bits
• 2..7: 5 bits
• 8..15: 6 bits

• -16..-5: 5 bits
• -4..-3: 4 bits
• -2..-1: 5 bits
• 0: 4 bits
• 1..4: 5 bits
• 5..10: 6 bits
• 11..15: 5 bits