3.1.9.1 RDP 8.0

RDP 8.0 lossless compression is a specialization of the Lempel-Ziv ("LZ77") technique ([SAYOOD] section 6.2.3.2.2) paired with static Huffman encoding ([SAYOOD] sections 4.1 to 4.7). It is most-easily explained by detailing the operation of a decompressor. A compliant data compressor MUST encode input data, and a compliant data decompressor MUST decode compressed data, according to the format defined in section 3.1.9.1.2 and its subsections.

Any given input data could have many valid but different compressed representations. Whether the "compressed" representation is actually smaller than the original is dependent on the characteristics of the input data and on the compressor implementation. A compliant decompressor MUST accept any conforming compressed encoding and produce output that exactly matches the original input to the compressor. This document specifies at least one way to decode RDP 8.0 compressed data, although numerous implementation approaches are possible.