# COMPRESSION_LZRAVEN The LZRAVEN compression algorithm, which is recommended for high-compression ratio with fast decoding on Apple platforms. ``` var COMPRESSION_LZRAVEN: compression_algorithm { get } ``` ## Discussion LZRAVEN is the Apple high-compression algorithm, designed to replace [`COMPRESSION_LZMA`](/documentation/Compression/COMPRESSION_LZMA) across Apple platforms. It combines LZ77 with modern entropy coding, adaptive context-sensitive modeling, and near-optimal parsing to often achieve a slightly better compression ratio than [`COMPRESSION_LZMA`](/documentation/Compression/COMPRESSION_LZMA). LZRAVEN uses an 8 MB dictionary and encodes faster than [`COMPRESSION_LZMA`](/documentation/Compression/COMPRESSION_LZMA) while decoding 3x faster on Apple silicon, where the decoder leverages vector units to process multiple symbols per operation. An LZRAVEN-encoded buffer begins with a stream header that encodes global encoder parameters, defines the quantized size of the LZ dictionary, and provides reserved feature flags for future extensions. The stream header is followed by a sequence of compressed or uncompressed blocks that are terminated by an empty block. Each block begins with a header that encodes the block’s compressed size and feature flags. A block can be either compressed or stored uncompressed when compression would provide no benefit. LZRAVEN is practical for latency-sensitive workloads where [`COMPRESSION_LZMA`](/documentation/Compression/COMPRESSION_LZMA) decode speed would be prohibitive. LZRAVEN is available through the buffer API only — [`compression_encode_buffer(_:_:_:_:_:_:)`](/documentation/Compression/compression_encode_buffer(_:_:_:_:_:_:)) and [`compression_decode_buffer(_:_:_:_:_:_:)`](/documentation/Compression/compression_decode_buffer(_:_:_:_:_:_:)). The decoder requires approximately 36 KB of scratch memory, making it well suited for memory-constrained environments. > Note: The `COMPRESSION_LZRAVEN` algorithm is available in version 27 or later of Apple operating systems. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)