Codecs Overview

compressionz supports seven compression codecs, each with different characteristics. This page provides a high-level overview.

Codec Summary

Codec	Type	Speed	Ratio	Best For
Zstd	Dictionary	Very Fast	Excellent	General purpose
LZ4	LZ77	Fastest	Good	Speed-critical
Snappy	LZ77	Very Fast	Moderate	Real-time
Gzip	Deflate	Moderate	Good	Compatibility
Brotli	Dictionary	Slow	Best	Web assets
Zlib	Deflate	Moderate	Good	PNG, legacy

Compression Algorithm Families

LZ77-Based

How it works: Find repeated sequences, replace with (offset, length) pairs.

Codecs: LZ4, Snappy

Characteristics:

• Very fast compression and decompression
• Moderate compression ratios
• Simple implementation
• Low memory usage

Deflate-Based

How it works: LZ77 + Huffman coding for better ratios.

Codecs: Gzip, Zlib, Deflate

Characteristics:

• Good compression ratios
• Moderate speed
• Universal compatibility
• Established standard

Dictionary-Based

How it works: Pre-computed probability tables and advanced entropy coding.

Codecs: Zstd, Brotli

Characteristics:

• Excellent compression ratios
• Asymmetric (compression slower than decompression)
• Higher memory usage
• Modern algorithms

Performance Comparison

Throughput (1 MB Data)

Compression Speed (GB/s)
+------------------------------------------------------+
| LZ4 Block #################################### 36.6  |
| Snappy    ############################### 31.6       |
| Zstd      ############ 12.0                          |
| LZ4 Frame ##### 4.8                                  |
| Gzip      ## 2.4                                     |
| Brotli    # 1.3                                      |
+------------------------------------------------------+

Decompression Speed (GB/s)
+------------------------------------------------------+
| Zstd      ############ 11.6                          |
| Snappy    ######### 9.2                              |
| LZ4 Block ######## 8.1                               |
| LZ4 Frame #### 3.8                                   |
| Gzip      ## 2.4                                     |
| Brotli    ## 1.9                                     |
+------------------------------------------------------+

Compression Ratio

On mixed-pattern 1 MB data:

Codec	Compressed Size	Ratio
Brotli (best)	535 bytes	99.9%
Zstd	684 bytes	99.9%
Gzip	4,382 bytes	99.6%
LZ4 Block	4,541 bytes	99.5%
LZ4 Frame	7,057 bytes	99.3%
Snappy	47,468 bytes	95.3%

Feature Matrix

Feature	Zstd	LZ4 Frame	LZ4 Block	Snappy	Gzip	Brotli	Zlib
Streaming	Yes	Yes	No	No	Yes	Yes	Yes
Dictionary	Yes	No	No	No	No	No	Yes
Checksum	Yes	Yes	No	No	Yes	No	Yes
Auto-detect	Yes	Yes	No	Yes	Yes	No	Yes
Zero-copy	No	Yes	Yes	Yes	No	No	No
Pure Zig	No	Yes	Yes	Yes	No	No	No

Implementation Details

Codec	Source	Version	License
Zstd	Vendored C	1.5.7	BSD
Gzip/Zlib	Vendored C (zlib)	1.3.1	zlib
Brotli	Vendored C	Latest	MIT
LZ4	Pure Zig	-	Apache 2.0
Snappy	Pure Zig	-	Apache 2.0

Choosing a Codec

Quick Decision

• Default choice: Zstd
• Maximum speed: LZ4 Block
• Web compatibility: Gzip or Brotli
• Real-time messaging: Snappy

Decision Tree

+- Need maximum speed?
|  +- Yes -> LZ4 Block (if you track size) or Snappy
|  +- No -+
|         |
+- Need web compatibility?
|  +- Static assets -> Brotli
|  +- Dynamic content -> Gzip
|  +- No -+
|         |
+- Need streaming?
|  +- Fast + checksum -> LZ4 Frame
|  +- Best ratio -> Zstd
|  +- No -+
|         |
+- Default -> Zstd (best overall)

See Choosing a Codec for detailed guidance.

Codec Deep Dives

Learn more about each codec:

• Zstandard (Zstd) — Best overall balance
• LZ4 — Maximum speed
• Snappy — Real-time applications
• Gzip — Universal compatibility
• Brotli — Maximum compression
• Zlib & Deflate — Legacy formats