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 Raw   ████████████████████████████████████ 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 Raw   ████████ 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 Raw	4,541 bytes	99.5%
LZ4 Frame	7,057 bytes	99.3%
Snappy	47,468 bytes	95.3%

Feature Matrix

Feature	Zstd	LZ4	LZ4 Raw	Snappy	Gzip	Brotli	Zlib
Streaming	✅	✅	❌	❌	✅	✅	✅
Dictionary	✅	❌	❌	❌	❌	❌	✅
Checksum	✅	✅	❌	❌	✅	❌	✅
Auto-detect	✅	✅	❌	✅	✅	❌	✅
Zero-copy	❌	✅	✅	✅	❌	❌	❌
Pure Zig	❌	✅	✅	✅	❌	❌	❌

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 Raw
• Web compatibility: Gzip or Brotli
• Real-time messaging: Snappy

Decision Tree

┌─ Need maximum speed?
│  ├─ Yes → LZ4 Raw (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