Deflate config comparison
Nathan Moinvaziri edited this page Dec 13, 2021
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2 revisions
The deflate configuration table used in zlib-ng is different than what is used in zlib. Due to this difference, the compression speed and ratio at each compression level will vary compared to zlib. These differences are important to note when doing performance comparisons between zlib-ng and zlib or other zlib forks.
| Level | Good length | Max lazy | Nice Length | Max Chain | Algorithm |
|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | Store |
| 1 | 4 | 4 | 8 | 4 | Deflate quick (Intel) |
| 2 | 4 | 5 | 16 | 8 | Deflate fast (Zlib) |
| 3 | 4 | 6 | 32 | 32 | Deflate fast (Zlib) |
| 4 | 4 | 4 | 16 | 16 | Deflate medium (Intel) |
| 5 | 8 | 16 | 32 | 32 | Deflate medium (Intel) |
| 6 | 8 | 16 | 128 | 128 | Deflate medium (Intel) |
| 7 | 8 | 32 | 128 | 256 | Deflate slow (Zlib) |
| 8 | 32 | 128 | 258 | 1024 | Deflate slow (Zlib) |
| 9 | 32 | 258 | 258 | 4096 | Deflate slow (Zlib) + fast-zlib changes |
| Level | Good length | Max lazy | Nice Length | Max Chain | Algorithm |
|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | Store |
| 1 | 4 | 4 | 8 | 4 | Deflate fast (Zlib) |
| 2 | 4 | 5 | 16 | 8 | Deflate fast (Zlib) |
| 3 | 4 | 6 | 32 | 32 | Deflate fast (Zlib) |
| 4 | 4 | 4 | 16 | 16 | Deflate slow (Zlib) |
| 5 | 8 | 16 | 32 | 32 | Deflate slow (Zlib) |
| 6 | 8 | 16 | 128 | 128 | Deflate slow (Zlib) |
| 7 | 8 | 32 | 128 | 256 | Deflate slow (Zlib) |
| 8 | 32 | 128 | 258 | 1024 | Deflate slow (Zlib) |
| 9 | 32 | 258 | 258 | 4096 | Deflate slow (Zlib) |