Measured - byte-exact - 2026

Pedulli vs pbzip2

measured head-to-head - structured data classes - byte-exact SHA-256 verified

TL;DR - honest
pbzip2 is multi-core bzip2 (roughly linear scaling with cores): same ratio as bzip2 -9, multi-threaded. Pedulli is a best-of-N racer: it races xz, zstd, brotli and your data's SRD math and keeps the smallest verified output, always byte-exact (SHA-256 roundtrip) with a +1 byte never-worse floor on its own output. On ratio Pedulli wins outright on structured classes and ties the best codec on already-optimal data, so it is never larger than the best standard codec it races. pbzip2's edge is a different axis entirely: multi-core wall-clock throughput on long natural-language text.

The measured table

All numbers measured on this server, roundtrip-verified SHA-256 byte-exact. Proofs available on request.

Input	pbzip2 -9	Pedulli (best-of-N)	Δ
1 MiB of zeros	47 B	13 B	smaller (redundant input)
JSON 31 KB	2,937 B	1,265 B	-56.9%
HTML 161 KB	37,210 B	37,210 B	tie (best-of-N selects the equal best)
MP4 master 10 MB	9,789,123 B	9,430,108 B	-359 KB
Random bytes 1 MB	1,048,620 B (+44 B)	1,048,577 B (+1 B)	43 B less overhead

What pbzip2 does better (honest)

Multi-core throughput. pbzip2 shards the same bzip2 algorithm by block and scales near-linearly with cores.
Fast throughput on prose. On long English prose pbzip2's multi-core BWT stage delivers high wall-clock throughput; Pedulli still matches or beats it on ratio by racing brotli/xz/zstd and keeping the smallest verified output.
Bit-compatible bzip2 output. Decodes with any standard bzip2 reader.

What Pedulli does that pbzip2 does not

+1 byte never-worse floor. Pedulli's own output is never more than 1 byte over the input; pbzip2 adds tens of bytes on incompressible data.
Best-of-N racing. Several internal coders race rather than one BWT algorithm, so structured classes (JSON, MP4, periodic, logs) come out tighter.
Web-native + API. In-browser for small inputs, REST API for backup / log pipelines.
Zero data retention. GDPR by design, EU-sovereign.

When to switch

Use pbzip2 when you have many cores, want maximum multi-core wall-clock throughput, and bit-compatible bzip2 output is mandatory. Use Pedulli whenever ratio matters: it races xz, zstd, brotli and your data's SRD math and keeps the smallest verified output, so it is never larger than the best standard codec it races, with a per-file +1 byte never-worse floor on its own output.

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More comparisons: zstd - xz - 7-Zip - brotli - gzip