Decompression of level 5 frames

Recorded run: long-20261109 (2026-11-09). CSV · Environment · Methodology and limits.

Level belongs to the C encoder that prepared the frame; decoders have no level setting. Both decoders restore the same bytes.

Median speed across 8 datasets

Median of per-dataset C mean time / decoder mean time ratios, with equal weight. Higher is faster; 1× matches C. No confidence interval is inferred for this across-dataset median.

Decoder	Median speed / C
zstd C	1.000×
mzstd	1.589×

Decompression by dataset at source level 5

Datasets are ranked by mzstd speed relative to C, highest first. Throughput counts restored bytes; empty input has latency only. Whiskers and intervals describe sampling uncertainty, not all host variation. Cold APIs include allocation and disposal. C reads the frame’s content size and decodes into a buffer of exactly that size; mzstd returns its own vector.

empty

Empty input; measures API overhead.

9 compressed → 0 restored bytes; compressed / original: undefined.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	2.194	2.127–2.263	—	1.000×
mzstd	0.04339	0.04148–0.04542	—	50.557×

tiny-text

44-byte quick-brown-fox sentence.

53 compressed → 44 restored bytes; compressed / original: 120.455%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	2.002	1.957–2.064	20.96	1.000×
mzstd	0.0513	0.04955–0.05327	818.03	39.030×

random-64k

64 KiB prefix of the deterministic pseudorandom corpus.

65,546 compressed → 65,536 restored bytes; compressed / original: 100.015%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	2.969	2.91–3.035	21,052.20	1.000×
mzstd	0.9479	0.9289–0.9696	65,935.79	3.132×

binary-64k

64 KiB of structured binary bytes: ((i / 16) XOR i) modulo 256.

1,270 compressed → 65,536 restored bytes; compressed / original: 1.938%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	6.549	6.279–6.831	9,542.76	1.000×
mzstd	4.059	3.981–4.163	15,396.37	1.613×

repeated-1m

1 MiB of repeated a bytes.

50 compressed → 1,048,576 restored bytes; compressed / original: 0.005%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	14.48	14.16–14.85	69,069.47	1.000×
mzstd	9.253	9.119–9.411	108,073.49	1.565×

random-1m

1 MiB of deterministic xorshift64 pseudorandom bytes.

1,048,609 compressed → 1,048,576 restored bytes; compressed / original: 100.003%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	19.86	19.64–20.1	50,345.47	1.000×
mzstd	17.19	17.03–17.37	58,159.58	1.155×

text-1m

Alice text repeated cyclically to 1 MiB.

54,185 compressed → 1,048,576 restored bytes; compressed / original: 5.167%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	121	117.3–125	8,264.80	1.000×
mzstd	120	117.6–123	8,331.92	1.008×

alice29

Alice in Wonderland text from the Canterbury corpus (testdata/alice29.txt).

53,372 compressed → 152,089 restored bytes; compressed / original: 35.093%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	92.75	91.47–94.26	1,563.77	1.000×
mzstd	99.14	97.16–101.5	1,462.98	0.936×

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mzstd