Decompression of level 16 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	1.453×

Decompression by dataset at source level 16

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	2.065	2.001–2.138	—	1.000×
mzstd	0.03809	0.03724–0.03915	—	54.227×

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	2.217	2.151–2.283	18.93	1.000×
mzstd	0.05089	0.04957–0.05241	824.62	43.570×

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	2.92	2.865–2.98	21,405.35	1.000×
mzstd	0.9004	0.894–0.9077	69,412.17	3.243×

repeated-1m

1 MiB of repeated a bytes.

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

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	14.21	13.97–14.52	70,356.23	1.000×
mzstd	9.748	9.483–10.03	102,583.68	1.458×

binary-64k

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

1,259 compressed → 65,536 restored bytes; compressed / original: 1.921%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	6.281	6.143–6.438	9,950.30	1.000×
mzstd	4.336	4.231–4.474	14,413.16	1.449×

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	19.28	19.18–19.38	51,870.23	1.000×
mzstd	17.27	17.07–17.49	57,900.78	1.116×

text-1m

Alice text repeated cyclically to 1 MiB.

49,924 compressed → 1,048,576 restored bytes; compressed / original: 4.761%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	117.6	113.1–122.8	8,504.21	1.000×
mzstd	116.9	115–119.1	8,553.42	1.006×

alice29

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

49,355 compressed → 152,089 restored bytes; compressed / original: 32.451%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	113.4	108.2–119	1,279.18	1.000×
mzstd	117.3	112.2–123	1,236.96	0.967×

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mzstd