cmz 1.0 beta 5

cmz 1.0 beta 5 — WAV audio, uncompressed images and Rice-compressed FITS: smaller and much faster.

Free to use until 31 December 2026. Unpacking stays free without a time limit.

What's new:

• WAV audio has its own predictor. 16-bit PCM WAV files no longer go through the general model: each sample
  is predicted from the previous ones and from the other channel. On a 10 MB piano recording (Bach, March in D,
  from Wikimedia Commons) the result went from 4,739,410 to 2,897,201 bytes (47.6% → 29.1% of the original),
  packing from 46 s to 2.4 s, unpacking from 16 s to 0.8 s. On the 70 sounds that ship with Windows: 32.3% → 22.8%.
• Uncompressed images use the fast image coder that raw camera FITS frames already used: BMP, uncompressed
  TIFF, PGM/PPM and DICOM medical images. The Silesia MR scan: 2,025,436 → 1,879,794 bytes, packing from 2 min 32 s
  to under 2 s. The Mandrill TIFF: 3.7% smaller, in 0.3 s instead of 16 s. Clean photos and screenshots stay with
  the general model, which does better on them.
• Rice-compressed FITS images (fpack, as served by the SDO archive) now reach the fast image coder after
  unpacking. An SDO/AIA image: 4.9% smaller, packing from 95 s to 1.4 s, unpacking from 17 s to 0.3 s.
• Repeated material stays with the general model: a sound or image that appears twice in an archive, a tiled
  image or a synthetic test tone is packed exactly as before, because the general model can copy it.
• About window with the version and the third-party notices (CFITSIO, minimp3).

On our 27 public test files: 49.5% → 46.5% of the original, packing 21 min 34 s → 19 min 43 s, every file back
byte for byte. Of our 393 test files (2.9 GB) the new steps touch only the five files above, and all five got
smaller. These five, 110 further audio and image test cases and the 27 public files all come back byte for byte;
on 15 other files we checked that the output is byte for byte the same as with beta 4.

Compatibility: beta 5 opens every file made with beta 1 to 4. Files with WAV audio or uncompressed images made
with beta 5 need beta 5 or later; earlier betas refuse them with an error instead of guessing.

Updating: download cmz-1.0-beta5.exe and start it. If an earlier beta is installed, cmz offers to update itself.

SHA-256 of cmz-1.0-beta5.exe:
b3f04c642a53d743b2d0b3caa635ed5c057e72a5f29fc124a9f0f839f4565f62

Requirements: 64-bit Windows 10 or 11. Beta terms: see the README.

Feedback, especially files where cmz does worse than you expected: fmolnar.no1@gmail.com

cmz 1.0 beta 4

cmz 1.0 beta 4 — much faster and smaller on documents full of screenshots.

Free to use until 31 December 2026. Unpacking stays free without a time limit.

What's new:

• Long repeats are recognised across the whole file. Manuals and reports often repeat the same toolbar, dialog
  or logo in dozens of screenshots. cmz now spots such stretches anywhere in the file and stores them as a short
  reference instead of predicting them bit by bit. On a 3.7 MB PDF manual exported from Word, with 184 screenshots,
  the result went from 588,544 to 429,671 bytes (16.0% → 11.7% of the original), packing from 8 min 15 s to
  1 min 14 s, and unpacking from 6 min 48 s to 39 s.
• Other files gain where they repeat themselves: a .tar.gz of source code 2.6% smaller and twice as fast
  (packing 4 min 30 s → 2 min 14 s, unpacking 3 min 16 s → 1 min 15 s), a Word .docx 1.5% smaller (packing
  68 s → 41 s), a log file 4.7% smaller. The Silesia corpus: 37,273,956 → 37,229,114 bytes.
• On small files where the new step applies, cmz tries both ways and keeps the smaller result, so packing can
  take a few seconds longer there. No file gets larger than with beta 3.

Checked on 367 test files (2.8 GB): every file comes back byte for byte; 9 got smaller, none got larger, and
the other 358 are packed exactly as with beta 3.

Compatibility: beta 4 opens every file made with beta 1, 2 and 3. Files made with beta 4 may need beta 4 or
later; in that case earlier betas refuse them with an error instead of guessing.

Updating: download cmz-1.0-beta4.exe and start it. If an earlier beta is installed, cmz offers to update itself.

SHA-256 of cmz-1.0-beta4.exe:
dc6576caccee492476a31a6451289904c8718cfbe6b60c1809d035eae4b342aa

Requirements: 64-bit Windows 10 or 11. Beta terms: see the README.

Feedback, especially files where cmz does worse than you expected: fmolnar.no1@gmail.com

cmz 1.0 beta 3

cmz 1.0 beta 3 — smaller files on almost everything, and a fix for multi-file sessions.

Free to use until 31 December 2026. Unpacking stays free without a time limit.

What's new:

• Smaller files. We looked at how well cmz predicts every single bit, and found a rounding flaw in the last
  stage of its predictor: it stayed too cautious exactly where it was most often right. Fixing it, and adding a
  small calibration step that notices when predictions start to go wrong, made 365 of our 367 test files smaller:
  Word and Excel files 0.6–1.4%, plain text 0.2%, the Silesia corpus 37,387,248 → 37,273,956 bytes, enwik8
  20,486,868 → 20,439,134 bytes. Compression and unpacking take about 3% longer.
• Fixed: one file in a session could come out much larger. When several similar files were compressed in one
  go, cmz reused the structure it had found in the earlier files. For a spreadsheet whose body looked different
  from its beginning this went wrong: 216 KB became 283 KB. Now every file's structure is decided by its own
  analysis, so compressing files together no longer makes any of them larger.
• Includes everything from beta 2: the progress display, and skipping already-packed data in a moment.

Checked on 367 test files (2.8 GB): every file comes back byte for byte; 365 got smaller, one 0.7 MB astronomy
image grew by 132 bytes, one RAR archive is unchanged.

Compatibility: beta 3 opens every file made with beta 1 and beta 2. Files made with beta 3 need beta 3 or later;
the earlier betas refuse them with an error instead of guessing.

Updating: download cmz-1.0-beta3.exe and start it. If an earlier beta is installed, cmz offers to update itself.

SHA-256 of cmz-1.0-beta3.exe:
783e760cf65d2969399d58da23944a6d9a302931112bebed47ba3afd31b7546b

Requirements: 64-bit Windows 10 or 11. Beta terms: see the README.

Feedback, especially files where cmz does worse than you expected: fmolnar.no1@gmail.com

cmz 1.0 beta 2

cmz 1.0 beta 2 — progress display and faster handling of already-packed data.

Free to use until 31 December 2026. Unpacking stays free without a time limit.

What's new:

• You can see what cmz is doing. The status column and the bar show each step: preparing, analysing,
  compressing with a percentage, decompressing with a percentage, rebuilding. While cmz is still analysing a file
  (it cannot know yet how long that takes) the bar shows a moving light instead of standing still.
• Already-packed data is skipped in a moment. cmz now recognises data that nothing can shrink further (RAR
  archives, the payload of most installers, encrypted data) and stores it as it is; only the rest goes through the
  compressor. A 2.2 MB RAR archive: 58 s → 0.2 s. A 40 MB EXE installer: 161 s → 10 s, and it unpacks in 1 s.
• Faster on some large astronomy cubes. When one of two methods has clearly won, cmz stops the other one
  early (an 85 MB radio data cube: 239 s → 141 s, same size).
• Clearer error messages: a damaged, incomplete or too-new .cmz file is reported in plain English.

Checked on 367 test files (2.8 GB): every file comes back byte for byte, and no file got bigger.

Compatibility: beta 2 opens every file made with beta 1. A file that beta 2 made with skipped (stored) parts needs
beta 2 or later; beta 1 refuses it with an error instead of guessing. If you share .cmz files, ask the others to
update too.

Updating: download cmz-1.0-beta2.exe and start it. If beta 1 is installed, cmz offers to update itself.

SHA-256 of cmz-1.0-beta2.exe:
3ddda01a67d352aad6471677c952c66e319b284a3c0b827cb48375b784d7b317

Requirements: 64-bit Windows 10 or 11. Beta terms: see the README.

Feedback, especially files where cmz does worse than you expected: fmolnar.no1@gmail.com

cmz 1.0 beta

cmz 1.0 beta — the first public beta.

Free to use until 31 December 2026. Unpacking stays free without a time limit, and every later version of cmz opens the files made with this beta.

What it does: lossless compression for Windows that also shrinks already compressed files. JPEG photos about 24% smaller, MP3s about 13%, Office files often to less than half, astronomy FITS data 17% tighter than 7-Zip. Every file comes back byte for byte. Measurements: https://ferencmolnar01.github.io/cmz/

Getting started:

Download cmz-1.0-beta.exe below. It is not code-signed during the beta, so Windows SmartScreen may warn: choose “More info”, then “Run anyway”.
On first start cmz offers to install itself for your user account (no administrator rights needed): Start menu, Explorer right-click “Compress with cmz”, and double-click to open .cmz files.
SHA-256 of cmz-1.0-beta.exe: 5e263ef29ce5b2ff5fa430ea339bc40fbb8aed0f0c928d7873bc4880dc1c5d07

Requirements: 64-bit Windows 10 or 11. Beta terms: see the README.

Feedback, especially files where cmz does worse than you expected: fmolnar.no1@gmail.com

http://localhost:8765/proba_oldal.html