What is ZIPX file type, WinZip archive format

ZIPX extension

ZIPX file extension designates, by definition, a ZIP file employing a compression method different than Deflate or Deflate64.
The extension was introduced by WinZip team, starting from WinZip 12.1 (released as trialware program on 13 September 2008), in order to differentiate files created with new compression algorithms from ZIP files compressed with classic Deflate algorithm - as legacy applications would be not able to read new files.

Like for ZIP files, WinZip provides its custom file spanning scheme for splitting ZIPX archives (Z01 extension).

PeaZip can create, open and extract ZIPX files with Bzip2, LZMA, LZMA2 / XZ, and PPMd (technically ZIPX files by definition); custom WavPack, MP3 and JPEG pre-compression filters are currently unsupported (both for reading and for writing).
To add support to WavPack in PeaZip, you can use WavPack7z plugin (free of charge, closed source, hence cannot be provided with PeaZip packages), simply extracting the 32 or 64 bit plugin in PeaZip's folder, in (peazip)/res/7z/Codecs path.

ZIPX file format specs

WinZip's ZIPX standard is based on PKZip's ZIP format specifications, with only difference of employing newer data compression algorithms - BZip2, LZMA / LZMA2 (XZ), PPMd and others (superseding classic Deflate / Deflate64 algorithm) - and employing custom pre-compression filters (WavPack, MP3 and JPEG filter) to improve compression of images and other media data structures.
This results in zipx providing higher, improved compression ratio compared to classic zip/Deflate, at cost of higher computational cost, comparable with compression ratio of formats like RAR, ACE, and in some cases 7-Zip's 7Z / XZ file format - modern archiving formats also relying in LZMA and PPMd -family compression algorithms and multimedia precompressors.

ZIP or ZIPX file extension
The possibility of employing alternate compression methods is anyway already featured in standard ZIP format definition, so using an alternate designation as ZIPX is merely a choice and does not (technically) define a different, independent standard.
The file extension modification from zip to zipx was intended to avoid ambiguity with users (openly marking it as new type, with new extension) and prevent older archivers to try to handle the new zipx standard as it was a classic zip file, failing to support its newer features.

ZIPX format compression performances

On file compression benchmark, and maximum compression benchmark pages you can compare how .zpix format fares, in terms of compression ration and compression / extraction computation speed, with mainstream formats such as .7z, .rar, and .zip, testing various software implementations (PeaZip, WinRar, WinZip).

ZIPX format encryption features

ZIPX files supports new AES-based WinZip's AE encryption (128 bit and 256 bit), which is also part of ZIP standard - and optionally, for legacy support only, old ZipCrypto (Zip 2.0) cryptography.

ZIPX file format limitations

As in current Zip format revision, Zipx format is limited to maximum 4 billion files per archive (2^32) and to 16 EB as max file size (2^64), either for the single input files and for the total size of the archive - as ZIP64 standard zip archives - likely exceeding user's needs and limits of current filesystems implementation.
Read more about size and number of items limitations of various archive types.

External online resources about .zipx archives: ZIPX Wikipedia page, WinZip Knowledge Base entry for ZIPX standard.

Synopsis: .ZIPX file extension. What is WinZip archive type. What are ZIPX file format specifications and features in terms of compression speed, compression ratio, advanced options, and encryption.

Topics: zipx file extension specs, zip format vs zipx format

PeaZip > FAQ > ZIPX file extension