CTW File

What are CTW files and how to open them

Are you having problems opening a CTW file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CTW files.

What is a CTW file?

CTW files have multiple uses, and Casio Disc Title Printer Label is one of them. Read more about the other uses further down the page.

Casio Disc Title Printer Label

Casio Disc Title Printer Label files store label-design data created in Casio's "DISC TITLE PRINTER" application. These files capture text, layout, template, image placeholders, and print pattern settings, used for printing titles, artist names, track lists, folder or file names, or images onto discs with Casio's Disc Title Printer devices.

Such files are written by the DISC TITLE PRINTER software when a user composes or edits a label design, then chooses Save (or Save As). Later the same software reads them either to continue editing the design or to send the layout to the printer. Versions of the software (including for the CW-100 model, version 4.10) support importing old label data files, including ones with this file format, converting them to the current version's internal layout.

Files begin with the ASCII literal "CD-RTITLEPRINTER" at offset 0, and somewhere near byte 362 contain the string "Ver." indicating version metadata.

How to open CTW files

Important: Different programs may use files with the CTW file extension for different purposes, so unless you are sure which format your CTW file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested five different CTW openers which you will find listed below.

Last updated: September 19, 2026

All known file formats using extension .CTW

While Casio Disc Title Printer Label is a popular type of CTW-file, we know of 2 different uses of the .CTW file extension. Different software may use files with the same extension for different types of data.

Context Tree Weighing (CTW) Compressed File

Context Tree Weighing Compressed File stores data that has been compressed using the Context-Tree Weighting (CTW) algorithm, a lossless compression method developed at the Eindhoven University of Technology. It is designed to encode binary sequences using a statistical model that mixes probabilities from all possible prediction suffix trees of bounded depth, which makes it especially effective for compressing data with structure or redundancy such as text. The program provided by TU-e both encodes raw input data into this CTW compressed form and decodes such files back into the original, uncompressed form.

The encoder builds a context tree up to a fixed depth, where each node tracks count statistics for the number of zeros and ones observed following the context represented by that node. For each new input bit, the compressor updates the counts along the path defined by recent bits, and prediction probabilities are formed by combining child node predictions with the local count estimate, often using estimators such as the Krichevski-Trofinov (KT) estimator. An arithmetic coder uses these probabilities to emit compressed output. When decoding, the same tree construction and arithmetic coding process is reversed to reproduce the original data.

Each file begins with a fixed signature allowing identification of this format: the bytes 0x00 0x0C 0x00 0x00 appear at offset 0, and the bytes 0x06 0x20 0xB6 0xAD appear at offset 8.

Various apps that use files with this extension

These apps are known to open certain types of CTW files. Remember, different programs may use CTW files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about CTW file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.