SUB File

What are SUB files and how to open them

Are you having problems opening a SUB 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 SUB files.

What is a SUB file?

SUB files have multiple uses, and DVD Subtitles is one of them. Read more about the other uses further down the page.

DVD Subtitles

Files that use the .sub file extension are usually files that store movie subtitles. These files contain data about the movie subtitles, such as the subtitle text, the point at which each subtitle should be displayed, and information about the corresponding video file.

It is important to note that the SUB file does not contain any actual video data. Just the references for the subtitle information.

There are several different subtitle authoring and ripping applications that use the SUB file extension on supported files, although the formats may not be compatible. Try out a few different apps to see which one can open yours.

How to open SUB files

We have identified six SUB openers that are compatible with this specific type of SUB file.

Programs that open DVD Subtitles files

Last updated: August 13, 2026

All known file formats using extension .SUB

While DVD Subtitles is a popular type of SUB-file, we know of 4 different uses of the .SUB file extension. Different software may use files with the same extension for different types of data.

CloneCD CD Image Subchannel Data

CloneCD CD Image Subchannel Data (.sub) is a companion file used by the disc copying tool CloneCD when making a full, bit-perfect backup of a CD. The main purpose is to store the disc's subchannel data - low-level bits not included in standard image formats - which can contain critical metadata such as copy protection, CD-Text, ISRC codes, and timing/location information that some discs rely on to function exactly as the original.

CloneCD creator programs write the .sub file alongside two sibling files: an .img file holding the main user and audio data of every sector, and a .ccd control descriptor that describes track layout, indexes, and lead-in/lead-out data. Without the .sub file, many disc protections or special features stored in subchannels will be lost.

The .sub file stores 96 bytes of raw subchannel data per sector, corresponding to the P through W subchannel channels for every sector in the image. This includes 12 bytes each for P and Q (which contain track start flags, timecodes, control/ADR flags, CRC), and 12 bytes each for channels R-W (often unused but used for extensions like CD-Text or CD+G) The subchannel data is de-interleaved so that each channel's bytes are stored sequentially rather than interleaved per frame. Optional: the .sub file may be omitted if the disc has only standard subchannel data (Red Book-audio/data) and no additional protections or metadata requiring full subchannels.

File identity is confirmed by its byte-signature beginning at offset zero as shown in CloneCD's TRiD signature: FFFF… 41 01 01 00 … marking the start of subchannel data records.

SUB opener for Windows

We have identified one SUB opener that is compatible with this specific type of SUB file.

Flipper SubGhz Data File

We know that one SUB format is Flipper SubGhz Data File. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

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

Philips SVCD Designer Subtitles

We know that one SUB format is Philips SVCD Designer Subtitles. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of SUB files. Remember, different programs may use SUB 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 SUB file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.