ASS File Extension

What is ASS file?

File with .ASS extension contains a script for creating video subtitle text formatted using SubStation Alpha standard. ASS files are generated by Aegisub, an open-source multiplatform tool for creating and editing video subtitles. ASS is a text file divided into four or five parts, which contain:

• Information about the script – version, author, title, and general information related to screen format and resolution generated by Aegisub,
• V4 Styles – information about text formatting and styles, including:
  • Fonts,
  • Fonts size,
  • Colors,
  • Positioning,
  • Text alignment,
• Events – list of events and text timings in the format G:MM:SS.sse, along with additional attributes,
• Pictures – UUE-encoded images (optional),
• Fonts – fonts data.

ASS format is an extension of SubStation Alpha standard that closely follows SSA v4+ specification. Files conforming to basic SSA v4 standard use .SSA extension. ASS subtitle scripts are used to overlay subtitles on video image in a process called hardsubbing. Matroska multimedia containers (MKV files) also support ASS subtitles, which can be added to the video as a separate file (so called softsubbing).

Programs which support ASS file extension

The following list contains programs grouped by 3 operating systems that support ASS files. ASS files can be encountered on all system platforms, including mobile, yet there is no guarantee each will properly support such files.

Updated: 12/08/2023

How to open file with ASS extension?

Being unable to open files with ASS extension can be have various origins. What is important, all common issues related to files with ASS extension can be resolved by the users themselves. The process is quick and doesn’t involve an IT expert. The following is a list of guidelines that will help you identify and solve file-related problems.

Step 1. Install Aegisub software

The main and most frequent cause precluding users form opening ASS files is that no program that can handle ASS files is installed on user’s system. This issue can be addressed by downloading and installing Aegisub or different compatible program, such as VLC media player, MPlayer, URUworks Subtitle Workshop. The full list of programs grouped by operating systems can be found above. If you want to download Aegisub installer in the most secured manner, we suggest you visit website and download from their official repositories.

Step 2. Check the version of Aegisub and update if needed

You still cannot access ASS files although Aegisub is installed on your system? Make sure that the software is up to date. It may also happen that software creators by updating their applications add compatibility with other, newer file formats. This can be one of the causes why ASS files are not compatible with Aegisub. The latest version of Aegisub should support all file formats that where compatible with older versions of the software.

Step 3. Assign Aegisub to ASS files

If you have the latest version of Aegisub installed and the problem persists, select it as the default program to be used to manage ASS on your device. The process of associating file formats with default application may differ in details depending on platform, but the basic procedure is very similar.

Change the default application in Windows

• Right-click the ASS file and choose Open with option
• Next, select the Choose another app option and then using More apps open the list of available applications
• Finally select Look for another app on this PC, point to the folder where Aegisub is installed, check the Always use this app to open ASS files box and conform your selection by clicking OK button

Change the default application in Mac OS

• By clicking right mouse button on the selected ASS file open the file menu and choose Information
• Open the Open with section by clicking its name
• Select Aegisub and click Change for all...
• A message window should appear informing that This change will be applied to all files with ASS extension. By clicking Continue you confirm your selection.

Step 4. Verify that the ASS is not faulty

Should the problem still occur after following steps 1-3, check if the ASS file is valid. Problems with opening the file may arise due to various reasons.

1. Check the ASS file for viruses or malware

Should it happed that the ASS is infected with a virus, this may be that cause that prevents you from accessing it. It is advised to scan the system for viruses and malware as soon as possible or use an online antivirus scanner. ASS file is infected with malware? Follow the steps suggested by your antivirus software.

2. Ensure the file with ASS extension is complete and error-free

If you obtained the problematic ASS file from a third party, ask them to supply you with another copy. During the copy process of the file errors may occurred rendering the file incomplete or corrupted. This could be the source of encountered problems with the file. When downloading the file with ASS extension from the internet an error may occurred resulting in incomplete file. Try downloading the file again.

3. Ensure that you have appropriate access rights

Sometimes in order to access files user need to have administrative privileges. Log in using an administrative account and see If this solves the problem.

4. Verify that your device fulfills the requirements to be able to open Aegisub

If the systems has insufficient resources to open ASS files, try closing all currently running applications and try again.

5. Verify that your operating system and drivers are up to date

Regularly updated system, drivers, and programs keep your computer secure. This may also prevent problems with Aegisub Advanced Substation Alpha Format files. Outdated drivers or software may have caused the inability to use a peripheral device needed to handle ASS files.

Do you want to help?

If you have additional information about the ASS file, we will be grateful if you share it with our users. To do this, use the form here and send us your information on ASS file.