SID File Extension

Have a problem opening a .SID file? We collect information about file formats and can explain what SID files are. Additionally we recommend software suitable for opening or converting such files.

What is the .SID file type?

The .sid filename extension is primarily associated with the MrSID Image (.sid) file type/format. Standing for Multi-resolution Seamless Image Database, MrSID is a proprietary bitmap image file format and data compression algorithm, developed by LizardTech with a focus on GIS applications. MrSID uses wavelet-based lossless/lossy compression, providing good ratios with no or minimal artifacts.

The key feature of MrSID is instantaneous handling of large image sets by using tiled file structure and multiple resolutions. Well suited for streaming map data for network access, MrSID is used to store and handle large map images (e.g., aerial). A .sid file is a bitmap MrSID image. Typically, it is a large GIS map or a NASA space photographic image. SID files incorporate geo-reference metadata.

The MrSID image format is natively handled by GeoExpress (LizardTech) and supported by many other commercial GIS systems. Besides LizardTech's free ExpressView browser plugin and GeoExpress CLI converter tools, SID image files can be viewed with several image viewers.

With reference to Commodore 64 (C64), a popular personal-computer device of the 1980's, the .sid extension is conventionally assigned to C64 Sound Interface Device (SID) music/sound files. SID was a simple built-in hardware sound synthesizer device with only three (later, four) channels (voices). A .sid file is a C64 music piece ('chiptune'). On modern hardware, such .sid files can be used with a series of C64 emulators or played back with several media players via plugins. Large SID music collections exist on the Internet.

Another occurrence of the .sid extension has to do with the Symantec pcAnywhere Security Identifier (SID) file type/format. Symantec pcAnywhere is a commercial remote PC administration tool by Symantec that uses .sid files as security ID tokens. A .sid file contains a numerical string, representing a connection ID. To allow connection to a remote host, both local and remote hosts must share the same SID.

Lastly, the .sid extension is also assigned to game backup data files (.sid) created by the 'Backup and Restore Games' feature of the Steam gaming portal. The backup feature allows to create a local backup of any installed Steam game and restore it later. A valid backup should contain a restore executable (.exe), and several .sid, .sim, and .sis data files. Incomplete backups cannot be restored.

Software to open or convert SID files

You can open SID files with the following programs: 

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