.PAC File Extension

There are 4 file types use the .PAC file extension:

  1. PAC Subtitles File
  2. Proxy Auto-Config File
  3. SBStudio II Song File
  4. STAD Graphic File

1. PAC Subtitles File

PAC Subtitles File
  • Developer Screen Subtitling Systems
  • Popularity
    4.2 (24 votes)
  • Category Video Files
  • Format N/A

Proprietary subtitles format created by Screen Subtitling Systems; used for synchronizing closed captions with a video timeline; can be edited with subtitle editing software such as EZTitles and converted to more standard formats, including .SRT and .SUB.

Software's name License Platforms
BroadStream Solutions Poliscript Create BroadStream Solutions Poliscript Create Paid Windows
BroadStream Solutions Wincaps Q4 BroadStream Solutions Wincaps Q4 Free Trial Windows
EZTitles EZTitles Free Trial Windows
Subtitle Edit Subtitle Edit Free Windows

Updated: October 8, 2017

2. Proxy Auto-Config File

Proxy Auto-Config File
  • Developer Netscape
  • Popularity
    4.1 (60 votes)
  • Category Web Files
  • Format Text

A PAC file is a configuration file used by web browsers to select an appropriate proxy server. It contains one or more JavaScript functions with one of them named FindProxyForURL, which defines rules for choosing a proxy server based on a given URL. PAC files are used for controlling and load-balancing Internet traffic, especially in corporate environments.

PAC files are enabled in web browsers by entering the PAC file URL in the proxy connection settings, or by using the Web Proxy Auto-Discovery (WPAD) protocol. When executed, a PAC file returns a string with one or more proxy server URLs. PAC files are typically hosted on a web server and are named proxy.pac.

Since PAC files contain the configuration in plain text. You can use a text editor, such as Microsoft Notepad or Apple TextEdit to view or modify the files.

NOTE: The PAC file format was originally released in 1996 for use by Netscape Navigator 2.0.

Software's name License Platforms
Apple Safari Apple Safari Bundled iOSMacWindows
Microsoft Internet Explorer Microsoft Internet Explorer Freeware MacWindows
Mozilla Firefox Mozilla Firefox Open Source AndroidChrome OSiOSLinuxMacWebWindows

Updated: May 11, 2019

3. SBStudio II Song File

SBStudio II Song File

Song format, called a PAC or package file, used by SBStudio; made up of data blocks that store song information and audio data.

Software's name License Platforms
FMJ-Software Awave Studio FMJ-Software Awave Studio Shareware Windows
SBStudio II SBStudio II Windows

Updated: September 21, 2009

4. STAD Graphic File

STAD Graphic File

Image format used by the STAD program for Atari ST systems; saved as a black and white image with a resolution of 640x400 pixels; considered a high-resolution graphic for Atari computers.

Software's name License Platforms
Lemkesoft GraphicConverter Lemkesoft GraphicConverter Shareware Mac
XnViewMP XnViewMP Freeware LinuxMacWindows

Updated: September 3, 2009

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