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ATSC A/52 and AC-3 Decoder

A fork/clone of the subversion repository at for the a52codec included as part of the Perian releases. Although Perian has been retired, the source code and downloads continue to be available.

The trunk branch represents the latest code from the subversion repository. The master branch represents the version that was released with Perian 1.2.3 plus some Xcode project updates and a fix for an incorrect header (description here) generated while performing AC-3 pass through. The various perian-* tags indicate which version of the a52codec source was included with each Perian release.

If you are not using AC-3 pass through (see here) then there’s nothing for you to see here so move along and install the standard Perian 1.2.3 release.



  1. Install Perian using the Perian 1.2.3 Installer
  2. If you really need the AC-3 pass through fix either build the A52Codec.component yourself from the master branch sources or retrieve a pre-built copy from the a52codec project’s downloads area
  3. Replace the /Library/Audio/Plug-Ins/Components/A52Codec.component from the Perian installation with the one you just built or downloaded


You can download this project’s source code in either zip or tar formats.

You can also clone the project with Git by running:

$ git clone git://

Pre-built universal binaries of the A52Codec.component software runnable on Mac OS X 10.4 or later which include the AC-3 pass through fix are available from the a52codec project’s downloads area.


Visit the GitHub project page (source code etc.) at