Using AC3Filter in Media Center
by Michael Healy @ 6:00 am on February 24th, 2009 in codecs, windows 7 with 30 Comments
One of the main problems encountered by those who use SPDIF output on their Media Center is the inability to control volume through the PC. The most common solution is to control the volume through the receiver but this means using a different remote (or worse getting up to turn the knob!). A solution to this problem is to use AC3Filter to control the gain of the SPDIF output. This will allow you to artificially change the volume of the digital output through Windows.
The first step to using AC3Filter to control SPDIF volume is to download and install the latest version of AC3Filter from ac3filter.net. Unfortunately, AC3Filter doesn’t currently support x64 operating systems and only comes in an x86 package. Next we need to follow the same steps as for installing FFDShow to work with Media Center and Media Player.
You will need to have the “Take Ownership” registry hack we’ve used before in changing our Media Center theme. You can download the registry file to enable this menu here. Once you have the .reg file downloaded double-click to install the registry fix and permit it to change the registry when prompted.
To enable AC3Filter in Media Center/Player for music, open Windows Explorer and navigate to “C:\Windows\system32\” and locate the file name “MP3DMOD.DLL”. Right-click to bring up the menu and choose “Take Ownership” then rename the file “MP3DMOD.DLL.bak”. This will disable the native filter and can be reversed by changing the file name back at any time.
To enable AC3Filter for live television and other formats using the MPEG2 codec inside of Media Center there is also a registry entry that needs to be changed. First we need to find the CLSID for AC3Filter. To do that download Radlight’s Filter Manager right here. Extract the files to any location and run the exe file inside. Inside this program expand DirectShow Filters and scroll down to AC3FIlter. Right click the entry and select “Copy CLSID to Clipboard”.
Next, open regedit in Administrator mode: using the start menu type regedit then press ctrl-shift-enter. Then navigate to “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\ CurrentVersion\MediaCenter\Decoder”. Inside there should be two strings, right-click “PreferredMPEG2AudioDecoderCLSID” and choose “Modify..”. Then enter the CLSID that you’ve copied from FilterManager in the box and press ok
Media Center will need to be restarted before the changes will take effect but that should set your music, live television and most anything in Media Center to use AC3Filter instead of the native codecs included in Windows 7. The stability of this hack has not been tested outside of systems using purely Media Center as the user interface and may carry unintended consequences, perform at your own risk.
If you have any trouble (or success!) getting this hack to work be sure to post a comment below!
