K-Lite Mega Codec Pack 10.5.0
Very good pack. Supplies all the extra codecs needed for encoding and decoding a huge range of formats and file associations can be configured for all your Media Players. Media Player Home Cinema and LAV provide excellent quality.
I recommend custom installing using the Extras + Media Player Home Cinema setting and disabling all the Tray Icons for LAV, ffdshow, etc and Codec News during install. You can leave the other settings how they are except toolbar/adware and the end of install setup.
DON'T FORGET to deselect the TOOLBAR and other ADWARE at the end of the installation setup, accomplished by selecting the "No Thanks" check-mark to avoid the installation of adware! The separate update packs, or "quick update" option for new versions then won't install the adware junk if you remember to select the "No Thanks" option for the junkware/toolbar at the end of the install setup the first time you install K-lite Codec Pack.
If you also use Winamp as a seperate music player (I'm using Winamp 5.65x86 currently), download the Winamp plugin MatrixMixer_0_9_163d from SourceForge, open the extracted folder and copy "out_mixer.dll" into Winamp's plugin folder (C:\Program Files (x86)\Winamp\Plugins) for surround sound on analogue or digital speaker setups. You can configure MatrixMixer from Winamp's Preferences>Plug-ins>Output settings. You can configure Output up to 5.1 or Dolby/Pro Logic II, PCM to 24bit (even 32bit for studio gear, stick to 24bit though), and up to 192kHz audio. Plus there is SPDIF and passthrough settings if you need them, though most decoders will not need you to adjust the SPDIF settings.
MatrixMixer is especially helpful for owners of Creative Zx/ZxR sound cards to replace the missing Stereo Surround feature which is no longer found in the Sound Blaster Control Panel.
Set MatrixMixer Output format to 5.1, (PCM 24bit and 192kHz if you like also), then on the Mixer tab you can set Bass redirection (80Hz for Cutoff frequency, 110Hz or whatever you like).
Only problem with MatrixMixer is you have to set the settings again each time you start up Winamp, but it gives you back stereo surround if you have a Creative Zx/ZxR. I set my Logitec Decoder to 4.1 for stereo surround, but I must leave MatrixMixer still set to 5.1 or it will crash if I set it to 4.1. This provides excellent quality stereo surround with bass redirection.