64-bit

Important to remember is that 64-bit applications can only use 64-bit codecs/filters, and 32-bit applications can only use 32-bit codecs/filters.

The 64-bit versions of Windows can run both 32-bit and 64-bit applications. Most software is still 32-bit, so you will need a 32-bit codec pack for them. Only a few applications are 64-bit and thus need a 64-bit codec pack.

An example of a 64-bit application is Windows Media Center. Windows Explorer is also a 64-bit application. Both a 32-bit and a 64-bit version of Windows Media Player is included with x64 versions of Windows. The 32-bit version is used by default for compatibility reasons. So if you plan to use WMP you need the 32-bit codec pack!

It is recommended to install both the 32-bit codec pack and the 64-bit codec pack. The order in which you install them does not matter.

For two reasons:

1. Users are expected to install both the 32-bit and the 64-bit versions of the pack. To save space, applications like MPC-HC and MediaInfo are only included in the 32-bit pack.
2. It is recommended to use the 32-bit version of MPC-HC. It has better compatibility because some codecs and filters are only available for 32-bit. For example madVR. It has better stability. Some problems and bugs only exist with the 64-bit version. It has the same performance, which means that the 64-bit version does not really have any advantages.