WMC was included with Windows 7 but is an additional $100 for Windows 8/8.1 and an additional $10 for Windows 8/8.1 Pro. For detailed discussion of WMC, please see website.
There is also another 3rd party software called My Channel Logos that adds channel logos to the WMC channel guide. By default WMC has a 4 tuner limit for each type (ATSC, CableCard) of tuner, but a 3rd party software product called TunerSalad increases the number of tuners to 32 per type you can use up to 32 cable tuners (11 Primes = 33 cable tuners) and 32 ATSC tuners, for a total of 64 tuners.
When running WMC, an additional, separate ATSC tuner can be used with the PC and WMC will combine both the Prime and ATSC tuner in the guide for live TV and recording. Many other software options are available please see the list in this Wiki and the Silicondust website for details.
The HDHomeRun can also be controlled via a command-line application which is available for Windows, Mac OS X, Linux, FreeBSD, and other POSIX-compliant operating systems.
The HDHomeRun Windows driver presents the tuners as standard BDA tuners, enabling BDA-compliant applications to work with the HDHomeRun. HDHomeRun normally receives an IP address via DHCP but will also work via an auto IP address if no DHCP server is available.
This allows it to stream content to multiple viewing locations. Instead it receives a live TV signal and then streams the decoded video over a local area network to an existing smart phone, tablet computer, smart tv, set top streaming device, computer, or game console. Unlike standard set-top box (or set-top unit) appliances, HDHomeRun does not have a video output that connects directly to the user's television.