Can network tuners make a virtual HTPC possible?

Can network tuners make a virtual HTPC possible?

Any regular reader of Garry Whittaker’s blog here on TDL will have seen his posts on DVBLogic’s DVBLink TVSource V2 which allows any tuner (DVB-T or DVB-S) installed in a computer to be used by another computer (client) on the network.  If you follow me on Twitter or have read my post here on TDL (I’m A Windows Media Center PC…) you will know that I have the view that Windows Media Center should be integrated into Windows Home Server (WHS).  Now as soon as I read Garry’s post the first thought I had was “I can put my tuners into my WHS and create a tuner pool for other computers to use” followed closely behind by a second thought “I could run our HTPC as a virtual machine on the ‘always on’ WHS and reduce our energy useage”.

A slight digression; I have also been feeling quite dissolusioned with the “extender model” (the HTPC is locked away and not used directly) since Microsoft (and it’s hardware partners) seem to be moving away from using extenders to get Windows Media Center into the living room.  As you might well know there are features of Windows Media Center that do not work on extenders:

  • Full DVD rips (with menu’s, subtitles, etc)
  • Flash streaming used by catch-up TV services (TunerFreeMCE for example)
  • The new SkyPlayer*

* Although SkyPlayer is available on Xbox360 for non-subscribers like myself the Pay-Per-View content is non-existent on Xbox compared to Media Center.

There are people moving away from extenders and instead using the HTPC directly connected to their TV.  That isn’t easily accomplished in our house because 1) the HTPC was built on a budget and so isn’t as quiet as it could be and 2) since changing to extenders we have moved our TV to another location on an internal wall where there are no TV signal outlets.

Now to bring this back on track, the announcement of DVBLink TVSource V2 means people can have a HTPC directly attached to the TV without the need to have tuners or indeed a TV signal outlet anywhere near.  It also means that portable machines (netbooks, laptops, nettops, etc) can also enjoy the benefits of live TV using the DVBLink TVSource Client.  The most exciting prospect for me was being able to centralise the tuners into a pool on the WHS.  I should explain that I have two Hauppauge Nova-T-500 which are hybrid DVB-T dual tuners and one is installed in the HTPC and the other is in the desktop PC.  Ideally I’d have both cards in the HTPC but the desktop PC is used for watching live TV often enough that this wasn’t feasible.

The first step was to get DVBLink TVSource V2 up and running on the desktop PC with the DVBLink TVSource Client installed on my netbook (ASUS EeePC 1000 running Windows 7 Home Premium).  I followed the instructions provided in the post on DVBLogic’s forums and after hitting a few dead ends I had live TV running simultaneously on the desktop PC and netbook.  I should say that the dead ends were my fault for missing out some of the more unobvious steps but DVBLogic were amazing and provided support to me via Twitter.

Next thing was to do some research about installing a Nova-T-500 card under Windows Server 2003 (the operating system that WHS is built on) and was relieved to discover that the card can be installed.  I moved the tuner card from the desktop to the WHS and restarted it.  The tuner card needed to be installed manually so I pointed it to the latest drivers I had downloaded and then went through the steps required to install and configure DVBLink TVSource V2.  After removing the software from the desktop and installing the client I had two live streams running and recording.  The CPU useage on the WHS was about 10-15% with around 1-2% network useage of a 1Gbit port.

Now to the burning question and the real topic of this post.  Could a virtual HTPC running on the WHS perform the same tasks as the physical HTPC we are currently using?  The only barrier is the fact that some hardware isn’t available inside a running virtual machine and this is most certainly the case with Microsoft’s Virtual PC and Virtual Server products.  Now that we have network tuners that barrier has been removed.  I set about installing a Windows 7 VM onto the WHS (CPU: Intel Celeron D 352 3.2GHz / RAM: 2GB) and after completing the installation of Virtual Machine Additions and the DVBLink TVSource Client.  The end result was the virtual DVBLink Tuners and a set of channels within the guide:

Editing source information for BBC One

  

The Guide populated with all the channels fed from DVBLink TV Source

[Note: The text below is copied from my own post I made on the DVBLogic forums here]

The next step was to re-configure our Xbox360 Extender to use the new virtual machine which was almost incident free. I had to increase the RAM allocated to the VM to 1GB as the initial 512MB simply wasn’t enough and setting up the Extender kept failing. I only have 2GB in our WHS and 512MB of that is already allocated to another VM that runs our DNS and Email server and currently our WHS utilises just 512MB of RAM. After making that configuration change I got the Extender configured and was able to browse around Media Center via the Xbox360. Then the final hurdle, could I watch Live TV via the Extender using the Windows 7 virtual machine as the host? There really should be a drum roll here…

No I couldn’t. Using the Virtual Server Administration it would seem that CPU wasn’t an issue, the VM was using about 50% CPU, although I could be wrong. I suspect the real issue is network traffic (Virtual Server only emulates a 100mbit network card even though the server has a 1Gbit card) given that the network statistics were jumping rapidly. The VM is trying to pull in the DVBLink feed and pump it back out to the Extender and at the same time the physical server is trying to send data to the VM via the virtual network card.

This is a project without budget so I can’t try and resolve this by throwing a better CPU or more RAM at it in the hope I can get it working (I would if I was sure of success). I am going to try running the VM using Windows Virtual PC on another desktop to see if that makes things any better. I suspect that this sort of setup needs an improved VM solution capable of near physical hardware performance. I’d ideally try this using Hyper-V but that would mean converting our WHS into a VM too

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7 thoughts on “Can network tuners make a virtual HTPC possible?

  1. That might be an option. I will try and test that out to see if recording does work. Just copying the VHD over to my desktop to give Virtual PC a try.

  2. Out of interest – and apologies if there’s an obvious reason why not – but have you considered reversing your config?

    In other words, a Windows7 HTPC as the physical box running WHS in Virtual PC? That way, your tuners resolve directly to the HTPC and you bypass the problem of taking a feed into your virtual HTPC from WHS while trying to push to an extender. You should in theory at least halve the network traffic.

  3. @dogged I also suggested that and I believe the concern is recovering WHS if there is a failure

    @Jayc see you tweeted that recording works pretty well which is really good news

  4. @dogged That is a good suggestion and I’ve read about people doing this before. I think that it comes down to individual needs and how much you rely on the HTPC.

    In our household Media Center is everything to us and does all our recording so if it suffers a hardware failure or the OS gets corrupted and needs restoring I need to be able to do this quickly and easily from the WHS.

    The issues with such a setup would be that should I need to restore the HTPC that I’d first have to move the virtual machine somewhere else (assuming I could and the hard drive hasn’t failed completely).

    Now there are ways around that, there are ways to backup and restore the WHS backup database, but for me the risks are too high. That isn’t to say that this wouldn’t work or that it isn’t a solution for some.

    @Garry Yes the recording was fine apart from some break up of picture which I don’t think is related to the signal but possible network related. This certainly wasn’t so bad that I’d turn back from using network tuners. The other real test was could the desktop wake from sleep and record without tuner issues which I’m happy to report it could.

    I’m going to be moving the 2nd Nova-T-500 card from the HTPC into the WHS very soon and see how things work out. I plan on doing another follow up post showing CPU and network stats when recording 1, 2, 3 and 4 streams.

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