HTPC Decoding and Rendering Benchmarks: madVR

In the preceding section, we looked at EVR and EVR-CP. Videophiles often prefer madVR as their renderer because of the choice of scaling algorithms available as well as myriad other features. In our original Ivy Bridge HTPC review, I had been very satisfied with HD 4000 and madVR except for a few corner cases involving high frame rate material which also required both luma and chroma scaling (such as 720p60 material). One of the issues in our initial testbed was that we were using DDR3-1333 DRAM. Our current system under consideration uses DDR3-1600. This is more than enough to get madVR working with default scaling algorithm settings for all video material 1080p60 or lesser. Readers interested in seeing madVR in action on the HD 4000 should definitely check out Andrew's excellent piece in Missing Remote comparing HD 2500 and HD 4000 for madVR.

It is not possible to use native DXVA2 decoding with madVR because the decoded frames are not made available to an external renderer directly. To work around this issue, LAV Video Decoder offers three options. The first option involves using software decoding.

LAV Video Decoder (Software Fallback) + madVR
Stream GPU Usage % Power Consumption
     
480i60 MPEG-2 70.84 48.19
576i50 H.264 72.8 50.41
720p60 H.264 75.88 58.23
1080i60 H.264 61.51 59.05
1080i60 MPEG-2 61.22 55.09
1080i60 VC-1 62.22 59.85
1080p60 H.264 73.65 60.91

The second option is to use either QuickSync or DXVA2 Copy-Back. In either case, the decoded frames are brought back to the system memory for madVR to take over. The power consumption profile improves quite a bit, particularly for the 720p60 and 1080p60 streams.

LAV Video Decoder (QuickSync) + madVR
Stream GPU Usage % Power Consumption
     
480i60 MPEG-2 71.37 47.72
576i50 H.264 71.28 49.83
720p60 H.264 75.76 54.92
1080i60 H.264 62.5 56.15
1080i60 MPEG-2 62.02 55.81
1080i60 VC-1 61.86 55.94
1080p60 H.264 66.31 56.58

One of the interesting features to be integrated into the recent madVR releases is the option to perform DXVA scaling. This is particularly interesting for HTPCs running Intel GPUs because the Intel HD Graphics engine uses dedicated hardware to implement support for the DXVA scaling API calls. AMD and NVIDIA apparently implement those calls using pixel shaders. In order to obtain a frame of reference, we repeated our benchmark process using DXVA2 scaling for both luma and chroma instead of the default settings.

LAV Video Decoder (QuickSync) + madVR (DXVA Scaling)
Stream GPU Usage % Power Consumption
     
480i60 MPEG-2 50.33 43.54
576i50 H.264 52.39 44.33
720p60 H.264 57.34 48.82
1080i60 H.264 62.63 55.52
1080i60 MPEG-2 62.34 55.21
1080i60 VC-1 62.06 55.51
1080p60 H.264 65.56 55.33

DXVA scaling results in much lower GPU usage for SD material in particular with a corresponding decrease in average power consumption too. Users with Intel GPUs can continue to enjoy other madVR features while giving up on the choice of a wide variety of scaling algorithms.

HTPC Decoding and Rendering Benchmarks: EVR / EVR-CP Software Interface: XBMC and JRiver Media Center 18
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  • Hardcore69 - Sunday, January 20, 2013 - link

    A lot of that GPU accelerated DirectX 11.1 stuff is used way more in the Modern UI than the deskto. And where were the power figures for the desktop version of the apps? Reply
  • ganeshts - Sunday, January 20, 2013 - link

    Which apps are you talking about in particular?

    The Netflix app is the only 'Metro-specific' app that we installed. For comparison, we have power figures for Silverlight and Windows 8 too (if that is what you mean by desktop version of the Netflix app).

    Everything else was the desktop version.
    Reply
  • mavere - Sunday, January 20, 2013 - link

    Is it possible to analyze where the Windows 8 power savings are coming from? In a couple tests, the benefits were equal to the entire TDP of some systems, and you'd think Microsoft would have advertised that aspect of Win8 more.

    I think I speak for most enthusiasts here when I say that the why and how is often more interesting than the what. :D
    Reply
  • ganeshts - Tuesday, January 22, 2013 - link

    I think a lot of that has to do with avoiding CPU loading (Silverlight), fully functional GPU accelerated decoding (again, not through Slverlight) and possibly DRM is handled through specialized CPU instructions instead of as a Silverlight component.

    The power differences seem to be non-existent in older systems as per other commenters, but, on modern CPUs / GPUs, it is very evident. So, I suspect a lot has to do with the updates made in the CPUs and GPUs in the last couple of years
    Reply
  • Midgetsaw - Sunday, January 20, 2013 - link

    This all very well and good but for me a htpc isn't any good without a tv tuner and windows 8 doesnt actually have media center. you have to contact ms to acquire it which is bs, all you have built is a glorified yt player, which you could have probably done with linux. Reply
  • lotharamious - Sunday, January 20, 2013 - link

    Do you have Windows 8 Pro? I'd bet you do.

    Free upgrade from Windows 8 Pro to Windows 8 Pro with Media Center until January 31.

    Go here:
    http://windows.microsoft.com/en-US/windows-8/featu...

    Give them a valid email address and enter the key they give you. Done. Windows 8 with Media Center.

    So difficult to "contact ms", my ass. You just want an excuse to hate. I understand, many are like you.
    Reply
  • Cygni - Monday, January 21, 2013 - link

    Ah yes, finally I can pay to upgrade my OS to a less usable HTPC version, then either jump through hoops (if its the next week and a half )or PAY EXTRA to restore completely un-upgraded functionality that came free with the version I upgraded from.

    Oh thank you Microsoft, you're truly a gleaming light.
    Reply
  • euler007 - Monday, January 21, 2013 - link

    I guess free isn't good enough for you. Should they e-mail you a check to earn your anonumous forum support? Reply
  • Golgatha - Monday, January 21, 2013 - link

    My time spent "upgrading" isn't free. Nor do I wish to experiment with Windows 8 further after already being maddened by it's ridiculous (for the desktop anyway) UI. I did try it for a few days and then I imaged back to my Win7 install. I like it better and all my programs work with it without issue. Reply
  • lexluthermiester - Monday, January 21, 2013 - link

    There are a great many of us who feel your pain. I gave The Consumer Preview a shot and I kinda warmed up to it. The Release Preview ruined that warmth. And and fairness, I gave the retail release a solid month before washing my hands of it. I work for one of the few remaining brick and mortar tech shops in my area and we had a meeting with the owners a couple weeks ago. We were all prepared to tell them that we were unwilling to sell or support Windows 8 any further. To our joy they gave us those very instructions. You should have seen the smiles spreading around the room. And we are not the only ones snubbing 8. Three other shops in this area are doing the same. It was left to me to inform the MS reps of the news. Funny thing, when I did they weren't at all surprised. They didn't argue or try to talk us out of it. They simply said they'd be happy to continue supplying us with 7. I asked one of them why they didn't put up more of an objection. He answer said it all; "You're not the only company to take this position. We know that 8 is not well received or liked". When Microsoft's own reps are talking like that you just KNOW something's wrong. I think I'll leave it at that. Reply

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