NVIDIA’s GeForce GT 220: 40nm and DX10.1 for the Low-Endby Ryan Smith on October 12, 2009 6:00 AM EST
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A Better HTPC Card: MPEG-4 ASP Decoding & LPCM Audio
Along with the addition of DirectX 10.1 functionality, the latest members of NVIDIA’s GPU lineup have picked up a couple of new tricks specifically geared towards HTPC use.
The first of these is a newer video decoding engine. Officially NVIDIA is moving away from the VP* moniker, but for the time being we’re sticking to it as we don’t have a better way of easily differentiating the feature sets of various video decoding engines. NVIDIA’s vendors are calling this VP4, and so are we.
Successive VPs have focused on adding support for additional video formats. VP2 had full H.264 decoding, and VP3 (which never made it into a GTX 200 series part) added VC-1 decoding. For VP4, NVIDIA has added support for full decoding of MPEG-4 (Advanced) Simple Profile, better known as DivX or XviD. With this addition, NVIDIA can now offload the decoding of most of the MPEG formats – the only thing not supported is MPEG-1, which as the oldest codec is trivial to decode on a CPU anyhow.
To be frank, we’re a bit puzzled by this latest addition. By no means are we unhappy (we’ll always take more acceleration!), but MPEG-4 ASP isn’t particularly hard to decode. Even an underclocked Nehalem with only a single core (and no HT) enabled can handle HD-resolution MPEG-4 ASP with ease; never mind what even a low-end dual-core Pentium or Celeron can do. This would be a good match for the Atom, but those almost always use integrated graphics (and Ion isn’t slated to get VP4 any time soon). So while this addition is nice to have, it’s not the kind of game changer that adding H.264 and VC-1 were.
The unfortunate news here is that while the hardware is ready, the software is not, and this is something that caught us off-guard since these parts have been going to OEMs since July. NVIDIA has yet to enable MPEG-4 ASP acceleration in their drivers, and won’t be doing so until the release 195 drivers. So at this point we can’t even tell you how well this feature works. We’re not pleased with this, but we’re also not particularly broken up about it since as we just mentioned the cost of CPU decoding isn’t very much in the first place.
On a final note with video decoding, one of NVIDIA’s marketing pushes with this launch is touting the fact that they have been working with Adobe to bring video decode acceleration to Adobe Flash 10.1, and that the GT 220/G 210 series are well suited for this. This is going to be absolutely fantastic to have since Flash Video is a CPU-hog, but Flash 10.1 is still 6 months (or more) away from being released. More to the point, as far as we know this is being implemented via DXVA, which means everyone else will get acceleration too. And notably, this is only for H.264, as VP6 (the older Flash Video codec) is not supported in hardware on any card.
Moving on, the other new HTPC feature is that NVIDIA has finally stepped up their game with respect to HDMI audio on cards with discrete GPUs. Gone is the S/PDIF cable to connect a card to an audio codec, which means NVIDIA is no longer limited to 2-channel LPCM or 5.1 channel DD/DTS for audio. Now they are passing audio over the PCIe bus, which gives them the ability to support additional formats. 8 channel LPCM is in, as are the lossy formats DD+ and 6 channel AAC. However Dolby TrueHD and DTS Master Audio bitstreaming are not supported, so it’s not quite the perfect HTPC card. Lossless audio is possible through LPCM, but there won’t be any lossless audio bitstreaming.
Finally, we’re still waiting to see someone do a passive cooled design for the GT 220. The power usage is low enough that it should be possible with a dual-slot heatsink, but the only cards we’ve seen thus far are actively cooled single-slot solutions with the heatsink sticking out some.