oo_void
18th February 2005, 21:00
I orginally posted this query over at www.xpmce.com, trying to solve an issue I have with my new Media Center 2005 box, but the users there have been less than responsive (what's 4:2:2 ;) ). Anyways, I thought I'd give this community a try also ...
I’m new to all this MCE stuff, so forgive me if this sounds like a dumb question… I’ve put together a homebrew MCE 2005 system that runs great (for the most part). The machine runs an ATI Radeon 9550 with the 5.2 MCE Catalyst drivers and a Hauppauge PVR-150 capture card, being the relevant pieces of hardware for this issue. Seeing how everyone seems to be raving about the Nvidia MEPG-2 decoder, I thought I’d give it a try.
Unfortunately, the Nvidia decoder, along with all the others I’ve tried except Cybervideo (picture quality is sub-par) and DScaler (the one I’m currently using, though not fully compatible) exhibit what would best be called color space conversion issues.
The PVR-150 captures video using the 4:2:2 color space (from what I understand), meaning chroma channels are captured at half the resolution of the luma channel. This is all fine and dandy and part of the nature of video compression. When converting the 4:2:2 colorspace into RBG for output to the display, one would normally expect an MPEG-2 decoder to resample/resize the chroma channels to match the size of the luma channel, resulting in an image with smooth areas of color. Your standalone DVD player does it, and so does DScaler within my MCE environment… but the Nvidia and Intervideo decoders don’t.
What I get when I attempt to play back content on my MCE machine is “boxy” areas of color information… stair stepping or aliasing. It looks as if no processing is being done to rescale the chroma. I know this can’t be the correct behavior or else everyone would be complaining about sub-par image quality. Anyone have any suggestion as to what I’m doing wrong (something related the display drivers maybe? DxVA or VMR setting off?).
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oo_void
I’m new to all this MCE stuff, so forgive me if this sounds like a dumb question… I’ve put together a homebrew MCE 2005 system that runs great (for the most part). The machine runs an ATI Radeon 9550 with the 5.2 MCE Catalyst drivers and a Hauppauge PVR-150 capture card, being the relevant pieces of hardware for this issue. Seeing how everyone seems to be raving about the Nvidia MEPG-2 decoder, I thought I’d give it a try.
Unfortunately, the Nvidia decoder, along with all the others I’ve tried except Cybervideo (picture quality is sub-par) and DScaler (the one I’m currently using, though not fully compatible) exhibit what would best be called color space conversion issues.
The PVR-150 captures video using the 4:2:2 color space (from what I understand), meaning chroma channels are captured at half the resolution of the luma channel. This is all fine and dandy and part of the nature of video compression. When converting the 4:2:2 colorspace into RBG for output to the display, one would normally expect an MPEG-2 decoder to resample/resize the chroma channels to match the size of the luma channel, resulting in an image with smooth areas of color. Your standalone DVD player does it, and so does DScaler within my MCE environment… but the Nvidia and Intervideo decoders don’t.
What I get when I attempt to play back content on my MCE machine is “boxy” areas of color information… stair stepping or aliasing. It looks as if no processing is being done to rescale the chroma. I know this can’t be the correct behavior or else everyone would be complaining about sub-par image quality. Anyone have any suggestion as to what I’m doing wrong (something related the display drivers maybe? DxVA or VMR setting off?).
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oo_void