Haali's Media Splitter with ffdshow does work for playback of MP4 and MKV files in Vista & in media centre but thumbnails do not work* and the splitter causes other sorts of quirks in Vista media centre & Haali himself has said he has no plans to support Vista.
* You get black screens & the splitter causes Vista media centre longer to close than normal it seems along with bugs in thumbnails for other content as well.
I'm sure Nero would gain some customers & a lot of brownie points with the Windows media centre community if they did this
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