Outputting analog video to DVI involves some serious video processing - we're talking about converting the video from analog to digital, potentially converting it to at least 480p (I'm not sure that DVI supports 480i resolution, since all of the DVI-equipped DVD players I've seen are unable to output 480i), and then making sure the whole process remains HDCP compliant since you are now generating DVI signals rather than simply switching them. That's some mighty serious heavy lifting.