We should demand it!

Discussion in 'General TV Discussions Forum' started by Zacabeb, Jul 18, 2002.

  1. Zacabeb

    Active Member

    Jan 17, 2002
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    I decided to play (so to speak) with the service menu in my 32PW9616 to try and switch off LTP. LTP is a feature that stretches areas of differing contrast toward each other, so to shrink the transient time. This sharpens the picture.

    LTP is a very nice thing in principle. The traditional way of sharpening pictures is through peaking. That involves subtracting areas around transients from the transient itself. That increases the contrast in transients and can appear to sharpen the picture, but it can also cause ringing.

    The problem with the 32PW9616 is that LTP is performed by a universal analog processor called TOPIC, whose operation can only be configured so much. It seems it is optimized for 4:3 50Hz sets. At 100Hz, LTP causes distortion with smooth areas getting unnaturally sharp edges.

    100Hz doubles the output frequency, and rescaling the picture down to 4:3 pillarbox to fit inside a 16:9 screen means the relative frequency of picture details is increased by another third. Thus, any frequency input will be raised with 167%. This means the frequencies the TOPIC responds at, are actually part of much lower frequency picture content.

    And therefore it fails to do any good, it just makes the picture look unnatural.

    LTP can be turned off in the service menu, and doing so allows for a smoother and more natural image. However, it can only be turned off together with the whole package of 'picture improvements', including motion compensated DNR and full Active Control. The light sensor can no longer be used, and must be turned off separately. Otherwise the Active Control menu leaves static character garbage from 'dead' options listed, should you enter it.

    This means, once picture improvement is turned off, you can no longer use DNR. You can turn Active Control on/off, which will use the PICNIC processor's simple coring for DNR. Turn Auto TV off in the dealer options and you can switch DNR on/off (still PICNIC coring) but not use Active Control at all. Good riddance, but motion compensated and variable DNR is actually useful.

    So what is the point I am trying to make?

    Features that are only fluff put in there to impress windowlickers can not be turned off proplerly in your very own home, even though it would be simple for manufacturers to permit this.

    If Joe Codschnitzel-Ultravox or Jane S:t Redbeardstreasurecoffin think SVM and LTP are gifts from heaven, let them have'em. But the rest of us should not suffer!

    We should demand all and any Duckburg features to be switchable. We need not suffer digital artifacts. If they could be turned off, everyone of us would be happy.

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