Re: Luma discussions

From: Bo Herrmannsen <>
Date: Mon, 20 Feb 2017 16:53:17 +0100
Message-ID: <>
i can throw in my 0.02 DKK here

while the 2 same rev chips can differ slightly as back in the day quality
control was a unmarked village in siberia.. also remember that all the
components arround it has tolerance too.

only sure way is to adjust each individual unit with a scope and freq.
counter (same scope used on all of course).

2017-02-20 16:49 GMT+01:00 Justin Cordesman <>:

> Only if it is repeatable, which I'd suspect it is not.  Things like color
> gamut being reduced on an old plasma, and quantization errors from the
> scaler are not indicative of actual performance by the C64.  It is also
> entirely possible for features in the scaler that are intended to do things
> like reduce compression artifacts or normalize analog noise will misbehave
> and generate new artifacts from legitimate signal or in attempts to reduce
> artifacts present in the original signal. Early ones are simple edge
> detection algorithms that do smoothing.
> Also, artifacts that are invisible under normal use are irrelevant, and
> not all signal defects are subjectively a problem.  For example, adding a
> small amount of analog noise to a noiseless video stream makes people score
> it as more detailed than the noiseless version when they are untrained
> viewers.
> Justin
> On Feb 20, 2017, at 17:34, smf <> wrote:
> On 20/02/2017 14:33, Justin Cordesman wrote:
> > I agree that the issue with that old article is clearly that it is
> describing behavior of the scaler and quantization of the signals coming
> out of the 64 and cannot be relied on to describe the behavior of different
> revisions.
> If putting it through a scaler makes display noise more visible that is
> usually hidden with a combination of your crt, your eyes and your brain
> then it is perfectly valid to use that to determine which revision is
> better than any other.
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Received on 2017-02-20 16:04:15

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