[mythtv-users] Correctly behaving 576i (or 480i) from vdpau-capable chip?

Christopher Kerr mythtv at theseekerr.com
Tue May 25 08:44:05 UTC 2010

On Tue, May 25, 2010 at 5:38 PM, Paul Gardiner <lists at glidos.net> wrote:
> I can't say with certainty yet because I don't yet have my ION board,
> but I'm pretty sure that it can because I have several sources and
> the 600Hz feature makes a striking difference on all of them. The
> motion becomes fluid in a way that I've never seen before. My girl
> friend raved about it more than I did: "How is it doing that? It's
> like being there", and then when I turned it off in an attempt to
> demonstrate that it was quite smooth even with out 600Hz: "TURN IT
> BACK ON!!". :-)
> It's not without a price. It definitely creates artefacts with
> complex objects moving across a complex background, the object
> can drag bits of background. The worst is a full screen pan
> with a semitransparent logo on the screen. The logo can become
> deformed. Most of the artefacts aren't very noticable unless you
> are looking for them, and I find them worth putting up with for
> the sake of the striking smoothness. I imagine others wouldn't
> though.

Indeed. Frankly I think it looks gross - much like the current crop of
3D movies, it makes the picture more striking at the cost of looking
wrong. IMHO, it's more of an "effect" than an "improvement".

While the TV may notionally manage a 600hz response time, in reality,
the DECAY time of images on both LCD and plasma displays is often
upwards of 40ms. Fortunately, it turns out that we can't actually see
the resulting motion blur, so it doesn't matter, but it renders the
issue of high refresh rate screens moot.

Taking the above into account, then, any differences you CAN see can
be attributed to the motion processing algorithms applied by the
display. Since they're interpolating data, it's unlikely that it
actually looks any better than the original, but if you happen to like
the effect, you might as well leave it turned on.

The only thing a 600hz display can do that a 100hz display can't is
properly display NTSC (30fps) PAL (25fps) and cinema (24fps) content
without mucking about with quality degrading techniques like telecine
or nasty hacks like PAL speedup. For that reason, and that alone,
"600hz" displays will probably become a worldwide standard within a
few years.

You (and others) may find
(and the further article linked at the bottom of that page)
interesting reading.

- Chris

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