[mythtvnz] Feedback requested on an article on Digital TV

[Steve Hodge]

On 10/7/06, Steven Ellis <steven@openmedia.co.nz> wrote:
> Steve Hodge wrote:
> > This is certainly never been the case for me. Though One and 2 look
> > better via DVB-S through MythTV (connected to a plasma via VGA cable)
> > than via Sky (connected via SVideo). But the technology is the same.
> > There's no guarentee that FreeView will look any better. You're
> > assuming that the FreeView partners will do a better job or at least
> > allocate more bandwidth than Sky do now.
>
> Technology is the same, but the bit-rates are way different.

Incidentally, do you think Sky decoders will be able to pick up the
FreeView channels? Technically they should be able to, right?

> 1. Sky doesn't use 720x576 for all of its channels (or at least they didn't)

That's poor. Which channels, do you know?

> 2. What is Sky's average bit rate vs FreeView ? FreeView appears to be
> around 4.8Mb
> 3. Sky only does anamorphic wide-screen on selected channels (at present).

Is FreeView going to be entirely widescreen?

> 4. Not all Sky boxes have component - I agree it is a lot better, but
> not as good as DVI/HDMI/VGA

SCART RGB should be all but indistinguishable from VGA. The only
difference is that VGA has separate horizontal and vertical sync
signals and SCART RGB has a combined sync signal. Certainly my
plasma's manual lists SCART RGB as being as good as DVI-D and VGA, and
better than component.

> 5. I don't know anyone who even realises you can feed a Sky box over
> component, never mind actually doing it.

I don't know anyone doing it, but I have seen the odd mention here and
there. Part of the problem is that it's not a component signal as I
thought and not many TVs have full SCART input (at least not many CRT
TVs). However, if people can't be bothered getting the best signal out
of their existing equipment, that says a lot to me about how much they
care about video quality.

Another issue, at least for me, is that you can't set one of the SCART
outputs to RGB and have the other SCART output on S-Video. The best
you can do is one RGB and one composite or both S-Video. The S-Video
connection to my Myth box is far more important than having RGB to the
TV for the very occassional time I watch that way.

Incidentally, according to their website the MySky decoder does do
component out as well as RGB.

> 6. Can you record component ? I don't know of any reasonably priced
> capture cards that can do component.

I don't know of any either. It's useless for MythTV, I agree. But my
argument is that the difference between Sky Digital and FreeView won't
be that great - i.e. that Sky Digital (on the major channels if you
like) is a reasonable approximation of what FreeView will have to
offer for the average person. It could be as good as DVD quality, but
we won't know until we get it. For MythTV, I agree that FreeView will
be a significant improvement.

> What size and type of screen are you viewing on. A standard CRT up to
> 32" is very forgiving of SkyTV. Once you move onto LCD and Plasma at
> 40"+ the difference is huge.

I'm using a 42" plasma. It's a low end one (852x480) so it's not an
HDTV display. I agree that Sky Digital doesn't look that flash, but
there is no way it is worse than broadcast.

I got a SCART cable and did some testing today. DVB-S through MythTV
is definitely softer than Sky->TV using either S-Video or RGB. This is
quite likely due to the settings on my Myth box. Unfortunately I can't
do a side by side comparison of Sky's S-Video and RGB outputs (due to
the above mentioned limitations). I also have no way of viewing the
TVNZ's DVB-S output except via MythTV.

> The bit rate on the wide-screen test channel is usually pretty damn
> high, way above normal DVD bit rates.

How high? Unless it's much higher than the 4800 kbit/s you mentioned
earlier I doubt there will be many people who will be able to tell the
difference between that and DVD.

Certainly TVNZ Wide via MythTV does not look as good as DVD on my
system, though that could be the fault of my MythTV setup.

Steve