[opendtv] Re: Blue Ray has competition
- From: "Barry Wilkins" <Barry.Wilkins@xxxxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 30 Aug 2004 09:10:58 +1200
Thankyou Dale for your highly informative reply. I have scrutinized this
in detail. You do say that there is visual superiority in relation to
the 625 line system. But you discount the number of lines as having the
major influence. To me it is immaterial that the H scan rate is
approximately the same. I cannot get over the reality that there is an
extra 100 lines of information, and this must create detail which would
otherwise not be so resolvable. You have dicounted the relationship
between required bandwidth and resolution. I accept that there is a
larger frame rate for US NTSC and this requires bandwidth also. So, the
implication is that both systems could exist on 6 MHz bandwidth channels
with comparable quality. Can it?
My understanding is that people in the US like to say that 60 Hz NTSC
has higher temporal resolution than 50Hz PAL. That may well be correct.
However, as much content tends to be static, the temporal resolution
improvement is likely to be insignificant. Even when the camera is
panning the image of interest generally remains fairly stationary. The
blur of background content tends to be immaterial to the observer in
these cases. If I have this concept in error then I welcome any reply to
the contrary.
Much of what you say is about challenging cause while accepting the
effect, i.e. that the end result is that 625 line PAL can and will
generally result in superior image quality.
Are you also implying that if US NTSC was transmitted on 8MHz channels
then it would be as good as PAL is in Europe, or better perhaps?
Barry Wilkins =20
-----Original Message-----
From: Dale Kelly [mailto:res0xtey@xxxxxxxxxxx]=20
Sent: Saturday, 28 August 2004 5:58 a.m.
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: Blue Ray has competition
>Can I remind those people that had the USA had 625 line PAL for the
last
50 years there would be no motivation to go to HDTV because resolution
is
> quite acceptable on the average screen.
The PAL (Phase Alternate Line) feature in the 625 line system has=20
significantly less to do with that system's visual superiority than do=20
certain other unrelated system features. The 625 PAL system, being
closely=20
modeled after 525 NTSC, generally gains it's superiority from two major=20
differences which have little to do with clever design.
1. The 625 line per frame feature, which is responsible for improved=20
vertical resolution, is simply a result of it's ~50 Hz V scan rate,
which is=20
tied to the 50 Hz power line frequency found in most (all?) PAL
countries.=20
The H scan rate for both systems is nearly identical (about 15.7 Khz).=20
However, when a scanning system refreshes at 50 Hz the scan rate per
frame=20
is ~625 lines. When the frame rate is refreshed at 60 Hz, the resultant
scan=20
rate it is ~525 lines per frame.
2. The RF bandwidth allocated to a TV channel in PAL countries is=20
generally 7 to 8 Mhz rather than the 6 Mhz allocated in North America.
This=20
additional RF bandwidth is a very significant contributor to the visual=20
superiority but again, has no direct relationship to the 625 PAL systems
design.
The PAL feature itself is indeed a clever design change which eliminated
the=20
need for a HUE/Tint control and which was an important feature in
earlier=20
color TV set design. In more recent years advancements in receiver
design=20
have rendered this feature to be of lesser value. The addition of the
PAL=20
feature did reduce chroma V resolution and also create a relatively=20
significant problem for program producer in that the resultant 8 field
color=20
frame was responsible for post production difficulties and was a major=20
factor in the early adoption of component video systems by PAL
countries. To=20
be accurate though, component systems brought much than that to the
table.
( I believe the above statements to be accurate but are based upon=20
experiences from many years ago so please chime in if required for
clarity!)
Regarding the poor quality you have noted on imported NTSC product, I
see=20
two possible culprits in addition to the lesser native quality of the
525/6=20
MHz video system:
1. Poor standards conversion - not all such hardware is created
equally.
2. Failure to request that the product be delivered in the 601 digital
video format. Most all major syndicated product is available in that
format=20
and is generally it's native format.
----- Original Message -----=20
From: "Barry Wilkins" <Barry.Wilkins@xxxxxxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Thursday, August 26, 2004 2:15 PM
Subject: [opendtv] Re: Blue Ray has competition
> Yes John, that is true. But it is also true that I am in New Zealand,
> not Australia. However, it is common to find non region specific DVD
> players here also. So, if the regionalization mechanism can be
> circumvented without bother then why maintain it?=3D20
>
> I am intrigued to know this. When this diabolical concept was devised,
> was there any say from representatives of any of the "lesser" regions
in
> deciding the hierarchy of those regions?
>
> It may be hard for many in the US to appreciate, but I do not wish to
> import region 1 NTSC DVDs. The only advantage would be that there may
be
> extra time for documentary material after the movie. The disadvantage
is
> inferior quality. The lack of perception of this reality is all too
> clear in many comments made by certain people on this forum. This
> accounts for statements made implying that the DVB-T standard as
> implemented in Europe is backward as it is not geared to HDTV. Can I
> remind those people that had the USA had 625 line PAL for the last 50
> years there would be no motivation to go to HDTV because resolution is
> quite acceptable on the average screen. I can tell you that watching
the
> Olympics on my 42" AliS plasma screen at a distance of 3 meters is
very
> satisfying, picture quality wise. It is received in my home via
> satellite and the picture is subjectively at least as good as a well
> rendered DVD.
>
> Furthermore, as far as picture quality is concerned, there is a marked
> difference in quality of entertainment material received from the US
> versus that from the UK. A typical example would be the comedy
"friends"
> which is replaying here. The colour is very poor, the definition is
poor
> and it is only watchable because it is such a remarkably good comedy.
>
> So, back to my original grumble. I am happy to import region 2 PAL
DVDs
> but even region 2 has a significantly reduced subset of the US DVD
> selection.
>
> Regards
> Barry Wilkins =3D20
>
> -----Original Message-----
> From: John Shutt [mailto:shuttj@xxxxxxxxx]=3D20
> Sent: Friday, 27 August 2004 5:27 a.m.
> To: opendtv@xxxxxxxxxxxxx
> Subject: [opendtv] Re: Blue Ray has competition
>
>
> Barry,
>
> At least in Australia it is legal to own a DVD player that has the
> region
> codes disabled.
>
> John Shutt
>
> ----- Original Message -----=3D20
> From: "Barry Wilkins" <Barry.Wilkins@xxxxxxxxxxxxxx>
>
>
>> While on the topic of new DVD standards, can anybody tell me if there
>> will be imposed an idiotic, unnecessary and entirely unfair regional
>> system for these new HD pre-recorded discs. I am saying this because
I
>> come from the forth "world"(region)area, which does not get many of
> the
>> DVDs you in the USA get, even after the original movie has been
> released
>> in theatres for years.
>> An example is "The Mission", which even now I had to import from
> region
>> 2. You have had this release on DVD for how long?
>>
>> Barry Wilkins
>
> =3D20
> =3D20
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