[opendtv] Re: Blue Ray has competition
- From: "Dale Kelly" <res0xtey@xxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Fri, 17 Sep 2004 18:20:57 -0700
Barry, sorry for my lateness of response but have been out of touch for
several weeks.
You wrote:
>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.
No, I didn't discount the number of scan lines per frame as a factor in
determining visual superiority. That, coupled with the added video bandwidth
provided by an 8Mhz channel, provides a generally superior image display.
> 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.
What I attempted to say is that the PAL chroma modulation scheme has nothing
to do with the improved quality in 50 Hertz countries. In fact, PAL
deteriorates the overall color 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?
If you remove the PAL feature from current 625 line systems, you have
created a 625 line NTSC system. Such a change could result in an overall
image quality improvement, viewed on a properly adjusted TV display.
Unfortunately US NTSC can not produce a 625 line frame rate due to the 60
hertz power line frequency. Therefore it could never look quite so good as
the 625 system, even if 8Mhz channels were available.
However, if you view US produced 601 digital video on a DTV system, using a
720P or 10801 display, it is superior to either analog color systems.
----- Original Message -----
From: "Barry Wilkins" <Barry.Wilkins@xxxxxxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Sunday, August 29, 2004 2:10 PM
Subject: [opendtv] Re: Blue Ray has competition
> 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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>
>
> =20
> =20
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