[mark2929]

I have a seleco 350 from new and use a scart RGB when using the anamorphic mode on an 8 foot screen this gives an absolutely superb cinematic picture. Only in this mode though.

I find it hard to believe this quality is standard DVD so what I'd like to know is the projector using its 1000 tv lines and in some way line doubling even though its not supposed to have this function?

Why is this picture just so good?

TIA

Mark

[Barcoing Mad]

An RGB 576i DVD picture vertically compressed can look very good on a well set up CRT PJ. It's putting up on the screen what you're feeding it with the minimum of additional artefacts - in fact, a CRT PJ is very kind to the compression artefacts intrinsic to SD DVD.

You're not using '1000' TV lines, but you are resolving the maximum detail available in the SD image.

Now, you seem to be happy, so I'm not going to start pointing out things about your projected image that will remove your joy and set you upon the upgrade trail!!!

[mark2929]

The problem is I love home cinema and yet every demo I have seen (not including high end CRT) has paled compared to this. So this has kept me from upgrading because its so good. Its not like I'm being protected from seeing whats allegedly better I have a very good HD monitor etc. But there is no way the monitor can compare to the sheer cinematic quality from my 350.. Its just awesome and thats from plain old DVD's

I have to wonder then if measured resolution actually means that much on smaller screens until it's projected on a 40 foot screen for example. Maybe the reason there is a difference is not so much resolution as how the pj performs in other areas.

[Barcoing Mad]

Have you seen any HD on a good CRT PJ or digital?

[mark2929]

Not on a good CRT no.. Although I wouldnt expect my pj to match one but I cant imagine it would be such a huge difference except on wide open space shots where a lot of information is being shown. Close ups and medium shots I imagine would be fairly negligible. However that's just my opinion based on the fact I cant see anything on my pj that is a weakness apart from a slight blue convergence problem that you have to look for in one corner.

[Barcoing Mad]

Okay that's interesting. Which digitals have you seen? Were they showing HD? Returning to CRT...Does liquid-coupled as opposed to air-coupled lenses mean anything to you?

Oh, and welcome to the forum and a world of pain, I mean pleasure.

[mark2929]

Thanks for the welcome!

I can't remember the names of digital projectors only that the ones I have seen look awful.

I cant quite believe that my projector can be bought for a few pounds on ebay when the quality of modern projectors costing a few grand pales into insignifigence.. I'd like to move away though from my opinions and look for answers as to why this is the case.

Surely Im not the only person with a seleco 350 using the RGB input with anamorphic DVDs that knows how great this projector is.

[Barcoing Mad]

A CRT PJ can provide a very good picture, and people can spend far more and achieve far less with a digital - so you're perfectly correct.

However, you're talking to people who use Barco 1209s, Cine 9s, Marquee 9500 Ultras, Sony G90s with Crystallio and Lumagen scalers attached to Blu-Ray, HD-DVD and HD Sky sources. And of course there's the occasional scab like me who, having owned a Barco Vision II, went to a BD801s, BG801s, then a Marquee 7500, 8500 and finally 9500LC Ultra with a Crystallio 2 scaler has recently been playing with a digital (boo hiss) JVC HD750.

And I'm one of the saner examples of the breed who hang out here....any day now MadMrH will be putting crossed polars infront of his Cine 9s for 3d.

So I don't think you're the only person who knows what an air coupled 7" CRT PJ with 15kHz max scan looks like.

Read up a bit (visit Curt Palme's site) and keep making noise here - someone will take pity on you and show you a really nice set-up. Then be prepared to extract your wallet, as it'll be downhill for you from there on....

[mark2929]

I already did that years back I was more the hifi side and home cinema although. I never reached the echelons you guys appear to have done.. You have to have deeper pockets than me.. If anyone can suggest a better set up than the one I have using Blu ray I'd be interested to hear.

Mark

[Barcoing Mad]

Suggesting a better set up is easy, but it depends on your budget, your desire to build a system and ability at setting up and tweaking.

But first you should go and look at a decent system. There are a few of us up in Norfolk who run Marquee 9500's and JVC HD750/950's. And I'm sure there are people closer to you who'd be happy to give a demo - hobbyists, or perhaps Roland or MadMrH with more of a commercial interest can give some advice.

[Chris Frost]

Hi Mark,
1000 TV lines refers to the maximum resolving power of the lenses. That is something a little bit different from the resolution of the projector.


I think I know what you mean about the picture from your 350. I've set up more Selecos than I can remember and I've certainly encountered similar reactions from other owners. There are some links here and here

By current standards the 350 is a very modest projector. But the reason (IMO) why it produces such great results is that it gets the basics right. It doesn't mess up the image with fancy processing, and everything is working well within the capabilities of the chassis. Contrast that approach with so many of the digitals. The manufacturers try to produce "impressive" pictures by throwing a lot of technology at the problem. The result so often is an unnatural image with cartoon-like flat colour and overly sharp edges.

[mark2929]

Hi Chris

Yes that sounds right to me. In my setup sharpness is off.

The picture to me is just so good. My brother was so impressed he tried to buy a used projector from a football club I cant remember the name but it could never ever give an image like the Seleco could. Although it's only in RGB anamorphic mode that the Seleco can do this.

Mark

[mark2929]

I think I may have found something that I hadn't noticed before on page 69 of the manual near the bottom it states

RGB Input more than 1000 TV lines

It doesnt mention any other line in like svhs etc..

Why would it have a 1000 lines going in when the source is less and if so what happens to those lines not being used? Or are they being used.

[bxd]

Hi,

The "1000 tv lines per picture height" really refers to the horizontal resolution of the projector.

The tv lines term refers to how well the tv (or projector) can resolve an image going from a white to black signal (like a white picket fence against a black background) across the screen over a distance equivalent to the height of the picture (for a 4:3 aspect ratio).

Using these terms vhs could resolve ~240 lines and laserdisc would resolved ~400 lines, so 1000 picture lines suggests that the projector can operate at a resolution greater than the video sources available.

Brian

[mark2929]

Hi Brian

Yes I agree so if say DVD is 480 lines high and the projector can resolve 1000 lines in RGB then what is happening to all that blank space?

Mark

[bxd]

Hi,

Originally Posted by mark2929

Yes I agree so if say DVD is 480 lines high and the projector can resolve 1000 lines in RGB then what is happening to all that blank space?

No, not quite_ it not about picture height or scanning lines_ we normally consider a dvd picture as (say) ~720x480 (for ntsc). In terms of tv lines that would be ~75% of that value_ about 540 tv lines horizontally, but the vertical resolution would still be 480 (scanning) lines.

Remember, that there isn't any blank space on a picture. Across a single scan line on a crt, the voltage can go from high (100% white) to low (100% black or 0% white). The "line" resolution reflects how well (and quickly) the display can go from a full white signal to a full black signal (on black there is still a voltage there but it's not sufficient to energise the screen phosphors).

You could also consider it as a sine wave _ the peaks are full white and the troughs are full black. Your projector can "squeeze" 1000 of those peaks and troughs (500 of each) across the screen in a distance equivalent to the picture height.

Camera lenses are tested in a similar fashion. If you draw black vertical lines onto a bit of card and make them finer and finer (but still as discrete lines), it's all about the ability of the lens to "see" those divisions between the lines. On a crt, it's all about the ability of the projector to change voltage quickly enough (within the period of a single scan) so that you can see those individual vertical lines.

Brian

[mark2929]

Hi Brian

Thanks! Although I am a little confused. Does that mean my Seleco is resolving 1000 TV scan lines in RGB mode Are TV lines not the same as the 480 lines used to describe its vertical resolution?

Mark

[BobbyBlaze]

As posted in another recent thread, I rang Owl up about this years ago when I had a Seleco and they admitted the "1000 lines" was a theoretical maximum based on a 25i signal (12.5 frames per second) to fit it into the 15.5khz limit of the PJ. So (theoretically, if such a source existed) you could induce your very own epileptic fit to a very flickery, hi-rez decaying picture. Not that the plastic lenses on a seleco could resolve such sharpness, anyway.

Pure marketing babble, basically. If you want 1080i you should look elsewhere than a Seleco to achieve it.

[mark2929]

Hi Bobby

Your saying the 1000 TV lines in the manual is a reference to 25i??

Still doesnt explain why the manual only mentions RGB?

This really is becoming unexplainable and Im starting to wonder now if there is something special about the 350's Scart RGB in anamorphic. Something I've wondered for a few years now.

Mark

[bxd]

Hi,

Originally Posted by mark2929

Are TV lines not the same as the 480 lines used to describe its vertical resolution?

No they are not the same.

Remember for crt, the vertical resolution is made up of a series of horizontal scan lines (480 visible picture lines for ntsc, 576 for pal and ~720 or ~1080 for HD). The horizontal resolution is based on the number of transitions from white to black that the electronics of the projector are able to make along a single scan line. The lines of tv resolution are measured along the scan line and for a distance that is equivalent to the height of the picture.

As I said_ consider a tv picture of a picket fence (or a white comb) against a black background.

The fence posts (white) are vertical on the screen against a black background (also vertical). In order to show the fence the horizontal electron beam has to go from one extreme of it's voltage range (peak white) to the other extreme (blackest black) as it scans along the line. The quality of the electronics controls how many times the projector can do this (go from black to white) along the length of the scan.

If I draw a line like this:

TTTTTTTTTTTTTTTTTTTT

Let's say that this run of the letter T is constructed by 4 horizontal scans along the face of the crt. Initially, along the top bar of the T (all black) the the beam is simply at a low voltage for the whole scanning pass and it shows up as a horizontal black line
On the vertical part of the T however, the scanning beam has to go from black to white (and back again), to properly show the vertical structure of the letters across the scan line. In the example above it's having to do that ~20 times in a scan and then repeating that twice more to complete three scans.

If you do that with a series of vertical lines:

|||||||||||||||||||||||||||||||||

then the finer the lines gets,

|||||||||||||||||||||||||||||||||||||||||||||||||| ||||||

then the more often, the projector has to do that transition and the greater the strain on the electronics.

On a fixed pixel display the horizontal resolution is determined by the number of pixels that can be individually lit. As you look along a horizontal line of pixels you could have one on full (white) with the next one off (black) to make up your horizontal resolution. Since a crt has no pixels (just a smooth phosphor surface) the electron beam has to be turned on and off to make up that resolution.

Brian

[bxd]

Hi,

Sorry to mention it but BobbyBlaze is confusing things a bit.

The resolution in "TV lines" has is nothing to do with the vertical resolution of the projector, so it doesn't affect the ability to do 1080i or 480i.

The vertical resolution of the projector is determined by the number of horizontal scan lines that make up the picture, so 15.5kHz only represents a maximum of a 625 line picture.

The reference to rgb simply relates to being able to feed the crt tubes directly without wasting any time with video processing, so an rgb input will be the best signal to send to the projector. My old Sony 1031QM has a resolution of 1100 TV Lines on it's rgb inputs and 650 TV Lines on it's video inputs. Since it can accept a horizontal frequency up to 36kHz, it could do 1080i.

Guys_ remember it's really easy to get confused by all of this. It's similar to the situation where we've heard people (and some serious, professional people) get confused about this. In vhs days, people would say that vhs was "240 lines" and then go on to suggest that a vhs recorder only recorded 240 lines of the 625 picture lines. That's complete "bull-poo". The vhs recorder would record all 625 lines that make up the structure of the picture but could not record the full number of "transitions" (~400) that made up the horizontal resolution of the picture.

Brian

[mark2929]

Hi Brian

I'm still confused by the science but I think the gist of what your saying is the projector will resolve whats its being given and will do this on my projector up to 1000 lines. So I cant be getting more lines than the DVD will allow in the form of some kind of line doubling.

It wont do more than the info being supplied though.
Although I can imagine in anamorphic mode it's really making it all count.

So does this mean then that an interlaced HD signal through RGB would resolve more lines?

Mark

[bxd]

Mark,

You're mixing up the horizontal and vertical resolution of the projector.

Line doubling relates to the vertical resolution of the display but your display isn't capable of doing that.

Remember how a projector works:

Just like drawing lines across a sheet of paper, the display scans an electron beam horizontally across the face of the tube. For a standard interlaced video picture projector it will scan the odd lines first (1,3,5 ...) and then do the even lines (2,4,6 ...). Doing that, the display makes two 'fields' that make up the picture. The vertical resolution (top to bottom of the display) of the projector is determined by the number of horizontal lines that make up the picture. On your (video only) projector that is a maximum of 625 lines, of which only around 576 lines are active picture lines.

Line doubling (deinterlacing ... I'm not going to get into the complexities of that) involves the electronics of the projector working twice as hard, so that it can display all the picture lines (1,2,3,4,5 ...) in the same time that it would normally take to do a single field.

I suspect that the 'anamorphic mode' simply squeezes the height of the picture but it doesn't change the scan rate or vertical resolution within that height.

In the picture below I've drawn a "crt picture" of two white vertical posts. The image is made up from 8 horizontal scan lines, so that is the vertical resolution of the projector_ 8 lines is all you have.

1_______________________________
2_______________________________
3___ __ ________________________
4___ __ ________________________
5___ __ ________________________
6___ __ ________________________
7___ __ ________________________
8___ __ ________________________

The horizontal resolution is determined by how many times the display can go from peak white to black during each scan. In this case (on lines 3 to 8) the display has done that twice. The better the display can do this, then you can see progressively thinner posts. Once you go beyond the horizontal resolution, then the posts will blur into each other.

I'm not quite sure what you mean by :

"So does this mean then that an interlaced HD signal through RGB would resolve more lines?"

Not on your projector_ it can't handle a HD scan rate.
Since an HD picture is made up of 1080 horizontal picture lines, then this represents an increase in the vertical resolution on the display (if the display can handle it).
The horizontal resolution (usually given as 1920) provides more detail (possible transitions from white to black) along the length of each line. Again this is dependent on the abilities of the display to do this. On a crt projector, this is only available of top end machines with 9 in tubes.

Going right back to your original post_ no your projector isn't using all of it's "1000 TVlines" resolution because dvd doesn't have that horizontal resolution. Just sit back and enjoy it.

Brian

[mark2929]

Hi Brian

Thanks for your post. I wish I could properly understand what you mean!

Anyway..

I've been looking at the hdfury
hdfury2 hdfury2 official distributors [] - £144.00 : HD Fury, Online Uk Store

And wondered if using this with a blu ray player would lead to increased defination?

Mark

[bxd]

Hi,

I'm sure someone else will put my explanation across in a simpler manner.

However, I'm sorry to say that your projector can't accept the output from a HD-Fury so it won't work. Your display doesn't support 720p, 1080i or 1080p. It only supports 480i (525 line ntsc) or 576i (625 line pal).

Your projector is limited to video resolution only so you can only use the scart, s-video or composite video output from a bluray player (or component output if you have component inputs). That will give you a standard definition picture so you can't increase the resolution (or definition) from your display.

Brian

[mark2929]

Thanks Brian

I still dont understand why the manual should mention it has 1000TV lines on the RGB input.

[bxd]

Hi,

Do a google search on TV Lines and you'll find some diagrams that are better than mine. Expressing horizontal resolution as TV lines is a 'bad' term to use, so it's not used very often with todays fixed display devices.

As I've been trying to get across, the 1000 TV Lines are not the same thing as the number of horizontal lines that make up the picture. Your projector can't produce any more (horizontal scan) lines than 625.

However, each individual scan line can be split by turning the electron beam on (to give you white) or off (to give you black) up to some maximum figure. Doing that gives the visual appearance of a series of white vertical lines.

I've drawn a single white vertical line on the diagram. On a crt that would be done by turning the electron beam on for a tiny fraction of a second as it passes along scan lines 2,3 and 4.

1_____________________________________________
2___ _________________________________________
3___ _________________________________________
4___ _________________________________________
5_____________________________________________

Your projector can quickly turn the electron beam off and on, to give the appearance of up to 1000 vertical lines across the width of the screen.

So your display can "resolve" up to 1000 vertical lines across the width of the display but within a single scan line.

Since it's all done within the individual scan lines you are not increasing the vertical resolution (which stays at 625 lines _or 5 lines in my example above).

Just ignore what the manual says about TV Lines.

To put you on the right track have a think about the following:

If you have a black tv picture, how is it possible to show a vertical white line on the screen when the picture is made up by a series of lines which are ONLY scanned from left to right and top to bottom while remaining horizontal?


Brian

[mark2929]

Hi Brian

Okay I think I'm getting there, so the TV lines are not actually lines as I would know it in fact The projector can never show more than 480..

Does this still mean that a Bluray signal would not give an improvement to the seleco 350's picture quality through the RGB scart using a convertor.

Mark

[bxd]

Hi,

Originally Posted by mark2929

Okay I think I'm getting there, so the TV lines are not actually lines as I would know it in fact The projector can never show more than 480..

Does this still mean that a Bluray signal would not give an improvement to the seleco 350's picture quality through the RGB scart using a convertor.

Yes, you're getting there. The projector can never show more than 625 HORIZONTAL lines (576 visible lines) as it doesn't have the power supply and electronics to do so. You would need to change your projector.

The output from a blu-ray player on it's standard definition outputs (composite video or s-video or rgb or component video) will be no better than you currently get from your dvd player. Similarly, your projector can't accept any of the HD inputs from the blu-ray player, nor is it capable of displaying any HD material.

You can still play blurays on your projector but you just won't get any of the (HD) benefits of doing so. On the other hand, you're building up a stock of discs (rather than dvds) which you can use in the future when you replace your current display.

I also have a fairly modest 7in projector (Electrohome ECP4501) but it's capable of displaying 1080i or 720p and can just manage 768p so I'm not as restricted as you are with a video only display.

Brian

[mark2929]

Okay thanks Brian. Looks as if I'll have to forget the bluray player for a while!

Mark