Samsung SP50L7HX pixel perfect from HTPC !!

Very nice post Kableman (as usual). I got some time today so I tested for first time the HTPC and 1:1 thing. Just 2 words :Incredible PQ !!! HD demos or games are so beautifull !
For me 60hz initially was underscanned, and I had to tune the 16/9 psize in order to fill completelly the viewable screen. It was not yet 1:1 of course. So I tested the PIP trick and it worked !!! but then all the previous screen size ajustments with Psize overwriten. Also there is a slight overscan exactly as yours. Tuning again with psize to reduce the screen size unfortunatly removes the 1:1. Any clue ?
 
A quick followup. I've been asked by Samsung UK to provide photos demonstrating this problem, which I have now done. So, looks like they are looking into this problem, and taking it seriously, which is excellent service from Samsung, I'm impressed. I've also sent a link for this discussion thread to the "Product Specialist" looking into the problem.

Photos are at the bottom of this page - http://gray.homeip.net/sp46.htm

And with all the overscan we're seeing, doesn't this mean that these DLP TVs are not really 1280x720 displays, but something less, somewhere around 1250x700. If so, how can they be classed as HD-Ready? HD-Ready requires a minimum native resolution of 720 physical lines in wide aspect ratio. Quite clearly these DLP TVs have a native displayable resolution of less than 720 lines.
 
That depends on whether or not the HD resolutions include an overscan to allow for broadcast - you are assuming that the HD resolutions are PC resolutions and are completely visible. It would not suprise me if all TV's that claim to be HD ready will have an overscan - which most likely won't be a problem as the movies and programmes they show will allow for this. I don't know but I work with some guys who are heavily into the broadcasting video standards (as they are building some kit for themeselves) and the standards include an overscan to obscure an area around the edge of the image which is intended to include additional information and simply untidy flickering.

Most plasmas, including the lastest HD Ready Panasonics, actually only support 1024x768 when connected via PC and yet they are still HD(TV) Ready.

Its not the overscan that's the problem its the lack of 1:1 pixel - without the tweaks. It's good to here that they are looking into it though :smashin:

Cheers
KableMan
 
KableMan,
whatever is the problem, overscan or luck of 1:1 pixel mapping - these DLP tv's unable to show 720 lines.
The SD plasmas have 480 lines resolution and even if they have HDMI inputs they called HD compatible.
HD plasmas with 1024x768 are HD Ready because in rules it is not mentioning the horisontal resolution. only vertical.
My Sagem crops 4 pixels from top and bottom and the rest is 1:1.
Another point is - will we notice it? NO. with PC on screen yes, we see it but with TV we will not notice it. :hiya:
 
cjgpers said:
A quick followup. I've been asked by Samsung UK to provide photos demonstrating this problem, which I have now done. So, looks like they are looking into this problem, and taking it seriously, which is excellent service from Samsung, I'm impressed. I've also sent a link for this discussion thread to the "Product Specialist" looking into the problem.

Photos are at the bottom of this page - http://gray.homeip.net/sc200.htm

And with all the overscan we're seeing, doesn't this mean that these DLP TVs are not really 1280x720 displays, but something less, somewhere around 1250x700. If so, how can they be classed as HD-Ready? HD-Ready requires a minimum native resolution of 720 physical lines in wide aspect ratio. Quite clearly these DLP TVs have a native displayable resolution of less than 720 lines.

wel thumbs up for them listening - my 50" sammy is due in morning - its replacing a 42" hitachi and I have to say every comment I made to Hitachi regards lack of 720@50 support on my Plasma fell on deaf ears

so this is encouraging
 
Snap said:
KableMan,
whatever is the problem, overscan or luck of 1:1 pixel mapping - these DLP tv's unable to show 720 lines.
The SD plasmas have 480 lines resolution and even if they have HDMI inputs they called HD compatible.
HD plasmas with 1024x768 are HD Ready because in rules it is not mentioning the horisontal resolution. only vertical.
My Sagem crops 4 pixels from top and bottom and the rest is 1:1.
Another point is - will we notice it? NO. with PC on screen yes, we see it but with TV we will not notice it. :hiya:


Well, I think the problem, most for me, is to have 1:1 so the TV does not scaler och ANYTHING with the image. If I get a 5500$ Crystalio II video processor, I don't want the image from that to be scaled again! :lesson:
 
Snap said:
KableMan,

whatever is the problem, overscan or luck of 1:1 pixel mapping - these DLP tv's unable to show 720 lines.
The SD plasmas have 480 lines resolution and even if they have HDMI inputs they called HD compatible.
HD plasmas with 1024x768 are HD Ready because in rules it is not mentioning the horisontal resolution. only vertical.
My Sagem crops 4 pixels from top and bottom and the rest is 1:1.
Another point is - will we notice it? NO. with PC on screen yes, we see it but with TV we will not notice it. :hiya:

I agree - this was my point originally - you won't notice the difference when watching HDTV :)

I've seen 720p and 1080i HD feeds the Samsung and regardless of whether the imae is 1:1 or not it was gobsmackingly impressive. I'd be more than happy to settle for what I've seen so far.

Having said that It would just be nice for them to address the issue non the less - I'd like my cake and eat it :D
 
KableMan said:
Its not the overscan that's the problem its the lack of 1:1 pixel - without the tweaks.
For me at least, both the overscan and lack of 1:1 pixels are a problem. The HD-Ready logo requirements are for the display to use either a fixed vertical pixel count of at least 720 pixels (RGB triplets), or at least 720 active vertical scanning lines. Note the word "active".

The Samsung DLP TVs, with their large overscan at 50hz, clearly do NOT have 720 active lines. I bought an HD-Ready TV expecting a vertical resolution of 720 pixels, with 1:1 pixel mapping when displaying a 1280x720 source. I feel like I've been conned by the whole HD-Ready logo scheme, which supposedly guarantees that a TV meets certain minimum requirements, when it obviously doesn't meet those requirements.

If these TVs can achieve this at 60hz, then why not at 50hz? How can they pass the HD-Ready logo testing criteria?

I take your point about not being able to see any difference when viewing video, but as I've also stated, I definately can see a difference when viewing photographs. Text on signs, etc. is slightly blurred. And will the Sky+HD service really have overscan? If so, won't viewers with plasma and LCD TVs see this overscan, since many LCDs do provide 1280 horizontal pixels.
 
There's something I don't understand here.
With the Psize button we have the ability to increase or decrease the screen picture and then get rid of any possible overscan or underscan. If we suppose that the input signal is exactly 1280*720 and the DLP matrix exatly 1280*720 pixels (or mirrors whatever it is) why can't we obtain a 1:1 exact matching with the Psize ?
 
Having read this thread a couple of times now - I am still confused

The image on my desktop when connecxting my HCPC is fantastic - in fact it appears chrisper than on my 24" Dell

However what settings should I be using to make sure things are as good as they get
 
Just out of curiosity does this apply to the SP46L6HX as well all this jiggery pokery with PIP etc
 
Jamesy_UK said:
Just out of curiosity does this apply to the SP46L6HX as well all this jiggery pokery with PIP etc
As the first post says - "The following method has been confirmed to give pixel perfect picture via HTPC for SP50L7HX and SP46L6HX. It may well work with others too."
 
doh sorry...., read the thread originally ages ago and just jumped to the end this time ;).
thanks anyhow.
 
any news dlpmaybe from samsung over the pixel perfect issue?
 
is it true that DVI to HDMI can result in overscan that would not otherwise be present
 
A quick update. Having chased up Samsung by email, I've been told that this is still being investigated by the Samsung Technical Team. Has anyone else (dlpmaybe?) heard back from Samsung on this?
 
Hi,

They call me almost weekly to tell me that the issue is still being looked into by the "senior technical team". It is starting to get annoying now. It has been a while...
 
DuncanWardle said:
is it true that DVI to HDMI can result in overscan that would not otherwise be present

to kind of answer my own question, I happened to be speaking to a guy the other day who works for Sony on various projects (although not TVs and the like) and happened to mention my new TV

turns out he owns two of the exact same sets (although one is at his parents and I guess is theres now more than his) and he mentioned the overscan thing

anyway - he also seems to think that overscan can at times be caused when using DVI to HDMI cables or convertors and although not doing this on his Samsung stated on his previous set with a Denon DVD player which was connected via DVI to HDMI it resulted in the same thing - however when he replaced the DVD player that was HDMI to HDMI no such problem existed

just wandered if anyone else knew anthing on this - I may try hunting out a VGA cable and see what results I get with that
 
Well I have not got a VGA cable around to try - has anyone tried VGA connection instead of DVI to HDMI and if so whats the quality like ?
 
I got my Samsung SP50L7HX last week and have been having some resolution issues with my PC (ATI Radeon 9800 Pro).
I haven't got a DVI-HDMI cable so have been using a VGA cable for now.
I tried playing with powerstrip and custom resolutions but with no particular success.
If i set the resolution on the PC to 1280x720 (apparently the max res the TV can handle) the TV shows a blue screen and a resolution out of range message :nono:
Setting the resolution on the PC to 1024x768 gives a screen which gives a picture which is resizable via TV remote, but is obviously not of the correct aspect ratio (horizontally stretched to fit screen, as u would've expected)

But for some reason if you set the resolution on the PC to 1280x768 a picture can be displayed by the TV and their aren't black bars whatsoever it fits the screen perfectly :thumbsup: Even though i feared there may be a vertical squash to fit the screen, i really couldn't notice it, although i will look at it closer.
I then decided to see what games would look like on it at this resolution;
Halflife 2 was my first choice, as it is the only game i have which supports widescreen resolutions, but on launch of the menu (yes just the menu) i get a blue screen with out of range :mad:
Upon trying other games at 1280x768 (Battlefield 2 & Farcry set to 1024x768 in game options) i get amazing pictures and they definately do not look like they've been stretched by 200 odd pixels horizontally.

I'm confused;
1) Why does it display 1280x768 and not 1280x720?
2) Why 1280 x768 and not 1366 x768?
3) Why does 1280x768 look so good on a 1280x720 max screen?

I'm quite happy using it like this but I just want to get the best out of my new screen.

My screen at 1280x768

Also, I know this may be a bit off topic, but what will happen when I get my Xbox 360 and it trys to display a 720p picture. I'm hoping this issue is restricted to just PC inputs; well actually i really don't want to have to put up with this issue at all with an "HD-Ready" set.
 
Im not sure but think there may be bit of a problem with ATI cards - I had one and the TV would not excpet 1080 from it and at times would not except 720 from it

Swapped the card for a 6600GT and now it excepts all resolutions I send to it (including 1080)

It may be you have answered by question about what happens when you connect via VGA instead of DVI > HDMI

I was hoping it would be the same without the overscan but seems that its worse

Anyone else have experiance of VGA connection
 
DuncanWardle said:
Im not sure but think there may be bit of a problem with ATI cards - I had one and the TV would not excpet 1080 from it and at times would not except 720 from it

I know my 9700pro had a problem when i sent a 1080i signal to it, the screen would just go black. However my new pc with a x800xl pci-e card works fine at any resolution. Could be older ATI cards / software. The new cards should be fine
 
DLPMaybe said:
They call me almost weekly to tell me that the issue is still being looked into by the "senior technical team". It is starting to get annoying now. It has been a while...
Yes, it's been nearly 2 months since I reported this fault to Samsung. Very annoying, I notice the problem all the time now when viewing my photos, so have to switch to 60hz, and go through the PIP trick. Of course, using 60hz probably isn't going to work with a Sky+HD box is it :mad:

In the meantime, I've been doing some more testing, in the hope of finding some way of displaying a 50hz signal over HDMI with 1:1 pixel match, but without any success.

One thing that's become obvious to me though is that the Samsung DLP TVs are optimised for the American market, and have NOT been properly configured for the UK 50hz market.

For example, look at overscan with a 1280x720 signal. At 60hz, with 1:1 pixel match, total picture area is 1239x694, which is 93% of the picture. At 50hz, total picture area is 1200x673, which is only 87% of the picture. So, when I plug my Sky+HD box into this TV, I'm going to lose 80 pixels across and 47 pixels down. That's an enormous amount of overscan, and even then, that's without any 1:1 pixel mapping.

Secondly, take the PC mode. At 60hz, changing the input name to PC switches the TV into a different display mode. Do this with a 50hz signal, and nothing changes.

Also, at 60hz, you can adjust the 16:9 setting to adjust the amount of overscan, whereas at 50hz there are no additional options for the 16:9 setting.

This suggests to me that Samsung are maybe struggling to make their DLP TVs work properly with a 50hz signal. I'm really surprised that none of the magazines that have tested these sets have noticed this problem.

And how a TV that can only display 673 lines of a 1280x720@50hz picture can be passed as "HD-Ready" amazes me.
 

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