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Output 1080i via VGA cable?

ben12345

Active Member
I'm looking for a way to trick the console into outputting a 1080i (like when using the component/HDTV cable) through the VGA cable.

My projector will do 720p (1280×720 through the VGA cable), but is at its happiest at 1080i. Its an old projector and doesn't have component inputs, hence looking for a workaround.

I was thinking that bridging the ID1-1.1 and ID3-3.1 in the AV plug might do the trick, like it does when enabling the scart RGB mode, but I haven't tried it yet.

Cheers,
Ben
 

Munkey Boy

Distinguished Member
I was of the understanding that VGA is inherently progressive, so I'd guess interlaced is out. The 360 can output 1920x1080 via (ie. 1080p), but if your projector can't take that, I'm not sure what you can do.
 

ben12345

Active Member
VGA or RGBHV as it should technically be called in this instance can do interlaced or progressive. I'm feeding my display 1080i at the moment from SkyHD through an HD Fury. I'd do the same with my xbox, but I have the old fasioned none HDMI version, hence i'm looking for a workaround.

I remember back in the olden days, you could solder an internal jumper in the PS2's to force RGBS output instead of component.
 

shagaboopon

Well-known Member
VGA or RGBHV as it should technically be called in this instance can do interlaced or progressive. I'm feeding my display 1080i at the moment from SkyHD through an HD Fury. I'd do the same with my xbox, but I have the old fasioned none HDMI version, hence i'm looking for a workaround.

I remember back in the olden days, you could solder an internal jumper in the PS2's to force RGBS output instead of component.

I'm pretty sure the 360 VGA output is progressive only too.
 

bonzobanana

Well-known Member
Which projector is it? You can set the 360 to the native resolution of your projector for the best results. The 360 can do the following;

* 640 x 480
* 848 x 480
* 1024 x 768
* 1280 x 720 (equivalent to 720p)
* 1280 x 768
* 1280 x 1024
* 1360 x 768
* 1920 x 1080

Plus you can choose the aspect 4:3 or 16:9 to match your projector.
 

ben12345

Active Member
Its an old CRT projector... Barco Data 800, about 1992 vintage I believe, so it works better in interlaced mode.
It will do progressive, but the image is quite soft. I've been using it at 1280x768, but I was hoping I could get the HDTV video modes up and use 1080i.
 

CAS FAN

Distinguished Member
I'm afraid that you will be stuck with the 720p output if your projector does not accept 1920 x 1080. I don't suppose that there's such a device that can interlace a progressive signal on the fly (i.e. turn 1080p into 1080i)? I've not heard of one, but you never know.

VGA has always worked by outputting a set resolution (i.e. a progressive signal) as computer monitors have always accepted that type of signal. That is simply due to the fact that they are not designed to have to receive a broadcast signal (which has had to be interlaced due to bandwidth issues in broadcasting the signal - such as a TV broadcast for example) so adding an interlacing stage has not been required.
 

GMC79

Distinguished Member
God i remember that old projector after looking it up, Does look pretty old (1990 it is). and was said to cost almost $20000 new and a max screen size of 20 feet :eek:

What i was gonna say is u realise the max res of that projector is stated as 1024x768p ?, so if that's true setting it higher on the 360 not gonna make much difference tho it will support selecting 720p and 1080i it wont be true 720p or 1080i. (bit like me selecting 1080i on my 360, just scaled down again for my TV and dont look as good) Prob be best selecting 1024x768 as it's it's native res and trying progressive with that, the scaling may have made it soft looking at the other res's u tried with progressive.
 
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ben12345

Active Member
VGA has always worked by outputting a set resolution (i.e. a progressive signal) as computer monitors have always accepted that type of signal. That is simply due to the fact that they are not designed to have to receive a broadcast signal (which has had to be interlaced due to bandwidth issues in broadcasting the signal - such as a TV broadcast for example) so adding an interlacing stage has not been required.

I'm sorry, but i'm going to have to disagree
Back in the olden days before LCD monitors were the norm, it was quite common for the smaller and cheaper 'Super VGA' monitors to only support a true 800x600 progressive signal, but also 1024x768 interlaced. Even the high end monitors used interlacing to get very high resolutions, simply because the electronics in the display couldn't support the bandwidth needed for a progressive signal.
I believe utilities such as Powerstrip still today offer the adjustment of enabling interlaced output on modern graphics cards, but I don't know how LCD monitors would react... It would probably still work, but it won't look great, because they are designed for 1:1 pixel mapping. Like trying 800x600 on an LCD designed for 1280x1024.

These old CRT projectors work differently to the modern LCD/DLP projectors. They are more like old CRT computer monitors.
They dont have to scale the image to fit the number of pixels in the screen, because the number of pixels is pretty much variable from 480i upto whatever I can squeeze out of it. The number of scan lines on the tubes is variable, matching whatever the input signal calls for.

I do realise that Curt Palme's website quotes the max resolution as 1024x768 progressive, but I find that information misleading... I have had 1440x900p and I think a little more too when I had a PC connected to it.

Like I said, I currently display Sky HD at 1080i, and it displays 720p from Sky too, but the interlaced image suits my projector better.

I'm sure i'm not the only person wanting the HDTV settings available when using the 'VGA' cable, so I'll have to do a google to see if there is a hack.
 

CAS FAN

Distinguished Member
I'm sorry, but i'm going to have to disagree
Back in the olden days before LCD monitors were the norm, it was quite common for the smaller and cheaper 'Super VGA' monitors to only support a true 800x600 progressive signal, but also 1024x768 interlaced. Even the high end monitors used interlacing to get very high resolutions, simply because the electronics in the display couldn't support the bandwidth needed for a progressive signal.
I believe utilities such as Powerstrip still today offer the adjustment of enabling interlaced output on modern graphics cards, but I don't know how LCD monitors would react... It would probably still work, but it won't look great, because they are designed for 1:1 pixel mapping. Like trying 800x600 on an LCD designed for 1280x1024.

Yes apologies, I do remember my old monitor displaying some interlaced signals but they always looked to flickery so I just stuck to the progressive signals.

I don't think that there's ever been much of a bandwidth issue with the VGA cables and the connection method itself, but like you say, older displays (like the one I got with my first PC, a 486) will just not have been capable of high resolution progressive displays.
 

mattclarkie

Distinguished Member
Well the official fan site for the model say 1080i is a go, and as you use it for Sky HD I guess it is. But you wont be getting that via the 360 unless you buy a component to VGA converter, which is an expensive piece of kit.
 

ben12345

Active Member
Yep, that was my conclusion too... so I did buy a component to VGA converter based around the National LMH1251 intergated circuit, which supports all resolutions upto 1080P.
It simply passes through the signal, with no scaling involved.

A little bit of googling and this fine piece of kit was found for £15 delivered!

I was trying to avoid yet another 'black box' in the signal chain to the projector, but it seems like it was unavoidable unless I wanted a progressive resolution, which doesn't look great on my machine.

It will go something like this:

Xbox > Component to VGA box > Sync converter > Video switch > Projector

Sometimes I think it would be easier to get a digital projector, but after I see some LCD/DLP ones in action displaying TV or Movies, it reminds me why I keep the old CRT projector! I think its showing something like 7000 or 8000 hours at the moment, and I've not had any expensive lamps to replace!
 

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