output quality from xbox conexant pal

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vinnieb
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Joined: Mon Nov 29, 2004 10:12 am

output quality from xbox conexant pal

Post by vinnieb »

Hi,

Just a question to see if my understanding of the output limitations on the xbox are right! I've read through any and all faqs and threads on this, but there seems a degree of conflict between peoples opinions.

Basically, I've got what I believe to be a 1.3 xbox running Gentoox. I'm using a VGA monitor with this via an XGA converter kit, and as I'm sure you've all guessed, the output quality isn't very impressive!

So, what can be done to improve this? I gather than MS has kindly limited the output quality by disabling a few sync signals on the o/p so that whilst it looks ok on tv or projector, it looks poor on a VGA setup. It also seems that people with US/NTSC versions of the box don't have this trouble as the sync signals are still there and with the X2VGA kit they kit crystal output.

I've noticed that if I use vnc to the box then I get a crystal clear picture, so clearly the internal signals are all fine, its just massacred at the o/p stage, or my VGA/XGA converter setup is wrong/poor. I've seen a couple of HOWTO's about this, some even go so far as to guide how to do some internal soldering to the board to access the sync signals. I'm not too keen to have to do this, but if its the only way...

I've played around with resolution and timings settings, but none of that makes any difference, as I guess what I've read about the output stage being reduced in quality is true..

So, any suggestions? I looked at a piece of software that was said to convert the box from PAL to NTSC but I don't see how this can improve things if there is a physical cut down in quality, though I suppose it could be software controlled.

Thanks for any ideas.
nobspangle
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Location: Manchester, UK

Post by nobspangle »

Basically standard TV is crap quality so you don't get a good output there. Standard video-vga convertors are just using this crap tv signal and extracting the sync information and the relaying it in a format understood by a vga monitor.

The xbox is also capable of outputting HDTV (only in NTSC mode) HDTV unlike normal TV is very high quality and is progressive (lines drawn one in numeric order) as opposed to interlaced (odd and even lines drawn seperatley). The X2VGA uses this high quality signal and converts it for replay on a VGA monitor.

To sum up,
standard convertor crap in = crap out
X2VGA quality in = quality out
If you keep an open mind, will your brain fall out?
vinnieb
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Post by vinnieb »

Sorry for my slow response..

So does this mean that there is a method for getting a standard UK xbox and get it to switch to NTSC mode and thus output an HDTV signal? The converter box i'm using can handle HDTV signals I gather, and even if not then it's worth a try. I'd seen some patch that would modify the xbox dashboard to NTSC mode from PAL but this wasn't much use for me as I'm not interested in using the xbox for games. Is it possible to make this change for the gentoox loader or something along those lines?

thanks.
nobspangle
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Location: Manchester, UK

Post by nobspangle »

I'm not too up on this I've never seen an HDTV someone else who has a PAL xbox and an X2VGA will know.
If you keep an open mind, will your brain fall out?
nangsyde
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Post by nangsyde »

I think this can be done with an app called the Enigmah Video Mode Select CD. You'll have to go through the usual scum pits to get it, but it should run ok and let you access the hdtv modes on a PAL xbox.
dmp
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Joined: Sat Oct 23, 2004 5:00 pm

X2VGA

Post by dmp »

The limitation on the X2VGA is purely done in the MS bios/kernel.

Linux can output HDTV modes via an X2VGA converter, whether it is a PAL or NTSC xbox. There is no need to 'switch' the eeprom to one mode or the other.

Just plug it in, and follow the normal GentooX menus to select X2VGA as the output device.

Remember, both PAL and NTSC xboxes are physically identical - it is just the setting in the EEPROM which distinguishes them. So there is no reason (other than MS disabling it in their bios) that you cannot get X2VGA to work with a PAL xbox.

David
vinnieb
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Joined: Mon Nov 29, 2004 10:12 am

Post by vinnieb »

I thought the x2vga only worked with the US NTSC versions of the xbox, i seem to remember having read that from their website. Though I guess if the bootloader could select this mode from what people have said.

Has anyone had success with a standard UK PAL xbox and the x2vga kit and actually got a decent output on a VGA monitor? At the moment mine is very fuzzy, possibly due to the poor VGA converter box! It is running in 480p HDTV as selected from xbvset but maybe the converter isn't doing a good job at handling that, as it looks exactly the same regardless of what settings I choose. Oh, unless i try the 720p which results in a blank screen at bootup, no bootloader options and a frozen xbox
dmp
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Post by dmp »

As I said, the only difference between the US xbox and the PAL xbox is the eeprom setting.

The MS bios CHOOSES to disable HDTV output if the xbox is set to PAL mode.

However, Linux will happily display HDTV output regardless of what the PAL/NTSC setting is.

The bootloader does not 'set' anything, it's simply that the video driver is happy to display HDTV in both pal and ntsc modes.

I have a UK PAL Xbox and an X2VGA, and things work swimmingly in 480p. If you have one of the cheap and nasty VGA boxes that do not manifest themselves as an HDTV cable, you will get low quality output.

If you want to find out what it identifies as:

dmesg | grep xbox

and you'll see what the video driver says at bootup.

David
vinnieb
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Joined: Mon Nov 29, 2004 10:12 am

Post by vinnieb »

Ahhh I see. I wondered where the PAL/NTSC limitation came in, i'd be thinking that the signals were disabled at a hardware level. I checked out the dmesg report,

xboxfb: Setting TV mode from EEPROM (PAL-PDGHI)
xboxfb: detected Conexant encoder
xboxfb: setting cable type from AVIP ID: Composite

which I guess are the most relevant ones. I guess the 3rd line is different if you use the x2vga, currently I'm using the standard composite cable going into the vga adapter (probably hence the poor quality output!)

Glad to know the x2vga does work with the UK pal xbox, looks like i'll be buying one of those, hopefully my eyesight will recover from the effects of my current converter!!

Thanks for the info.
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