Picture quality with HD
#1
Hi,

I'm in the process of buying a HDTV (42") and one of the reasons for having it is picture viewing. I will be looking for a set that supports 1080p through HDMI and VGA to connect my laptop to, but I also have a modded XboX running XBMC. I am wondering what to expect from xbox. I now it supports 1080i from component output (and is limited by only 64MB of available RAM) but what is the quality of this mode? How good do pictures really look at 1080i? Big Grin
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#2
forget about 1080i output of the xbox. it's just to slow and has too little memory. 720p is all you can hope for and looks alot better than SD DVD's anyway.

make sure that the TV supports 1080p24/30 for smooth playback of HD-DVD and Blu-ray (and future XBMC on Linux?).
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#3
I've read that the Connextant video processer on the Xbox can actually only take an input at a maximum of 1024x768, but can output at 720p and 1080i but since the input is at a lower resolution you're not getting 'true' 720p. Though I imagine the 1028x768 image going in is anamorphic and makes fairly efficent use of the available resolution.

Though you're still effectively only getting 85% of the detail at 720p than you would get at 'true' 720p resolution.
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#4
DJ_Izumi Wrote:I've read that the Connextant video processer on the Xbox can actually only take an input at a maximum of 1024x768, but can output at 720p and 1080i but since the input is at a lower resolution you're not getting 'true' 720p
That is wrong (a lie). The Xbox hardware on the other hand is not powerfull enough to playback native 720p/1080i/1080p video resolutions, it can however display true 1920x1080 resolution pictures in true 1080i.
http://xboxmediacenter.com/wiki/index.ph...V_media.3F
http://xboxmediacenter.com/wiki/index.ph...esolutions

720p output is recommended instead of 1080i on the Xbox because of the memory limitation (64MB shared)
http://xboxmediacenter.com/wiki/index.ph...an_I_do.3F
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#5
Gamester17 Wrote:That is wrong (a lie).

Hmm, in further reading calling it a 'lie' is a bit harsh. Reading the datasheet for the IC, while the maximum of 1024x768 into the chip is stated, it later specifies that 'nonstandard' resolutions are possible within certian threasholds and it includes HDTV resolutions with that.
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#6
DJ_Izumi Wrote:Hmm, in further reading calling it a 'lie' is a bit harsh. Reading the datasheet for the IC, while the maximum of 1024x768 into the chip is stated, it later specifies that 'nonstandard' resolutions are possible within certian threasholds and it includes HDTV resolutions with that.

Yeah I thought that was a bit mean, lol. I doubt he had some malicious intention or something Big Grin
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#7
Hi,

after a while, I settled for a 46" Sony Bravia and XBMC looks great Big Grin. There are some problems though. I use 1080i and for some reason, pictures are cropped when viewed in slideshow mode, even with "Pan and Zoom Effects" option disabled. See here, there is no zoom active.

"Normal" view:
Image

"Slideshow" view:
Image

Tested with latest (2008-01-13) T3CH, I've just upgraded just to be sure. Another thing...with the latest version, "normal" view switches to the next picture after a short while, then repeats (really repeats it...it fades out, then fades in with the same one) that picture for a while. I though normal view should stay on one picture unless 'next' is pressed?
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#8
@gulikoza:
I had the same problem. You need to change the parameters with advancedsettings.xml.

The concerned fields are:
<slideshow>
<panamount>
<zoomamount>
<blackbarcompensation>
</slideshow>

I don't remember which values need to be set. But the wiki and some tests should allow you to solve this.

Regards,

Eric
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#9
I think you just need to set <blackbarcompensation> to "0" but I'm not sure.
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#10
Yes, it's <blackbarcompensation>. Thanks a lot!
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#11
@gulikoza:
Make sure you setup that beast of a TV correctly. It made a massive difference to my 40" (from the standard picture) when I followed the settings on avforums (http://www.avforums.com/forums/forumdisplay.php?f=155)
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#12
I set my XBMC to 1080i and use the Hardware Overlay option in the video settings.

That produce fluid playback at 1080i with no frame drops. The only downside is that I do get a bit of flickering in a horizontal band along the top of the screen from time to time. But I honestly don't even notice it after a while.

For any video that isn't already widescreen I just change to 14:9 using the Enter button on the remote. That seems to reproduce the best looking widescreen playback. 16:9 seems to stretch things a little to much for my taste.
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Picture quality with HD0