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androne
June 12th, 2010, 05:46 PM
hi

Are there many people here using tvs with max or native resolution of 1920x1080i
I have old cheap tv with 1080i as maximum and native resolution as was wondering what people use for mythfronted gui and video output.

its just the screen flickers too much looking at the gui

androne
June 13th, 2010, 09:59 AM
Maybe I should rephrase, has anyone been successful or know of a way to use the gui at say 1280x720p and have video output at 1080i

when I try this x has to be 1920x1080i but when the mythfrontend starts, in doesnt fill the whole screen and only sits in top left corner of the screen.

thanks

tgm4883
June 13th, 2010, 04:57 PM
Define flickering. The frontend needs to be the same resolution as the system in order to use the full display. What video card are you using? Are you sure your video card support 1980x1020? What tv?

androne
June 13th, 2010, 05:27 PM
Hi thanks for your help

I think the flicker may be defined as interline twitter as Its very similar to the twitter in this diagram http://en.wikipedia.org/wiki/Interlace but i dont know for sure.

Yes x and frontend is at 1920x1080i but due to the flicker i was wondering if i can have mythfrontend at 1280x720p maybe i need to do something with xrandr before starting mythfrontend.

video card is an onboard nvidia 8300 mobo is ASUS M3N78-EM. Video card supports 1920x1080i

TV is elonex lnxf3-37 http://www.ebuyer.com/product/132693

tgm4883
June 13th, 2010, 11:57 PM
That TV you just listed isn't 1920x1080, it is 1366x768. You should set your x resolution to that.

androne
June 14th, 2010, 07:31 PM
im afraid not, maybe in vga but ive not tried. Over dvi it reports the native resolution is 1080i at 60hz but flickers too much for the gui. At 50hz the text overlaps but it doesnt flicker.

I Tried a non-native 1366x768 over dvi and it wouldnt accept signal. It accepts 1360x768 but its not the native resolution.

Don't think there is a nice way to have a gui at 1280x720p and have video output at 1080i

Might just stick to a 720p resolution all round

tgm4883
June 14th, 2010, 10:05 PM
I'm by no means an expert in resolution, but I don't think you understand how resolution works.

nickrout
June 15th, 2010, 02:19 AM
im afraid not, maybe in vga but ive not tried. Over dvi it reports the native resolution is 1080i at 60hz but flickers too much for the gui. At 50hz the text overlaps but it doesnt flicker.

I Tried a non-native 1366x768 over dvi and it wouldnt accept signal. It accepts 1360x768 but its not the native resolution.

X won't accept a resolution that is not a multiple of 8.


Don't think there is a nice way to have a gui at 1280x720p and have video output at 1080i

Might just stick to a 720p resolution all round

alien878
June 15th, 2010, 10:34 AM
im afraid not, maybe in vga but ive not tried. Over dvi it reports the native resolution is 1080i at 60hz but flickers too much for the gui. At 50hz the text overlaps but it doesnt flicker.

I Tried a non-native 1366x768 over dvi and it wouldnt accept signal. It accepts 1360x768 but its not the native resolution.1366x768 is most likely the native resolution on your TV (1360x768 is because your video card expects something divisable by 8 ). Native resolution is how many real pixels are on the panel. Most TVs that advertise 1080i are really 1366x768. Overscan trims some of the pixels, the TV scales the rest.

Which is better depends on which has the better scalers/de-interlacers: The TV or mythtv. It also depends on whether you want overscanning (1080i overscans, 1360x768 generally does not). I can only recommend you try them out and pick the one that looks better.

I use 1360x768 because I hate overscan and even if you output interlaced, mythtv will probably have to deinterlace/interlace internally to process the image. I don't want to deinterlace twice (once in myth, once in the TV).

A good summary of 1366x768 is here:

http://hd1080i.blogspot.com/2006/12/1080i-on-1366x768-resolution-problems.html

androne
June 15th, 2010, 06:05 PM
Ok i understand resolution. I guess the mistake is taking the tv advertising 1080i at 60hz as its native resolution as gospel (as per nvidia-settings menu)

I have another 1366x768 tv which does actually advertise this as its native resolution.

Unfortunately via hdmi (not dvi) mine appears to overscan at 1360x768 but thats fine I can adjust that. When feeding the tv this 1360x768 resolution the tv reports its 1080i at 60hz is that correct?

I was hoping to get it to accept 50hz refresh rate but for this:

http://www.mythtv.org/wiki/User_Manual:JudderFree

you'll see notes at the bottom regarding 1366x768 displays so it doesnt look like this is possible.

LowSky
June 15th, 2010, 09:36 PM
I dont get why you are having such an issue?

My TV resolution when using VGA is 1366x768, when using HDMI I have to use 1280x720. Both lok just fine using MythTV

It has no problem playing 1080i video not matter what and seems to scale the video just fine regardless. Much better than my monitor which has the horrible rez of 1440x900.

alien878
June 16th, 2010, 01:10 PM
When feeding the tv this 1360x768 resolution the tv reports its 1080i at 60hz is that correct?Technically, no. But not surprising :) You might want to double check if the card is outputting interlaced as implied by 1080i. If it is, you might want to try a non-interlaced mode to compare. I find the interlacing settings often have a big impact on picture quality.

I was hoping to get it to accept 50hz refresh rate but for this:

http://www.mythtv.org/wiki/User_Manual:JudderFree

you'll see notes at the bottom regarding 1366x768 displays so it doesnt look like this is possible.Interesting. I'll have to play with this and see if I can see a difference. However, since the original 24fps has judder (something I hate at real theaters), it is arguable that upscaling to 30fps sometimes improves things:

http://www.projectorcentral.com/judder_24p.htm

The only thing you can do is try the different options and pick what looks best.

LowSky: To answer why.... Some TVs have good scalers and de-interlacers and the difference isn't noticeable. Some TVs have terrible scalers and de-interlacers and there is a very noticeable difference with the different resolutions.