HDMI vs DVI?

Jack Bauer · 24 May 2006 at 20:43

Bear with me, I might not explain this very well

Ive been looking at HD LCD TVs. They come with a HDMI input and a DVI.

However if I plug my cpu into the DVI port the TV has a max res of eg 1300 ish.
If I use the HDMI I can do 1080i, which has a res of 1920x1080

am I understanding this right? Is this the only differnce of using a DVI input?

Fr0dders · 24 May 2006 at 21:56

Jack Bauer said:
However if I plug my cpu into the DVI port the TV has a max res of eg 1300 ish.
If I use the HDMI I can do 1080i, which has a res of 1920x1080

what are you doing putting your processor anywhere near your TV ?

Jack Bauer · 25 May 2006 at 00:14

Apart from the fact that im speaking hyperthetically, Im looking at buying an LCD tv which will be fine near my CPU

McDaniel · 25 May 2006 at 01:47

i think he was trying to point out the fact the CPU is in the motherboard, and wouldnt plug into any sort of DVI - i think you mean your Graphics Card.

Jack Bauer · 25 May 2006 at 09:10

Realy, I new I was doing something wrong :eek:

Sorry by CPU I was refering to computer, bad habit.

Can any one confirm the above for me or put me right If im not understanding it

utherpendragon · 25 May 2006 at 12:15

DVI inputs often have a bandwidth limit on it, by lowering the refresh rate it should go slightly higher. Also to reach any higher you will need a dual link DVI port on your motherboard/graphics card, HDMI doesn't have this problem as bandwidth is speced very high.

Jack Bauer · 25 May 2006 at 12:24

My cards a x1800xt so I have both 2xDVIs and a HDMI. Its more the TV thats my problem. Some say they are HDTVs but dont have a HDMI input. Can I still do 1080i (or P which ever it is) if it only has a DVI input?
Also they state a max res of 1330 ( something like that) however they say they can do 1080i but to my understanding this is 1920 res. Im just a little confused

utherpendragon · 25 May 2006 at 15:21

what is the tv's native res? Thjere's a difference between native resolution and what it can accept. I very much doubt you have a 1920x1080 panel so the input will be scaled down.

Jack Bauer · 25 May 2006 at 19:59

I dont have an LCD TV at all, Im trying to understand what im buying before I get it. If you look up the spec of HDTV it has a 1920x1080 res. Therefore any TV rated as 1080i can do a res of 1920x1080. My question is can I do 1080i thought a DVI input or do I have to use a HDMI input?

Baddass · 25 May 2006 at 22:48

HD signals are typically either 720p or 1080i. 720p referes to a 'progressive' image which is 1280 pixels on 720 vertical lines. These are often referred to as 720 lines and so you need a screen which has a native resolution of at least 1280 x 720 to show 720p HD content. 1080i involves two 'interlaced' halves of the image at a resolution of 1920 x 1080 (hence the 1080i = 1080 lines).

the native resolution of the LCD/ Plasma TV is still 1366 x 768 or whatever it might be. However, it can accept a 1080i HD input but will scale this down internally to a resolution it can handle. This does give a better picture though, but a 1366 x 768 can really only truly operate at 720p HD level as it only supports 720 lines not the full 1080i. You would need a larger TV to display a true 1080i image, and obviously you'd need a 1080i broadcast instead of a 720p broadcast. A lot of Sky's HD is going ot be 720p for instance, and any more would be pretty much wasted over here in the UK anyway with the TV support we have.

So in answer to your question, you can still send a 1080i HD input over both DVI and HDMI, however, because the native resolution of the TV is still 1366 x 768, it will get scaled down anyway.

THC_SsSsSnake · 25 May 2006 at 23:48

do dedicated tft monitors generally give a better iq than hdlcdtv's when both used for pc gaming?

Jack Bauer · 26 May 2006 at 10:18

cheers baddass

MichaelHo · 26 May 2006 at 11:18

Jack B i have recently bought a HDTV LCD monitor and i would advise you to get HDTV with 1:1 VGA mapping, so u can jus link ** pc via vga which will give excellent quality anyway as its 1:1 mapping with the screen. Therefore u can save the HDMI input for something else e.g. xbox 360, sky HD etc. my lcd screen is running at a pc res of 1360 x 768.

Jack Bauer · 26 May 2006 at 13:43

Not to sure exactly what 1:1 VGA mapping is but I will google it and have a read when I get home. Will this give image quality as good as 1080i. Realy this is my only issue as I intend everything to run though my HTPC ( this is already build, just need the TV to go with it : / ) so inputs to the TV aint too important to me at the expense of image quality.

MichaelHo · 27 May 2006 at 00:10

i think it depends on what resolution your tv will go up to, bigger tvs will have bigger res i think.

Fr0dders · 27 May 2006 at 00:17

1:1 pixel mapping refers to the fact that most PCs will drive a resolution of 1360 x 768 but most LCD tvs have a native resolution of 1366 x 768. That 6 pixel difference can cause a problem. Your TV may force you to stretch the image over the extra pixels, meaning that 1 pixel from your signal, takes up 1.0001 pixels on screen bluring the image

this is very much the same effect you get if you run your monitor outside of its "native resolution"

with 1:1 pixel mapping the extra 6 pixels just remain black, ensuring that 1 pixel from your monitor signal is 1 pixel on screen.

THC_SsSsSnake · 27 May 2006 at 16:12

Mr Lol very interesting, where in leicester?