onemoretimex :
reason being when set to my 4k tv native resolution there was lag as it couldnt be set to 60hz only 30 hz.
HDMI 1.4 is limited to 4k @ 30 Hz (I hear some implementations are actually 29.97 Hz).
HDMI 2.0 allows 4k @ 60 Hz. So likely your GPU's HDMI output or TV's HDMI input only implements HDMI 1.4.
in the catalyst control centre there is an option to upscale, what exactly does this do when enabled ?
Upscaling is taking an image drawn at a certain resolution, and re-sizing it for a higher resolution. On cheap devices, this will be simple duplication. So for example if you upscaled 1366x768 to 1920x1080, the extra pixels would just be a copy of the adjacent pixel. This results in a lot of jagged lines which look really bad.
Most video players and TVs will resample when the upscale, which smooths out those jagged lines without the expense of redrawing at the higher resolution. Do note that the amount of information in the picture is not increased - there is still only 1366x768 pixels worth of detail in the image. It's just that the "noise" introduced as jaggies by the mis-matching resolution is reduced by a simple smoothing algorithm. In some cases this can be used as a cheap (and quick) form of anti-aliasing.
For 1080p to 4k upscaling, this resampling can create the illusion of higher resolution in diagonal lines, but the actual amount of detail remains the same as the 1080p image. I suspect though that some manufacturers took the easy way out and simply rescale the 1080p image to 4k. Each 1080p pixel maps to four 4k pixels, so there's no smoothing of diagonal lines and it just looks like a 1080p image.
also there is scaling options underscan and overscan what does this do ?
Overscan is enlarging the image so it's larger than your TV screen. That is, the edges of the picture fall outside the screen, and aren't visible. Underscan is the opposite - the image is smaller than your TV screen.
These exist for obscure historical reasons (data like closed captioning used to be encoded at the edges of the image). With a PC hooked up to a TV, you want to set the TV for 1:1 pixel to pixel mapping. Each brand of TV calls this something different - Direct, 1:1, PC, Native, etc.
https://www.engadget.com/2010/05/27/hd-101-overscan-and-why-all-tvs-do-it/
i had it in my head that if i was playing a movie that was in 1080p with Media Player Classic because my tv's native resolution was 4k it would upscale the image when played fullscreen improving on the 1080p somewhat or is this wrong ?
It depends on the media player and TV. A good one should upscale the image to 4k. Or if your PC is set to 1080p the TV should upscale it to 4k. (Or resize instead of upscale, since it's a 2:1 integer multiple.) But with a poor media player or TV, you could end up with a 1080p movie in a small box in the middle of the screen. I would imagine every TV manufacturer foresaw this possibility, and took steps to make sure it never happens and the image is automatically rescaled. But I've seen some stupid behavior from cheap no-name TV brands.
If because of your HDMI interface limitation you're only sending a 1080p image, then the TV's image cannot be any better than 1080p. Your media player could be playing a 4k movie, but it would downscale it to 1080p to transmit it over the HDMI cable. Your TV would then receive the 1080p image, and upscale it to 4k. But you would have lost half the image detail in both axes in the process.
if both are enabled do they automatically upscale all media i watch be it through a media player like media player classic or online through browser netlfix, youtube etc.... and windows 10 apps like netflix youtube etc..
Impossible. If you turned both on, the media player would be trying to send a 1080p image upscaled to 4k @ 30 Hz to the TV. The TV would assume it's a native 4k image and not do any scaling. So only the media player would be scaling.
Given your 4k @ 30 Hz limitation:
■ If you're trying to play back 4k movies shot at 30 Hz, go ahead and send it to the TV at 4k @ 30 Hz. i.e. Set your PC to 4k resolution and live with 30 Hz for the duration of the movie.
■ If you're trying to play back 4k movies shot at 60 Hz, you can try to send it natively and hopefully the GPU will downsample it to 30 Hz (send every other frame).
[*[ Or if you must have 60 Hz you'll have to set your PC's resolution to 1080p, and you'll have to live with the lower resolution.
■ Or figure out which component doesn't support HDMI 2.0 and is limiting you to 4k @ 30 Hz, and replace it. Hopefully it's your video card. If it's your TV, oh well, you're stuck with it. I spent a couple years warning people not to buy 4k TVs for precisely this reason. If it's any consolation, those of us buying 4k TVs today thank you for being an early adopter and feeding R&D money to the TV manufacturers to help them get 4k technology straightened out.
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