Black frame on Intel config + HDMI display recognized as TV

[MichalCzechScaling]

Hi,

first of all thanks for your work a ahead for reaction.

I am kinda desperate of using. I spend over 10 hours through 3 days trying allmost everything I thought is possible to get that working but for some reason it s not. Basically if i follow guide or YouTube video it s not working as it should. I ll try to be more specific.

1. In YouTube video after mirroring the dummy there is scaling option in dummy monitor in preferences (not by list of resolutions but through "pictures" as on Retina display, that allows desired scaling. In my case it s not. (as seen on attached screenshot)
2. If I somehow through various combination of clicking make a situation where I can see in system preferences that input signal is higher res than actual "seems like". The picture on my monitor (HP 24mq QHD) is smaller than monitor. Like there is sharp image but around is like 5cm black stripe. If I turn on OVERSCAN it s spread to full monitor but it s obviously blurry. (as seen on attached screenshot)
3. If i click to dummy monitor in system preferences it offers mi only few options that are lower than actual monitor. IE my monitor is QHD 2560x1440 but top offered resolution is 2272x1278.
   If I click to SHOW ALL RESOLUTIONS I can choose whatever. But I tried to select even Retina 4K resolution and still nothing.
4. If I make it work, even with problems mentioned in 1. etc ... if I m setting some uncommon resolutions it s working (but badly as I wrote). But if I set some "common" resolution like 1920x1080 (HD), in system preferences it automatically switchs that now dummy is mirroring my HP24mq.

Thaaaaaaanks a lot for any advices or tips. If like a call, chat or remote desktop would be possible, even for money I would be very glad. Cause it s a huge issue for me. I even bought new monitor and now I m thinking of buying 4K monitor or displayport connector or whatever. But before I buy another possible useless stuff I m trying to contact you. Thanks once more. :D

[waydabber]

Hmm. Is there a youtube video? It certainly wasn't done by me. :) Can you send me a link so I can see the steps?

I'd need a bit more info on your config (mac model). Some Intel Macs with AMD Radeon produces letterboxed images when mirroring a dummy.

An other issue might be (especially if you see things like "Overscan" in the mac display preferences)is that your display is erroneously recognized as a TV and will probably have a wrong base resolution when doing mirroring resulting in all kind of weird letterboxed or blurry results. These issues are usually due to erroneous EDID (this is an information store that describes the display's characteristics to the OS) in the display firmware. Usually using a non-HDMI port helps with this issue (if the display offers one).

[waydabber]

Also, please check this post #146 (comment) as there are tools for Intel that might help overcoming this problem.