HDMI input through USB C?

Question

I am trying to connect the HDMI of another device to my computer, but of course the graphic cards don't support HDMI input, so connecting HDMI to HDMI is out of the question.

Since USB-C to HDMI adapters are sold, is it possible to make USB C on my computer as an HDMI in port? (as USB-C is capable of transferring data both ways), and if so how can I do that?

To bring an example, lets say connect a gaming console HDMI port to my computer (like a Xbox or PS), and see it on my screen.

To sum it up, from the original device there would be HDMI, and the input that goes in on my device is USB-C

Or another alternative that would work for me is if it is possible to mirror the screen by connecting a USB C to USB C together.

Solution 1

I am trying to connect the HDMI of another device to my computer, but of course the graphic cards don't support HDMI input, so connecting HDMI to HDMI is out of the question.

Correct. You either need:

1. A device with graphics input (HDMI/DVI/DP/... in, possibly with an additional convertor).
2. Or something which captures the input. Usually to a file or to a window of the capture program. If you maximize this then you are close to your goal.

Since USB-C to HDMI adapters are sold, is it possible to make USB C on my computer as an HDMI in port? (as USB-C is capable of transferring data both ways), and if so how can I do that?

No. First of all those adaptors are HDMI output. They work the wrong way around.

Secondly, USB-C does not carry video. USB-C is the physical form or a connector usually used for two things:

• USB 3.1 gen 2, or
• Thunderbolt 3.

Note that thunderbolt signals can be muxed with displayport video data. There are example where a TB port (with USB-C form factor) is used to attach a monitor. However you best consider it a graphics out with in an alternative connector.

Also note that most (all current?) TB3 connectors use an Intel chipset which can do both TB and/or USB on the same plug. in USB mode it does nothing special with graphics.

To bring an example, lets say connect a gaming console HDMI port to my computer (like a Xbox or PS), and see it on my screen. To sum it up, from the original device there would be HDMI, and the input that goes in on my device is USB-C

For that specific case you need a framegrabber/digitizer with HDMI input and with an USB-C connector to communicate with the computer. And I intentionally write 'communicate' rather than 'steam video in a regular format'.

Or another alternative that would work for me is if it is possible to mirror the screen by connecting a USB C to USB C together.

This would do nothing. And unless USB changed the master-slave setup it can not even work.

Solution 2

Just to make certain I understand your question based on OP and the comments: You want your laptop display to act as a screen for an external video source, and the video connectors on your laptop are not capable of input.

If this is not the case, please clarify your question by editing it.

If the external graphics source is another laptop, there are programs that allow this function: Can I use my laptop as a second monitor?

If the external source is anything else, the answer is "no".

The ports on the laptop are only one part of the equation. The other part is that there is not a direct connection from the ports on your laptop to the screen on your laptop, and so any signal coming in through ANY of the ports must go through processing of some sort in order to be displayed on the laptop's screen. There is software and hardware that can do this (video capture), but it is unlikely to meet your needs.

Specifically regarding Remote Desktop, these are typically very optimized protocols and systems that usually do at least some of the processing of the graphical output on the client computer, allowing for near-realtime display of the remote screen contents.

I would recommend you look into video capture, and specifically capturing video for immediate display or playback. These will still not be realtime, but they may get close enough for certain use.

Comments

[Kinnectus]

I think, either way, you're going to be looking for "USB video capture card" - whether there are many "USB-C" cards available just yet is going to need you to research.

[Ravindra Bawane]

Yes, there are USB-C devices that output HDMI. This is a shopping request question though.

[Kirill2485]

@music2myear No there is not. All those "capture cards" have a delay of around half a second which makes even Remote Desktop over LAN a more viable option then using capture cards.

[Ravindra Bawane]

Laptops are generally not capable of serving their internal displays as usable screens for high speed graphics from a different source. I'm pretty sure that question had been asked before, but I'd have to search to find it.

[Kirill2485]

@music2myear Again, thats only with USB 3.0, not USB-C. Have you heard of a device called the Razer Graphics Amplifier? It works with ANY laptop that has a USB-C port.

[Kirill2485]

@music2myear By your statement you cant play movies in full HD from a flash drive because they need time to render it to the screen from the USB drive

[Ravindra Bawane]

In the context of THIS discussion, "different source" means a different system such as a game console, media player, or any source of video content external to the laptop. That is what you're asking, correct? If not, please clarify your question. You have specifically mentioned Xbox or PS as a source, but you mention also USB-C to USB-C connections, and neither of these devices have USB-C connectors or are capable of sending their video out over the USB connectors they do have.

[Ravindra Bawane]

Further, USB-C and USB-3 will have very similar capabilities as USB-C is simply the compact connector type for the USB 3.1 standard. You cannot differentiate between them because they are the same. The Razer Graphics Amp is a discrete GPU that connects via USB. There are many such devices and I have worked with a few of them. DisplayLink licenses similar products as docks for small computers such as tablets. I don't see how it is relevant to this question or to my comments.

[neuhaus]

The Lukilink Kickstarter campaign wants to build such a device. It's mostly targeted for mobile devices. I suppose adding support for PCs would be "only" a software issue.

[Ravindra Bawane]

I'm voting to close this question as off-topic because it is about an illegal computer system, running MacOS on non-Apple hardware. OP deliberately left this information out of their question and comments because they knew it was illegal.

[Kirill2485]

Also, HDMI doesn't support 4k@60hz, while USB-C does. So USB-C is the superior display cable over HDMI.

[Kirill2485]

All those "second monitor" programs do it over LAN, which is limited to 1gigabit due to Ethernet capabilities. On the otherhand, HDMI is 24gbps, while USB-C is 100gbps

[Kirill2485]

It would do nothing, that is correct, because of drivers. Wouldn't capturing RAW USB C data on the client device be able to capture the information to build a picture? Using wiki.wireshark.org/CaptureSetup/USB for example.

[Ravindra Bawane]

Those are the limitations you must deal with, and focusing on the raw specs isn't the correct perspective. How much bandwidth is needed to send a screens' worth of data? The LAN-based technologies are mature and work generally well and widely. The other techs are newer. There are different overheads. And when it comes down to it, your wanting something to exist does not make it exist. With your avaliable connectors you can go capture card or you can go home. That's what it comes down to.

[Kirill2485]

Well HDMI 1.4a is maxed out at 2k display. 4k would have to be rendered at 30fps due to 30hz... so apparently 21gbps isn't enough to render a quality 4k picture, now imagine how much banndwith it would take to render a 1080p picture smoothly, probably around 10gbps, while Ethernet is 1gbps

[Ravindra Bawane]

Which is why video signals are generally sent encoded and compressed. Which is why you are very limited in the possible types of hardware that will meet your needs.

[Ravindra Bawane]

We can't deal with theoretical solutions because they are theories, not yet existing. The USB protocol is fast, but raw speed isn't everything, and there has to be software and hardware to do this, and these do not yet exist outside the forms we have already mentioned to you.

[Kirill2485]

Exactly. HDMI is at 21gbps while USB-C is 100gbps, so "encoding and compressing" the output and sending it through USB-C would be as effective as HDMI, if not more, then HDMI.

[Kirill2485]

Here's a different example: the computer mouse. It was first used over PS/2 ports and Microsoft had no role into making the new standard for mice to become USB. Logitech, with no help from Microsoft, invented the first USB Wheel Mouse. Before this it was not possible to use a PS/2 to USB adapter to capture mouse movements. But after a few years they also came out with PS/2 - USB adapters.

[Kirill2485]

I also got it to work on a hackintosh thanks to Reddit but I want it to work on Windows, but this is evidence that its possible and its 100% software based. support.apple.com/en-us/HT204592

[Ravindra Bawane]

I'm sorry. You're really being evasive here. We have given you the necessary information regarding the equipment you can use given your setup. I am not interested in theorizing because that is not what we're doing here. In your dreaming you should have spent the money to purchase a computer that accomplishes your needs beyond the limits you are currently working within. If you do not yet have an answer please respond clearly and concretely regarding what else you need. Otherwise, please mark this or the other as the required answer.

[Kirill2485]

The reason I am being evasive is because I know it is a software based issue, not hardware, because I actually got it to work on Hackintosh, but I need it to work on Windows. Basically, I need these drivers installed on my Windows computer so I can view another computer connected via USB-C. Right now the only way to get it on the Windows machine was to create a VMware machine and put OSX on it, but the problem with that is that it hogs up too much resources and the emulation isn't that great... but this just comes to show that its software based

[Ravindra Bawane]

You still don't get it. The reason that works is because Apple designed the iMac to be able to do that. It is a combination of hardware that you don't see and software that you do. We've been telling you basically that exact thing for the past day. There is nothing similar built-in to Windows by default, and a computer manufacturer would have to explicitly design their computer to function in that way and would have to offer drivers that performed that function.

[Ravindra Bawane]

But, because you've been coy and cagey, we've spent time and effort getting you answers and you have withheld information and you have not been satisfied. This is NOT how to ask questions. Give us ALL of the context at the beginning. If you'd shown us that link and said simply "How do I make this work on a Wintel laptop" at the very beginning we wouldn't have spent the last day playing the game we did.

[Kirill2485]

you don't get it. I actually GOT it to work on Windows, by installing OSX on Windows and OSX saw the USBC port. That's what "Hackintosh" means

[chx]

Note: USB 3.1 Gen 2 is 10gbps not 100gbps. That's what USB C has.

[Mr. Goferito]

@Kirill2485 did you manage to get this working? Do you know if it's possible to get the same setup for Linux?