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Explaining 4K 60Hz Video Through USB-C Hub

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Re: Explaining 4K 60Hz Video Through USB-C Hub

#31

Post by dheera »

mantoto wrote: post #30
dheera wrote: post #29

Earlier quoted context omitted.

Not only that, but the USB-C plug itself is the worst-designed plug I have seen in a decade. It's flimsy sheet metal on the plug side with a nice big cantilever, and flimsy sheet metal soldered to a PCB on the other. Perfect recipe for broken ports and cables. I break about a cable a week and break a device every now and then. Mostly doing very normal things like charging a phone in my pocket while hiking. USB-C seem…

That's just bullshit. You can check for how many uses a usbc plug was designed and tested for.

Well, they keep breaking on me and (a) DC barrel connectors (b) headphone jacks (c) XT30U (d) BNC (e) DB9 and a bunch of other connectors almost never break on me.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#32

Post by nrclark »

USB-C is a train-wreck for those of us who work in electronics design.

USB-C's chipset support isn't all that good, it seems like. With USB 3 type A, you pretty-much just run your USB lines to the ports on your CPU. Simple, straightforward. Manufacturers are happy to do it, because it's dirt cheap and requires nothing except the connectors and maybe some ESD protection.

USB-C is a different beast entirely. Just to use the USB 3 lanes, you need to put down a high-speed mux just to deal with both connector orientations.

Want to support USB Power delivery (transmitting or receiving)? That'll be another set of chips to put onto the board. Plus software to deal with the PD negotiation.

Want to support Displayport? That'll be _another_ mux chip. Plus more software to advertise the functionality.

The cables are also much harder to manufacture, and this is reflected in their average price after you chop off one or two outliers.

Is your item a USB host? A device? Does it accept or provide power over USB? Does it support Displayport? Thunderbolt? Analog audio? Something else entirely? There's no way to know from looking at the connector. And no standardized markings that I've ever seen.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#33

Post by yaantc »

fulafel wrote: post #10

re "Driver availability and compatibility for Mac/Linux is spotty to non-existent": Is it true that DisplayLink doesn't work well with Linux? Some years ago people were saying that the usb-to-monitor dongles worked well. A casual web search also gives this impression, with good support provided by the DisplayLink company.

You can make Display Link (DL) work with Linux, there are drivers from the vendor and an adaptation script for Debian based distros [1] (and variants for others IIRC). You may have to fiddle with the configuration to avoid issues like minor display corruptions or cursor glitches. I made it work clean once, but in the end I returned the dock. DL is to me a bad idea, except is some specific cases.

The way DL works is that a driver on your PC creates a virtual frame per screen, composed on your PC. Then this screen(s) content is compressed and send to the dock DL chip using a proprietary driver. The chip on the dock reconstructs full images and send that to locally attached screen(s) using local HDMI or DisplayPort interfaces. Now yes, those local interface(s) may run at 60 Hz and be 4k. But the bottleneck is not there, it is in the compression and transmission over the USB link. In my experience, any use-cases with large changing content (e.g.: full screen video) will give a bad experience on a laptop (which is what I used, and is natural with a dock). The compression will ramp up the CPU load on the laptop, the ventilator will get noisy, and the display content was choppy too. It's definitely not the smooth experience you expect from 60 Hz.

I guess DL can provide very good results with a laptop for use-cases with mostly static content: reading documents, spreadsheets, word, etc. Just don't expect to have a nice experience when most of the screen content changes quickly.

So I returned my DL USB-C dock, bought a super cheap one as actually I only have a 1440pt external screen for which any cheap dock will support true 60 Hz, and I have a nice experience. For 60 Hz with 4k it'll have to wait, and it won't be with DL as far as I'm concerned.

[1] https://github.com/AdnanHodzic/displaylink-debian

Re: Explaining 4K 60Hz Video Through USB-C Hub

#34

Post by pm7 »

Nextgrid wrote: post #26

The USB-C spec is an insane mess. The fact that every port used to be different is actually a feature, as it helps you identify which device supports what based on the ports it had. If you see an HDMI port on a laptop you can be sure it's going to output some kind of video signal over that. If you see Thunderbolt then you're sure the machine supports Thunderbolt. USB-C just jams all these incompatible standards into…

I think in future devices are supposed to support as many popular functions as possible. Due to trend of thin devices we need smaller ports and fewer of them. Multiple possible use of same ports helps.

> As a user there is no easy way for me to tell the 12-inch Macbook's USB-C port is different than the Air/Pro unless you explicitly search for it in the tech specs

Seems like manufacturer failure.

> If you see an HDMI port on a laptop you can be sure it's going to output some kind of video signal over that.

But even HDMI/DP have versions. It's especially visible now, as we have >=4k HDR high-frequency displays.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#35

Post by phire »

wavesquid wrote: post #8

The HP ZBook Dock with Thunderbolt 3 tends to be on ebay for around US$50 and should do 4K 60Hz.

Avoid that one. There is a reason why it's so cheap on ebay.

Sure, it's a Thunderbolt 3 dock, but the two displayport ports aren't using thuderbolt 3. The are actually connected via USB displaylink.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#36

Post by BiteCode_dev »

nrclark wrote: post #32

USB-C is a train-wreck for those of us who work in electronics design. USB-C's chipset support isn't all that good, it seems like. With USB 3 type A, you pretty-much just run your USB lines to the ports on your CPU. Simple, straightforward. Manufacturers are happy to do it, because it's dirt cheap and requires nothing except the connectors and maybe some ESD protection. USB-C is a different beast entirely. Just to us…

I'm completely ok with it being complicated to design and cost 10 euros more if it delivers.

And despite all its flaws, USBC does. It's small. It's reversible. I can charge all my devices on it: my samsung tablet, my oneplus phone, my logitech mouse, my jabra headphones, my switch and my XPS 13 laptop, which I can also dock to my screen/ethernet. It's amazing.

So yes, I had to take the time to find the proper cable, and I bought a few before finding brands I can trust to work with all my machines... and not fry them.

It sucks, but it will improve with time, like it did with early USB and HDMI (too many people forgot how terrible THAT was). It already has, in fact, improved a lot, and it will keep it up.

Meanwhile, I have only one cable and one dongle in my bag that do everything. I don't even have to get them out most of the time.

This is imperfect. This needs fixing.

But this is better than what we had before. Way better.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#37

Post by darkwater »

Nextgrid wrote: post #26

The USB-C spec is an insane mess. The fact that every port used to be different is actually a feature, as it helps you identify which device supports what based on the ports it had. If you see an HDMI port on a laptop you can be sure it's going to output some kind of video signal over that. If you see Thunderbolt then you're sure the machine supports Thunderbolt. USB-C just jams all these incompatible standards into…

All the issues you are reporting are just growing pains and will be sorted out/disappear alongside adoption and as the standard matures. USB-C is what a computer connector should have been from day 1.

Edit: spelling

Re: Explaining 4K 60Hz Video Through USB-C Hub

#38

Post by jdc »

nrclark wrote: post #32

USB-C is a train-wreck for those of us who work in electronics design. USB-C's chipset support isn't all that good, it seems like. With USB 3 type A, you pretty-much just run your USB lines to the ports on your CPU. Simple, straightforward. Manufacturers are happy to do it, because it's dirt cheap and requires nothing except the connectors and maybe some ESD protection. USB-C is a different beast entirely. Just to us…

Standardized markings to indicate capabilities would be a big upgrade from the status quo.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#39

Post by blurbleblurble »

dheera wrote: post #29
Nextgrid wrote: post #26

The USB-C spec is an insane mess. The fact that every port used to be different is actually a feature, as it helps you identify which device supports what based on the ports it had. If you see an HDMI port on a laptop you can be sure it's going to output some kind of video signal over that. If you see Thunderbolt then you're sure the machine supports Thunderbolt. USB-C just jams all these incompatible standards into…

Not only that, but the USB-C plug itself is the worst-designed plug I have seen in a decade. It's flimsy sheet metal on the plug side with a nice big cantilever, and flimsy sheet metal soldered to a PCB on the other. Perfect recipe for broken ports and cables. I break about a cable a week and break a device every now and then. Mostly doing very normal things like charging a phone in my pocket while hiking. USB-C seem…

I agree that usb-c connectors can be pretty fragile. To preserve mine, I've been charging my phone almost exclusively with a wireless charger.

Re: Explaining 4K 60Hz Video Through USB-C Hub

#40

Post by janlaureys »

BiteCode_dev wrote: post #36
nrclark wrote: post #32

USB-C is a train-wreck for those of us who work in electronics design. USB-C's chipset support isn't all that good, it seems like. With USB 3 type A, you pretty-much just run your USB lines to the ports on your CPU. Simple, straightforward. Manufacturers are happy to do it, because it's dirt cheap and requires nothing except the connectors and maybe some ESD protection. USB-C is a different beast entirely. Just to us…

I'm completely ok with it being complicated to design and cost 10 euros more if it delivers. And despite all its flaws, USBC does. It's small. It's reversible. I can charge all my devices on it: my samsung tablet, my oneplus phone, my logitech mouse, my jabra headphones, my switch and my XPS 13 laptop, which I can also dock to my screen/ethernet. It's amazing. So yes, I had to take the time to find the proper cable,…

I'm soon switching a lot of things to USB-C. What brands of cables would you recommend ?
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