Displayport: A Better Video Interface • Hacker News Board

Re: Displayport: A Better Video Interface

#121

Post by jchw » Tue, Jul 11, 2023, 4:56 PM UTC

tivert wrote: post #77

Are there any KVM switches that do Displayport well (i.e. where switching between inputs does not look like a display disconnect to the PC)? I'm still using HDMI because I like to share my home multi-monitor setup between my personal machine and my work laptop, and the KVM switches are able to fool the PCs into thinking the monitor are always connected. Years ago I tried a Displayport switch, but it could not -- I as…

None of them are perfect, but I've heard good things about the DP switch from Level1techs. The thing is, all of them are a little tricky, but they mostly differ in how quirky they are, and I suspect the reason why people like the Level1techs DP switch is that they seem to at least try to alleviate some of the issues DP switches tend to get into.

https://store.level1techs.com/products/14-kvm-switch-dual-mo...

The startech one I have is alright... But Apple computers absolutely hate it and frequently refuse to display, and sometimes Windows gets stuck and USB devices stop working. Strangely enough... Linux doesn't ever have any problems with either display or input. A rare win, but fine by me.

Re: Displayport: A Better Video Interface

#122

Post by askura » Tue, Jul 11, 2023, 4:56 PM UTC

The only downside with DP is just devices that actually have that versus HDMI / Mini hdmi.

This post though has made me annoyed as DP is clearly the better standard.

Re: Displayport: A Better Video Interface

#123

Post by tshaddox » Tue, Jul 11, 2023, 4:56 PM UTC

> However, I’d like to tell you that you probably should pay more attention to DisplayPort – it’s an interface powerful in a way that we haven’t seen before.

Lines like that really show just how long it can take for standards to get on the radar of mainstream tech culture. I remember hearing about and being excited about DisplayPort's move to packetized digital video in college in 2008, and seeing the first Macs with MiniDisplay port later that year (or perhaps it was in 2009)!

I was actually under the impression that it has been well-known and commonplace for hobbyist and enthusiast PCs for well over 10 years, but I'm probably wrong about that!

Re: Displayport: A Better Video Interface

#124

Post by _kb » Tue, Jul 11, 2023, 4:56 PM UTC

pid-1 wrote: post #48

Sorry if that sounds stupid, but why isn't Ethernet used for this sort of high bw signaling?

Because (consumer) ethernet is low bandwidth compared to whats needed for video. DisplayPort 2.0 provide a 80Gbps link. HDMI is 48Gbps. Both already use DSC which is a mezzanine compression as this is already saturated for immediate needs.

Ethernet is absolutely used for media transport outside of the consumer space. Particularly where there's a need to distribute signals further than what DP or HDMI can provide. The challenge is this always comes with a trade off. Any compression will result in some mix of a loss of image quality, increase to latency, and cost. What that mix looks like differs across applications.

See https://sdvoe.org/, https://ipmx.io/, https://www.intopix.com/flinq, https://www.aspeedtech.com/pcav_ast1530/ for more in that space.

https://hdbaset.org/ is the other key tech. That uses the same PHY as ethernet, but is a proprietary signal.

Re: Displayport: A Better Video Interface

#125

Post by J_Shelby_J » Tue, Jul 11, 2023, 4:57 PM UTC

lucideer wrote: post #26

remix2000 wrote: post #23

With HDMI, I have both video and audio traveling over a single cable. That is _extremely_ convenient. DP _theoretically_ supports audio too, but AFAIK that's not widely implemented.

> That is _extremely_ convenient. I'm open to having my mind changed but I have not really experienced this extreme convenience in practice. The vast majority of things I plug a HDMI cable into either don't have speakers or if they do, the speakers are a bad quality afterthought. In actual fact, what has been an extreme inconvenience is the OS thinking I want HDMI audio instead of whatever much higher-quality* altern…

Audio over HDMI or DP has never been anything but a nuisance on my windows workstations. Windows finds a way to set the speaker monitor/mic as the system defaults at least once a month for me. Every GPU driver update I end up disabling the display's audio in device manager. Hrm... maybe I could write a script to do it at boot.

I think it could make sense in budget friendly setups, but... personally I'd pay extra to not have to deal with the nuisance and security risk of microphone input I can't physically disable.

Re: Displayport: A Better Video Interface

#126

Post by cassianoleal » Tue, Jul 11, 2023, 4:57 PM UTC

bluedino wrote: post #109

BadBadJellyBean wrote: post #4

I just wish there was only one connector. Either HDMI or DP. I don't care.

Oh, but there's a third. MiniDP. I have a pile of useless cables/adapters now, since Apple started using them but replaced them with USB-C back in 2015.

There is also mini and micro HDMI.

https://www.howtogeek.com/745530/hdmi-vs-mini-hdmi-vs-micro-...

Re: Displayport: A Better Video Interface

#127

Post by mywittyname » Tue, Jul 11, 2023, 4:57 PM UTC

lucideer wrote: post #26

remix2000 wrote: post #23

With HDMI, I have both video and audio traveling over a single cable. That is _extremely_ convenient. DP _theoretically_ supports audio too, but AFAIK that's not widely implemented.

> That is _extremely_ convenient. I'm open to having my mind changed but I have not really experienced this extreme convenience in practice. The vast majority of things I plug a HDMI cable into either don't have speakers or if they do, the speakers are a bad quality afterthought. In actual fact, what has been an extreme inconvenience is the OS thinking I want HDMI audio instead of whatever much higher-quality* altern…

I use my PC to drive a TV for gaming and all I have to do is switch the sound output in Windows from Speakers to TV and I'm good to go. No need for splitters and multiple cables to get sound to both devices. The only thing I would change is to have Windows support outputting audio to both devices regardless, but keeping the settings menu open to the right page isn't really an inconvenience.

All of my consoles work the same way: just run a single HDMI cable for each one.

The counter point might be that my TV would have "bad audio." But I don't think so (at least not at the volumes I prefer), and even if it did, it supports audio out to connect the TV audio to a separate hi-fi.

Re: Displayport: A Better Video Interface

#128

Post by wmf » Tue, Jul 11, 2023, 4:58 PM UTC

yellowapple wrote: post #93

londons_explore wrote: post #66

Earlier quoted context omitted.

If this were true, then people would be running datacenter networking over HDMI. Data is data - there is no benefit to designing two entirely different transport mechanisms for video vs other data. You could argue that video data has a deadline to meet - but ethernet already has lots of mechanisms for QoS and bandwidth reservations to make sure that someones torrents don't interrupt something latency sensitive. Sure,…

> If this were true, then people would be running datacenter networking over HDMI. Why would they? If they need more bandwidth than what Ethernet provides, they'd probably just bite the bullet and go with fiber. ...which punts the previous question to why the industry hasn't gone all-in with fiber optic display connectors, like it has with TOSLINK for S/PDIF in the audio world.

TOSLINK was a gimmick. In reality, optical transceivers are expensive and are only used when copper can't do the job.

Re: Displayport: A Better Video Interface

#129

Post by ianburrell » Tue, Jul 11, 2023, 5:00 PM UTC

vel0city wrote: post #12

jsheard wrote: post #8

Earlier quoted context omitted.

It also allows the transmission of HDMI over USB-C, so you still have two competing standards

It allows it, but can you actually buy any products for it? https://www.notebookcheck.net/The-demise-of-HDMI-over-USB-C-... > True USB-C to HDMI adapters are no longer going to be a thing. The HDMI Alt Mode is more or less history, and DisplayPort has won. Notebookcheck spoke to HDMI LA and the USB-IF about it. > HDMI LA said that it doesn't know of a single adapter that has ever been produced. Similarly, at the USB…

There is also MHL alt mode. The HDMI alt mode was horrible because it used the whole USB-C cable as HDMI cable preventing any other users. MHL is HDMI but over a single pair.

My understanding is that all the USB-C to HDMI adapters are using DisplayPort because that is more widely supported by devices. And the conversion chips are just as cheap as MHL to HDMI.

Re: Displayport: A Better Video Interface

#130

Post by NavinF » Tue, Jul 11, 2023, 5:02 PM UTC

wcfields wrote: post #37

If we lived in a just, and virtuous world we'd all be using cheap coaxial cables with BNC connectors via whatever version of SDI is the highest bit rate.

That would suck. I'd need at least 4 coax cables for each monitor.

Btw DP cables are often twinax and eDP cables are often microcoax.

In a just, and virtuous world we'd all be using cheap SMF cables with LC connectors