Displayport: A Better Video Interface • Hacker News Board

Re: Displayport: A Better Video Interface

#21

Post by bandrami » Tue, Jul 11, 2023, 3:53 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's an oscilloscope screen that does the conversion in software and was the bane of my existence last year.

Re: Displayport: A Better Video Interface

#22

Post by puzzlingcaptcha » Tue, Jul 11, 2023, 3:53 PM UTC

jsheard wrote: post #13

Salgat wrote: post #9

Earlier quoted context omitted.

DisplayPort and HDMI's max length is 15m, compared to USB 3.1's 3m.

That very much depends on how much bandwidth you're pushing through the cable, older versions of HDMI could tolerate long cable runs but HDMI 2.1 is also limited to about 3m unless you use an expensive active optical cable. DisplayPort 2.0/2.1 is taking forever to come to market but it's going to be similarly limited in its high bandwidth modes when it does arrive.

40G FRL5 (4K @ 144Hz) seems to work just fine for me with a 8m HDMI 2.1-certified cable (copper). But I had trouble finding longer ones from the same vendor which makes me suspect it is getting close to the limit.

Re: Displayport: A Better Video Interface

#23

Post by remix2000 » Tue, Jul 11, 2023, 3:53 PM UTC

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.

Re: Displayport: A Better Video Interface

#24

Post by lucideer » Tue, Jul 11, 2023, 3:54 PM UTC

Veliladon wrote: post #17

HDMI predates DP by 5 years, switching wouldn't enable any specific use case, and that 5 years head start means HDMI has market inertia. Yes we should use it because it's better but the practicality? There's so much gear that's HDMI that would have to be replaced or require new active adaptors. It's so much industry and consumer effort for such a marginal gain.

Forget all the other pros/cons - MST makes it worth any industry & consumer effort alone.

Re: Displayport: A Better Video Interface

#25

Post by nfriedly » Tue, Jul 11, 2023, 3:56 PM UTC

I'm annoyed nvidia for putting the current generation of HDMI on their recent GPUs, but leaving them with an outdated version of DisplayPort.

For a long time, my advice to anyone was to always choose DisplayPort whenever it was an option. But now that has to have the caveat of "if you have a new high-end GPU and a fancy high refresh rate monitor, HDMI might actually be better for your situation"

Re: Displayport: A Better Video Interface

#26

Post by lucideer » Tue, Jul 11, 2023, 3:56 PM UTC

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* alternative output I actually want to direct my audio to.

The only time I've ever gotten high-quality audio output over HDMI is via ARC, which says a lot about the need for HDMI audio...

* When I say "much higher-quality", I don't mean HDMI is a low-quality audio transport, I mean the HDMI output devices more often than not have inferior audio output to some other bluetooth / 3.5mm jack device I am using.

Re: Displayport: A Better Video Interface

#27

Post by nfriedly » Tue, Jul 11, 2023, 3:57 PM UTC

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.

I have two different LG monitors that both support audio over the DP cable.

Re: Displayport: A Better Video Interface

#28

Post by johnwalkr » Tue, Jul 11, 2023, 3:58 PM UTC

Zekio wrote: post #20

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

no vendors implemented it, so whenever you are currently doing hdmi over usb-c it is actually hdmi over dp over usb-c

Which is fine and should stay well-supported because HDMI is also here to stay. The trend for TVs is to include HDMI ports but no displayports.

Re: Displayport: A Better Video Interface

#29

Post by gjsman-1000 » Tue, Jul 11, 2023, 3:59 PM UTC

nfriedly wrote: post #25

I'm annoyed nvidia for putting the current generation of HDMI on their recent GPUs, but leaving them with an outdated version of DisplayPort. For a long time, my advice to anyone was to always choose DisplayPort whenever it was an option. But now that has to have the caveat of "if you have a new high-end GPU and a fancy high refresh rate monitor, HDMI might actually be better for your situation"

> I'm annoyed nvidia for putting the current generation of HDMI on their recent GPUs, but leaving them with an outdated version of DisplayPort.

That was due to unfortunate timing where HDMI had the specifications ready before DisplayPort did.

Re: Displayport: A Better Video Interface

#30

Post by masklinn » Tue, Jul 11, 2023, 3:59 PM UTC

hadrien01 wrote: post #11

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

There's also Thunderbolt over USB-C that does DisplayPort, but it doesn't support all the same versions as DisplayPort over USB-C. And there's also USB 4 but I don't know/understand if it changes anything.

I think the most applicable bit is that USB4 adds tunneling modes, aside from alternate mode.

I'm not entirely clear, but from my understanding alternate mode means the physical connection gets switched over, while tunneling means the tunneled data is sent over USB (so the communication on the wire is USB all along, you get nesting).