Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Displayport: A Better Video Interface

hackaday.com

Post reply on HN
Print view View original

171–180 of 426 posts

Re: Displayport: A Better Video Interface

#171

Post by hot_gril »

dylan604 wrote: post #164
hot_gril wrote: post #139

Earlier quoted context omitted.

That, and a similar line might've been said about FireWire, which didn't really make it.

Maybe I agree with that, but I also know that firewire helped usher in the digital video era. It allowed the transition from tape based acquisition when media cards were prohibitively expensive. Audio/Video/Deck control all down one single cable straight from the camera to the computer was what really kicked the prosumer market into being able to lean closer to pro than consumer. Now that media cards are actually aff…

Yeah, FireWire was a necessity at the time for certain use cases. Even basic consumer digital camcorders required FW400 to pull onto a PC.

Re: Displayport: A Better Video Interface

#172

Post by muhammadusman »

smachiz wrote: post #60
muhammadusman wrote: post #50

This post was informative and I didn't realize just how different DisplayPort is from HDMI. Recently, I got a desktop dock that uses DisplayPort instead of HDMI to connect to my monitor. My monitor has 2 HDMI ports, 1 Type-C, and 1 DisplayPort. So far things have been fine but I did notice that the audio is choppy no matter what I do. I thought it was the dock but audio going from my computer > dock > my webcam's spe…

It might be your dock. Check to see whether it's USB or Thunderbolt. Thunderbolt docks are more expensive, but considerably more efficient and faster than USB (assuming your laptop/device supports Thunderbolt). Thunderbolt docks are basically PCIe extension devices, whereas USB docks attach everything as USB, with all the common challenges USB has on systems (like dropped audio when the CPU is busy).

Thanks for the info. The dock is the CalDigit TS3 Plus dock and I’m using it with an LG monitor. Their page says it’s a Thunderbolt dock so I wonder if there’s anything else about this particular dock that could be causing this issue. Btw when the monitor was connected over HDMI, it was fine playing audio.

https://www.caldigit.com/ts3-plus/

Re: Displayport: A Better Video Interface

#173

Post by ansible »

wtallis wrote: post #147
crazygringo wrote: post #119

> Just like most digital interfaces nowadays, DisplayPort sends its data in packets. This might sound like a reasonable expectation, but none of the other popular video-carrying interfaces use packets in a traditional sense – VGA, DVI, HDMI and laptop panel LVDS all work with a a stream of pixels at a certain clock rate. Funny, a stream of data at a constant rate makes much more sense to me intuitively than packets,…

> Funny, a stream of data at a constant rate makes much more sense to me intuitively than packets, specifically for uncompressed video. Sure, until you start trying to design the transceivers and realize that supporting two or three fixed standard data rates is a lot simpler than supporting a continuously-variable clock speed. Every other high-speed digital interface operates at just a few discrete speeds: SATA/SAS,…

> ... If we hadn't wasted a decade using CRT timings (and slight modifications thereof) to drive LCDs over digital links ...

Don't forget the decade or so (late 1990's to early 2000's) where we were driving LCDs over analog links (VGA connectors).

I had purchased a pair of Silicon Graphics 1600SW monitors back in the day, which required a custom Number Nine graphics card with an OpenLDI display interface. It was many years since those were introduced to the market that DVI finally started becoming commonplace on PC graphics cards.

Using the mass-market LCD monitors in the late 1990's was a frustrating affair, where you had to manually adjust the timing synchronization of the analog signal.

Re: Displayport: A Better Video Interface

#174

Post by Steltek »

jchw wrote: post #121
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 star…

I had much more serious problems with a StarTech DP KVM and Macs. My Macbook would hang and crash-reboot. Both on the initial plug-in and on switching inputs.

Everything else seemed to handle it fine with Linux being especially unphased, as usual.

Re: Displayport: A Better Video Interface

#175

Post by adrian_b »

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 rather old NVIDIA GPUs and Dell monitors, and both the GPUs and the monitors support audio over DisplayPort.

I doubt that there exists any reasonably recent GPU that does not support audio over DisplayPort, so if there are problems they might be caused by the monitors. I have no idea how many monitors have speakers and DisplayPort without supporting audio over DP.

Re: Displayport: A Better Video Interface

#177

Post by emilyst »

chx wrote: post #168

> However, if you don’t need the full bandwidth that four lanes can give you, a DP link can consist of only one or two main lanes resulting in two This is how many USB C docks operate. The USB C connector also has four high speed lanes and there's a mode where two are assigned to carry DisplayPort data and two are assigned to be TX and RX respectively for USB. Until DP 1.4 appeared, this meant you were quite limited…

> Ps.: When I say Thunderbolt, I am well aware of how Thunderbolt 4 is just USB4 with optional features made mandatory. It's not relevant to the discuss at hand.

Dear God, I hope this situation settles down in the near future. As it is I have years of USB-C-looking cables that all do different things but are visually indistinguishable.

Re: Displayport: A Better Video Interface

#178

Post by lucideer »

hot_gril wrote: post #118
lucideer wrote: post #24

Earlier quoted context omitted.

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

How many people use multiple external displays? For the power users who do, there are already good enough solutions.

I don't have data on this but if my anecdata is anything to go by, power users aren't your typical multi-monitor users...

Re: Displayport: A Better Video Interface

#179

Post by green-salt »

bee_rider wrote: post #3

I just like the little retaining clips, and the satisfying little click you hear/feel when plugging them in.

I have a love/hate relationship with them for when the release tab is in a hard to reach area or doesn't release well, but that's usually the cable's fault. Love that tactile sensation of it being properly mated.

Re: Displayport: A Better Video Interface

#180

Post by dylan604 »

pdmccormick wrote: post #169
dylan604 wrote: post #164

Earlier quoted context omitted.

Maybe I agree with that, but I also know that firewire helped usher in the digital video era. It allowed the transition from tape based acquisition when media cards were prohibitively expensive. Audio/Video/Deck control all down one single cable straight from the camera to the computer was what really kicked the prosumer market into being able to lean closer to pro than consumer. Now that media cards are actually aff…

I once purchased a FireWire multi-channel audio interface with the express intent of reverse engineering the protocol in order to add Linux support. I purchased a specialized PCI card that was intentionally non-standard (not OHCI 1394) but could snoop and capture traffic between a device and a host. I chipped away at deciphering a register map for awhile, but eventually better USB audio devices came along that had mo…

you are a glutton for punishment. a hacker after my own heart!

i have so many unfinished things where i just knew something could be figured out, only to not succeed. but it sure is fun trying on top of learning new things as well.

Post reply on HN