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Displayport: A Better Video Interface

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Re: Displayport: A Better Video Interface

#271

Post by deergomoo »

stephenr wrote: post #67
binkHN wrote: post #58

I didn’t realize Multi-Stream Transport (MST) requires OS support, and I was surprised to find out MacOS, with its great Thunderbolt support, does not support this. “Even” ChromeOS can do MST.

Technically macOS does support MST. But it only supports it to stitch together for a single display. It does not support daisy chaining two displays. Thankfully, every Mac for the last 7 years has Thunderbolt3 at least, so getting dual-4K-display from a single port/cable is still very doable, you just need a TB3 to dual DisplayPort or HDMI adapter.

You can daisy chain the Studio Display and Pro Display, and you could daisy chain the old Thunderbolt Display. Is that using some custom thing over Thunderbolt rather than MST?

Re: Displayport: A Better Video Interface

#272

Post by privacyking »

emilyst wrote: post #177
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.

If you get a thunderbolt 4 cable it can do everything, at least until the 80gbps one comes out

Re: Displayport: A Better Video Interface

#273

Post by NavinF »

ComputerGuru wrote: post #192
bee_rider wrote: post #3

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

It’s a problem when the x16 slot is the bottom-most and the orientation is such that the clicky thing you must depress is on the bottom side of the DP connector when plugged in, and your case has a ledge after the PCI slots so you cannot realistically depress the latch. Of course, no one would realistically encounter a case/GPU/cable combo like that. Right?

Your GPU should be in the x16 slot closest to the CPU because it has the most bandwidth.

tbh this sounds like a self-inflicted SFF build problem

Re: Displayport: A Better Video Interface

#274

Post by deergomoo »

IggleSniggle wrote: post #62
taeric wrote: post #32

Earlier quoted context omitted.

It was very convenient for me to have my headphones plugged into the monitor. Made it so I could plug a single cable over to my laptop and have basically everything else already done.

Every monitor I've ever had has had terrible coil-whine from the headphone jack. I always try them for exactly this reason, and get super annoyed each time. It didn't have to be this way!

I have this problem on my gaming monitor, thankfully it also has USB-A ports so a cheap adapter has solved it.

I have no idea if there are downsides to audio over USB-A but for my fairly basic use case (“being able to hear things and not hear coil whine”) it works pretty well.

Re: Displayport: A Better Video Interface

#275

Post by amelius »

deergomoo wrote: post #270
amelius wrote: post #262

Can we please get monitors that can find their signal within 100ms? Can we please get monitors that communicate their orientation (portrait/landscape etc.) to the computer?

> Can we please get monitors that can find their signal within 100ms? TVs too—with various HDR standards, VRR etc becoming more popular these days I quite often find myself staring at a blank screen for 5-10s

With Smart TVs being the only option these days, I'm thinking about building my own TV from a computer monitor.

Re: Displayport: A Better Video Interface

#276

Post by dylan604 »

hot_gril wrote: post #171
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…

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

I maybe mis-remembering, but was it possible to add FireWire to an existing PC with an expansion card? I know Thunderbolt was not possible from 3rd party vendors and only the mobo manufacturers could offer a card. I bought one to make a Hackintosh, but then a mobo firmware disabled the card because they didn't want to support it. I seem to recall Firewire being the same way

Re: Displayport: A Better Video Interface

#277

Post by rasz »

fanf2 wrote: post #221
rasz wrote: post #208

Earlier quoted context omitted.

>DisplayPort does away with all that legacy. You wish. DP sends exactly same bytes DVI does (blanking and all), just broken up into packets.

The important difference is that (like VGA) DVI and HDMI still dedicate particular physical wires to separate red, green, and blue channels. Display port does not shard individual pixels across multiple channels: all bits (all colours) of a pixel are sent on the same diffpair. If a DP link has multiple lanes then the bits of different successive pixels are sent on each lane.

This is great, but then they drop the ball by forcing garbage (“interspersed stuffing symbols”) between the packets instead of letting you use that BW.

Re: Displayport: A Better Video Interface

#278

Post by londons_explore »

kccqzy wrote: post #259
londons_explore wrote: post #64

Earlier quoted context omitted.

It should be. As soon as video data is in packets, it should be routable over a network like any other data. Give up the custom connectors, custom cables, etc. Need a wireless display? No worries, we can route the data over wifi too. Need 5 displays? Thats what an ethernet switch is for. Screen mirroring? We have multicast. Need a KVM? Well you can probably write a few scripts to change which computer your screen get…

Have you tried VNC over an Ethernet cable at all? What you are proposing is basically having a VNC-like protocol over IP over Ethernet. Now try it out and see how well it works. To be even more reductive, a thought experiment is to consider the classic USB. Why did people even invent USB in the first place in the 1990s? The first USB had only 12Mbps, not much better than the first Ethernet at 10Mbps which had existed…

The main delay in VNC is the software stack encoding and decoding the data.

A video-over-ethernet solution would likely have the GPU directly packetize the data into IP packets and route them direct to the network hardware without the CPU touching anything. The network would have QoS to guarantee the necessary bandwidth and guarantee a fixed latency and no packet loss (ie. there is no chance of a packet being dropped due to a queue overflowing, because we have already arranged a fixed bandwidth allocation for the whole network route).

Re: Displayport: A Better Video Interface

#279

Post by bleepblop »

aidenn0 wrote: post #159
bleepblop wrote: post #92

Earlier quoted context omitted.

If your receiver doesn't support eARC, you are definitely not getting full resolution audio.

I don't use ARC at all (all audio sources go through the receiver), so that's a non-issue for me.

That's fine. Let me rephrase: if you're not using the latest and greatest HDMI protocol you're not getting full fidelity audio.

Re: Displayport: A Better Video Interface

#280

Post by gsich »

madars wrote: post #200
TazeTSchnitzel wrote: post #143

The amazing thing about DVI, and by extension HDMI, is that it's just VGA but digital, with all the timing and synchronisation complexity that implies. Recall that DVI can have both an analog (VGA/DVI-A) and digital (DVI-D) signal in the same cable. They aren't independent; they share some pins and have the same timing. You could have made a CRT monitor that used DVI-D just by adding a DAC, though I'm not sure if any…

This also has side-channel implications, and is a reason why eDP is recommended in voting applications. https://www.eerstekamer.nl/nonav/overig/20160428/richtlijnen... >DisplayPort uses a scrambler as part of its line encoding in order to flatten the Fourier spectrum of its emissions and suppress spectral peaks caused by particular image contents. This reduces the chances of any particular image content causing a pro…

Voting computers are not recommended anyways.
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