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Displayport: A Better Video Interface

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Re: Displayport: A Better Video Interface

#281

Post by gsich »

dylan604 wrote: post #276
hot_gril wrote: post #171

Earlier quoted context omitted.

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

yes, still is.

Re: Displayport: A Better Video Interface

#282

Post by type0 »

dylan604 wrote: post #207
ShadowBanThis01 wrote: post #198

Earlier quoted context omitted.

It wasn't that short-lived. All DV cameras had FireWire. Although Sony, per its mania for undermining industry standards, created a bastardized version (called I-Link, ugh) whose connector lacked power and required a physical adapter. External FireWire drives (like LaCie's) were popular for quite a long time, since they required no extra power source.

Sony also gave us a professional studio DVCam deck that was SDI based that allowed you to connect to of them to get 4x dubbing speeds. Not once did it ever get used at the studio I was working. Nothing else in the shop used that format, so it was always just realtime SDI work. ahh, sony

Speaking of Sony video, they also have Gigabit Video Interface which uses some clever trickery to transmit clean signal in difficult environments like vehicles

https://web.archive.org/web/20210513082248/https://www.sony-...

Re: Displayport: A Better Video Interface

#283

Post by LelouBil »

A friend of mine had problems with his monitor, it would go into standby randomly when running certain games.

I asked him for details about his setup and I was pretty confused when he said the connector at the back of his monitor had screws but I saw the Nvidia control panel reporting HDMI.

Turns out he was using an HDMI to VGA adapter ! (GPU was outputting HDMI and screen consumed VGA).

I just told him to go buy a display port cable (since his GPU and monitor both had it) and he had no problem since.

Does anyone have insight about why the adapter could cause monitor standby in certain games ? It is really a peculiar issue.

Re: Displayport: A Better Video Interface

#285

Post by gsich »

jwells89 wrote: post #265
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?

The Apple Studio Display autodetects rotation and lets the connected computer know so it can adjust the picture accordingly, but it connects over Thunderbolt. It should be possible for monitors to do this over USB-C too, but I’m not sure about plain DisplayPort or HDMI.

I2C (Aux) could do this.

Re: Displayport: A Better Video Interface

#286

Post by dylan604 »

type0 wrote: post #282
dylan604 wrote: post #207

Earlier quoted context omitted.

Sony also gave us a professional studio DVCam deck that was SDI based that allowed you to connect to of them to get 4x dubbing speeds. Not once did it ever get used at the studio I was working. Nothing else in the shop used that format, so it was always just realtime SDI work. ahh, sony

Speaking of Sony video, they also have Gigabit Video Interface which uses some clever trickery to transmit clean signal in difficult environments like vehicles https://web.archive.org/web/20210513082248/https://www.sony-...

i closed the tab before looking for a date from when that was released. however, we've been converting video signals to use over Cat5/6 for a really long time since it supports running over much longer distances. can't believe, well, yeah, actually with Sony I can, that they went and made a whole format

Re: Displayport: A Better Video Interface

#287

Post by nyanpasu64 »

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…

One (extreeeemely pedantic) difference is that (I think) HDMI begins and ends its vsync pulses when the preceding hblank begins, whereas VGA begins and ends them slightly later when the preceding hsync pulse begins (I documented this at https://nyanpasu64.gitlab.io/blog/crt-modeline-cvt-interlaci...).

I also think that DP rouuuughly reflects CRT timings complete with active vs. blanking intervals, but doesn't actually have a fixed pixel clock (perhaps it does? I didn't quite figure out synchronous/asynchronous pixel transmission when reading the spec) and doesn't transmit hsync pulses once per scanline.

Re: Displayport: A Better Video Interface

#288

Post by sokoloff »

NavinF wrote: post #273
ComputerGuru wrote: post #192

Earlier quoted context omitted.

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

If you have multiple GPUs in a box, you often have to use the bottom slot as well as the close one. (Passing through dedicated GPUs to different VMs is one case that I’ve experienced.)

Re: Displayport: A Better Video Interface

#289

Post by nyanpasu64 »

rasz wrote: post #277
fanf2 wrote: post #221

Earlier quoted context omitted.

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.

I think that you can actually transmit audio, or other displays' signals (DisplayPort Multi-Stream Transport), in place of stuffing symbols.

Re: Displayport: A Better Video Interface

#290

Post by nyanpasu64 »

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…

Never mind KVM switches, I wish powering off my DP monitor while leaving wall AC power plugged in didn't appear as a display disconnect to the computer.
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