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Displayport: A Better Video Interface

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Re: Displayport: A Better Video Interface

#231

Post by bbatha »

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…

I had the startech one the siblings have mentioned but that wasn't very good and didn't do EDID emulation correctly. This CKL one [0] has been working really well, and supports USB 3 which is a nice bonus so I can share my webcam. Though sometimes after wake up my macbook forgets about my second monitor (I have an M1 connected to a cable matters thunderbolt dock), my windows machine which has direct DP connections doesn't have the same issue.

0: https://www.amazon.com/gp/product/B09STVW821/

Re: Displayport: A Better Video Interface

#232

Post by chx »

someplaceguy wrote: post #217
chx wrote: post #212

Earlier quoted context omitted.

> DSC is most often used in a Constant Bit Rate (CBR) mode, where the number of coded bits generated for a slice is always a constant that is generally equal to the bit rate multiplied by the number of pixels within the slice https://vesa.org/wp-content/uploads/2020/08/VESA-DSC-Source-...

Ah, so basically this is typically used as lossy compression with a constant bit rate, which makes the bandwidth usage predictable/constant but depending on the pictures being shown (and the noise level?), it can lead to some visual degradation (which they say is usually imperceptible). That's interesting and surprising to me.

If you consider how ~1:18 is considered visually lossless for x.264, a compression of 1:3 is very very likely can be achieved visually lossless indeed.

Re: Displayport: A Better Video Interface

#233

Post by sedatk »

Ajedi32 wrote: post #210

> A carefully shaped money-backed lever over the market is absolutely part of reason you never see DisplayPort inputs on consumer TVs, where HDMI group reigns supreme, even if the TV might use DisplayPort internally for the display panel connection. Curious about this. Is the HDMI standards group engaging in anti-competitive behavior to prevent DisplayPort from taking over on TVs? I've always assumed it was just mome…

> Is the HDMI standards group engaging in anti-competitive behavior

They don't need to, the whole industry is behind it:

> The HDMI founders were Hitachi, Panasonic, Philips, Silicon Image, Sony, Thomson, and Toshiba.

> HDMI has the support of motion picture producers Fox, Universal, Warner Bros. and Disney, along with system operators DirecTV, EchoStar (Dish Network) and CableLabs.

Re: Displayport: A Better Video Interface

#234

Post by SV_BubbleTime »

muhammadusman wrote: post #172
smachiz wrote: post #60

Earlier quoted context omitted.

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/

No one would be able to answer this for you in your house with your cables with your speakers. Get another one and test it.

Re: Displayport: A Better Video Interface

#236

Post by jamiek88 »

chx wrote: post #232
someplaceguy wrote: post #217

Earlier quoted context omitted.

Ah, so basically this is typically used as lossy compression with a constant bit rate, which makes the bandwidth usage predictable/constant but depending on the pictures being shown (and the noise level?), it can lead to some visual degradation (which they say is usually imperceptible). That's interesting and surprising to me.

If you consider how ~1:18 is considered visually lossless for x.264, a compression of 1:3 is very very likely can be achieved visually lossless indeed.

Is it not compressing an already compressed image though?

Re: Displayport: A Better Video Interface

#237

Post by immibis »

masklinn wrote: post #19
jayd16 wrote: post #6

Earlier quoted context omitted.

It'll be the USB-C port.

For laptops it's pretty clearly USB-C with DP alt mode, just way too convenient to use a display as a charging hub. Desktop CG manufacturers don't care and it doesn't really drive sales (NVidia has completely removed it, and AMD's tends to be pretty buggy, it's really just DP over a USB-C port) so you need conversion add-in cards (usually from your mobo manufacturer). Also display manufacturers, standard connectivity…

Many connectors in one. Is the video output the left port or the right one? How about the charging port?

Re: Displayport: A Better Video Interface

#238

Post by ApolIllo »

gjsman-1000 wrote: post #43
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.

For some reason, outside of video, HDMI knows how to shoot themselves in the foot almost as well as the USB-IF. HDMI CEC? Has anyone actually got that working correctly? Anyone remember Ethernet over HDMI? Apparently that was a thing. (Not to be confused with HDMI over Ethernet, which actually has some uses.) HDMI for soundbars? We got ARC ports (Audio Return Channel). But it was buggy, didn't support lossless audio,…

HDMI-CEC is great for TVs but when I searched recently I found that both Nvidia and AMD do not support HDMI-CEC. This was disappointing to find out when I built an HTPC for my TV.

Re: Displayport: A Better Video Interface

#239

Post by xboxnolifes »

xxpor wrote: post #117
hazebooth wrote: post #114

Earlier quoted context omitted.

Were you thinking of Level1techs? https://store.level1techs.com/products/14-kvm-switch-triple-...

I'm 90% sure it was, but it looks like they did a major UI update to the site so it's not triggering the "that was it!" lightbulb in my brain.

Alternatively, you may have been thinking about ConnectPro. I ordered a kvm from them around the same timeframe and it was delayed quite a bit from backorder. (Though, they also did a major UI change, so might not be able to tell either).

Re: Displayport: A Better Video Interface

#240

Post by qwertox »

This is a really well written article. If you haven't bothered reading about DisplayPort because you knew VGA, somewhat knew DVI and thought that HDMI is the culmination of it all, where then DisplayPort is just some further kind of evolution, this article does a really good job at explaining how DP is very different and something new, something worth knowing about.

The core sentence which made me actually read the article was "DisplayPort sends its data in packets." and does a good job at explaining what this means and how this differs from HDMI.

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