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HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

arstechnica.com

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Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#151

Post by jwells89 »

Dalewyn wrote: post #66
redox99 wrote: post #62

Luckily with mid and high end monitors, DisplayPort is the standard. I don't understand why TVs don't come with even a single DisplayPort though. Maybe they are paid off by the HDMI forum?

Most people don't connect a computer to their TV, assuming they even have a computer at all. And assuming they do, they all have HDMI anyway. As for everything else most people would connect to their TV, they all have HDMI and precisely none have DisplayPort. Given that, supporting DisplayPort is an unnecessary expenditure on bill of materials and labor for TV manufacturers.

It’s niche I’ll admit, but a while back the lack of support for DisplayPort in home theater equipment bit me because I had an Oculus Rift (original) hooked up to the same machine, using the only HDMI output on the computer’s GPU which meant hooking it up to the TV (through a receiver) required a DisplayPort → HDMI adapter.

Thing is, DP → HDMI adapters all suck when you’re using them to send anything but a basic 1080p picture. They nearly all fail or struggle with uncompressed 4K. I tried several different cables and adapters and despite marketing claims, they all had trouble. The best was one that was externally powered via USB, but even it exhibited quirks.

I no longer have the Rift hooked up to that machine which freed its HDMI port up, but I too wish TVs and receivers had even just one DisplayPort.

Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#152

Post by jwells89 »

raarts wrote: post #67
Dalewyn wrote: post #66

Earlier quoted context omitted.

Most people don't connect a computer to their TV, assuming they even have a computer at all. And assuming they do, they all have HDMI anyway. As for everything else most people would connect to their TV, they all have HDMI and precisely none have DisplayPort. Given that, supporting DisplayPort is an unnecessary expenditure on bill of materials and labor for TV manufacturers.

It’s a recently popular thing to use a tv as monitor.

If I were to do this I think I’d try to find a BFGD (big format gaming display), which is a type of screen that’s sized like a TV but behaves more like a monitor and usually has a DisplayPort.

Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#153

Post by paulmd »

oskarw85 wrote: post #143
dtx1 wrote: post #13

Earlier quoted context omitted.

> A cheap DP-HDMI dongle makes all this go away. As long as VESA doesn't behave the same way, anyway. You can even get cables that are DP on the input and HDMI on the output with minimal bulk.

But this feature works by transmitting HDMI signals so you still need to implement the software part in question.

No, it doesn’t. Hdmi alt mode doesn’t exist in the real world.

Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#154

Post by iforgotpassword »

jwells89 wrote: post #151
Dalewyn wrote: post #66

Earlier quoted context omitted.

Most people don't connect a computer to their TV, assuming they even have a computer at all. And assuming they do, they all have HDMI anyway. As for everything else most people would connect to their TV, they all have HDMI and precisely none have DisplayPort. Given that, supporting DisplayPort is an unnecessary expenditure on bill of materials and labor for TV manufacturers.

It’s niche I’ll admit, but a while back the lack of support for DisplayPort in home theater equipment bit me because I had an Oculus Rift (original) hooked up to the same machine, using the only HDMI output on the computer’s GPU which meant hooking it up to the TV (through a receiver) required a DisplayPort → HDMI adapter. Thing is, DP → HDMI adapters all suck when you’re using them to send anything but a basic 1080p…

It's complicated, but the tldr is: use a DP++ type 2 adapter that advertises 4k compat.

DP++ adapters tell the GPU to output an HDMI signal instead (DP is an entirely different protocol), and then just level-shift the signal. Type 1 adapters are limited to i-forgot-how-many MHz which means no more than 1080p60. Type 2 adapters contain a tiny 256 byte rom that tells the GPU its maximum supported bandwidth.

Other adapters are active, they convert the signal and thus add latency, and often need external power so can get quite hot.

Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#155

Post by iforgotpassword »

megous wrote: post #119
fps_doug wrote: post #115

Earlier quoted context omitted.

Sure, but this is a hypothetical scenario, focusing on the legal aspects.

Legal aspects of something that can never happen? Why? Try legal aspects of reverse engineering a binary driver. That's more realistic.

But the question is not whether it's legal to reverse engineer a binary. The question is whether someone with no affiliation to neither the HDMI forum nor AMD could contribute the according code to the AMD driver which is part of the Linux Kernel, regarding legal implications.

Reverse engineering of binaries is pretty much a solved problem from the legal standpoint.

Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#156

Post by coryfklein »

redox99 wrote: post #62

Luckily with mid and high end monitors, DisplayPort is the standard. I don't understand why TVs don't come with even a single DisplayPort though. Maybe they are paid off by the HDMI forum?

Probably because nothing that plugs into TVs has DisplayPort? Blu-Ray players, receivers, Apple/Android TV, etc.

Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#157

Post by Gare »

oskarw85 wrote: post #141
Gare wrote: post #20

Earlier quoted context omitted.

Locking is a feature, not a bug

Especially when your monitor falls down from your desk instead of simply disconnecting at the plug.

Easily solved by proper cable management.

Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#158

Post by indrora »

coryfklein wrote: post #156
redox99 wrote: post #62

Luckily with mid and high end monitors, DisplayPort is the standard. I don't understand why TVs don't come with even a single DisplayPort though. Maybe they are paid off by the HDMI forum?

Probably because nothing that plugs into TVs has DisplayPort? Blu-Ray players, receivers, Apple/Android TV, etc.

You can actually blame DVI for this one.

DVI connectors offered analog VGA for years. This meant that graphics card vendors could put one port on their card that did both, huzzah, and a passive adapter got you VGA out of DVI.

DVI is ahead of DisplayPort by 8 years. The DMCA is passed and HDCP becomes a Thing. Many card vendors do put DisplayPort on their cards, since it's the "Professional" standard for video, but that isn't until 2008 or so. DisplayPort would not be widely adopted until 2012-ish.

Fast forward, VGA dies. DisplayPort and DVI-Dual link are there. DVI Dual is forwards-ish compatible with upcoming HDMI displays for TVs, as pushed by the MPEG-LA and DVD makers. In 2009, less than 5% of devices shipped had DisplayPort on them. DisplayPort at this time also cannot handle the two most popular color spaces in use: sRGB and Adobe RGB 1998.

Part of the issue was a perception thing: Displayport was widely adopted by Apple early on, and consumer understanding of Mini DisplayPort was that it was an Apple standard, rather than an open standard, and this further pushed the port out of the limelight.

Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#159

Post by jasomill »

jwells89 wrote: post #151
Dalewyn wrote: post #66

Earlier quoted context omitted.

Most people don't connect a computer to their TV, assuming they even have a computer at all. And assuming they do, they all have HDMI anyway. As for everything else most people would connect to their TV, they all have HDMI and precisely none have DisplayPort. Given that, supporting DisplayPort is an unnecessary expenditure on bill of materials and labor for TV manufacturers.

It’s niche I’ll admit, but a while back the lack of support for DisplayPort in home theater equipment bit me because I had an Oculus Rift (original) hooked up to the same machine, using the only HDMI output on the computer’s GPU which meant hooking it up to the TV (through a receiver) required a DisplayPort → HDMI adapter. Thing is, DP → HDMI adapters all suck when you’re using them to send anything but a basic 1080p…

At least a few active DP → HDMI 2.0 are okay at 4kp60. For example, these[1][2] do 4:4:4/RGB 4kp60 fine, though they're limited by HDMI 2.0 to 8 bits per color channel at 4kp60 (higher bit depths work fine at lower resolutions and frequencies, or with chroma subsampling).

In my testing (several years ago), at least half a dozen other similarly-priced DP → HDMI 2.0 adapters purchased from Amazon were limited to chroma subsampled output (4:2:2 or 4:2:0) at 4kp60, which is obviously unacceptable for desktop use, so I do see your point.

I've used the linked adapters successfully now for several years with both a 2013 Mac Pro and a pair of DP-only AMD GPUs (WX 3200 and WX 4100), all connected to a 2019 LG TV, and, while testing, confirmed all claimed signal outputs using an HDFury Vertex.

[1] https://www.amazon.com/dp/B00S0BWR2K

[2] https://www.amazon.com/dp/B00S0C7QO8

Re: HDMI Forum does not allow an open source implementation of the HDMI 2.1 spec

#160

Post by rickdeckard »

salviati wrote: post #41
rickdeckard wrote: post #19

Earlier quoted context omitted.

Also, that someone without contracts would probably need to call it different than "HDMI", because the term itself is trademarked and only licensed to Members (like "Wi-Fi" and "Bluetooth"). So a different term would be needed (like "WLAN" or "BT" is used by non-members)

I checked and found this info from the Wi-Fi Alliance [0]: > Select brands and logos are offered license free and intended to be used widely throughout the Wi-Fi ecosystem by Wi-Fi Alliance members, non-members, industry partners, media, and analysts to describe products, technology, network deployments, and operating system support. It sounds to me like anyone could use the trademark "Wi-Fi", since it's listed in th…

> It sounds to me like anyone could use the trademark "Wi-Fi", since it's listed in the freely available ones.

Yes, to describe Wi-Fi as defined by the Wi-Fi Alliance, not to describe anything the Alliance does NOT consider compliant.

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