[HN Gopher] HDMI Forum Rejects Open-Source HDMI 2.1 Driver Suppo...
       ___________________________________________________________________
        
       HDMI Forum Rejects Open-Source HDMI 2.1 Driver Support Sought by
       AMD
        
       Author : jiripospisil
       Score  : 197 points
       Date   : 2024-02-28 20:53 UTC (2 hours ago)
        
 (HTM) web link (www.phoronix.com)
 (TXT) w3m dump (www.phoronix.com)
        
       | silisili wrote:
       | Serious question, what if they just ignore the Forum and do it
       | anyways?
        
         | mperham wrote:
         | They will get sued and lose.
        
         | baby_souffle wrote:
         | > Serious question, what if they just ignore the Forum and do
         | it anyways?
         | 
         | Probably makes it tricky to get HDMI forum's blessing for any
         | future devices. AFAIK, the hdmi standards are public-ish so
         | anybody can create a device that is HDMI compatible but you're
         | only allowed to put "HDMI" on the packaging / marketing
         | material with the forum's blessing.
        
         | xnyan wrote:
         | HDMI((r)) is a trademark as well as a proprietary protocol. The
         | only way to legally use the HDMI label is with approval of the
         | forum.
        
           | toast0 wrote:
           | Just call it a 19-bin display connector in that case. Or only
           | put in dual-mode display port connectors (DP++), and let
           | people get passive adapters (maybe bundle them for a bit; you
           | can probably label the passive adapters as HDMI)
        
             | notpushkin wrote:
             | > Just call it a 19-bin display connector in that case
             | 
             | Flipper x Raspberry Pi did exactly that just a couple days
             | ago: https://blog.flipper.net/introducing-video-game-
             | module-power...
             | 
             | > Video Out port: DVI-D signal in 640kh480 px, 60 Hz. The
             | port supports a well-known video standard that we can't
             | name due to copyright limitations :shush: The first letter
             | is H, and the last one is I.
        
             | 0xcde4c3db wrote:
             | This is pretty much an actual strategy. The
             | academic/crowdfunded ULX3S FPGA development board went with
             | calling it "GPDI" (general-purpose digital interface).
             | Other strategies include labeling the connector with a
             | little TV/monitor icon, calling it "digital video", or just
             | having a little diagram in the marketing/documentation
             | material with it connected to a TV with a vaguely HDMI-
             | shaped cable.
        
         | Crosseye_Jack wrote:
         | At best: Get kicked out of the forum and can never support HDMI
         | products going forward.
         | 
         | At Worse: Get sued for breaking NDA, lose, pay a metric fuck
         | ton in damages, and get kicked out of the forum and can never
         | support HDMI products going forward.
        
           | amlib wrote:
           | What if _someone_ makes an unofficial patch with HDMI 2.1
           | support? You could at least compile your own damn kernel with
           | the damn thing supported.
        
             | Crosseye_Jack wrote:
             | If _someone_ released an unofficial patch for the official
             | OSS driver it might get by, it might get "DMCA'ed", though
             | DMCA might not be the correct takedown method for patent
             | violations (I'm just presuming this _someone_ released only
             | their own code and nothing from AMD, so AMD wouldn't have a
             | copyright claim over the code itself), but hey thats never
             | stopped companies mis-using the DMCA in the past! To file a
             | valid counter notice to a DMCA, that _someone_ would have
             | to give details which the forum could then use to sue the
             | publisher of the patch.
             | 
             | But yeah even if the patch some how was made public, and it
             | wasn't nuked out of orbit, ongoing support and bug fixes
             | would be a pain in the ass. (Because as an example, no one
             | from AMD would be allowed to touch the "patch code")
             | 
             | <edit> If AMD's planned patch was leaked for example, as
             | AMD had not officially released it, its not yet "open
             | source" and because of that, not yet public, and I'm sure
             | there will be a clause in the terms that state that AMD
             | would have to go on the offensive to get their code removed
             | from any public repos. </edit>
             | 
             | When it comes to lawfare, The Forum wouldn't have to be in
             | the right (in a legal sense), just have a big enough war
             | chest to make everyone else's life a pain in the ass!
        
         | rodgerd wrote:
         | "HDMI" is a trademark. You can't claim to offer HDMI in any of
         | your products.
         | 
         | The patent pools around approximately all the codecs used for
         | media delivery are heavily cross-licensed. That includes HDMI
         | and HDCP, but also h.264 and h.265. Most likely AMD can't
         | legally use hardware decoding or encoding of any popular codecs
         | at that point. Good luck with game video, streaming, or playing
         | media discs.
         | 
         | So it would cost AMD - for example - their entire
         | PlayStation/XBox business. At a minimum.
        
       | mikece wrote:
       | "Needless to say, open-source Linux advocates should try to use
       | DisplayPort instead if at all possible."
       | 
       | And at this point that's one of the several (many?) protocols
       | that runs over a USB-C cable, right?
        
         | conradev wrote:
         | DisplayPort is packet-based and can be multiplexed with other
         | USB-C traffic through a hub
         | 
         | HDMI is not packet-based and so when it uses USB-C it takes
         | over the entire cable (alt-mode)
        
           | baby_souffle wrote:
           | > DisplayPort is packet-based and can be multiplexed with
           | other USB-C traffic through a hub
           | 
           | This is part of why DP is $$$ compared to HDMI. I would love
           | to see DP start eating HDMI's lunch after this and the
           | absolute shit show that was the HDMI 2.0 roll out but cheaper
           | to implement is almost certainly going to be the driving
           | factor when it comes to consumer grade TV / Displays and no
           | console or other set top box maker is going to bother putting
           | display port on their device if nobody's got a TV that can
           | use it.
        
             | tverbeure wrote:
             | > This is part of why DP is $$$ compared to HDMI.
             | 
             | Why is that more expensive?
             | 
             | In terms of complexity, implementing DP vs HDMI 2.1 is not
             | materially different. They both have fixed rate links,
             | packets, Reed-Solomon forward error correction, DSC, etc.
             | 
             | But IIRC DP is royalty free, and HDMI is not.
        
               | refulgentis wrote:
               | It sounds like it might be more about "the market will
               | pay more for the packet-based approach, and we shall
               | charge what the market will bear"
        
               | tverbeure wrote:
               | Speaking about 'packet-based approach', the way it's
               | presented in the popular press as if it's similar to
               | Ethernet, is a pretty gross distortion, the impact of
               | which is not nearly as much as people seem to think it
               | is.
               | 
               | You can check that there in this presentation
               | (https://www.vesa.org/wp-content/uploads/2011/01/ICCE-
               | Present...), page 32 and 33.
               | 
               | The majority of DP traffic is still brute force video
               | data, interspersed with heavily packetized secondary
               | data.
               | 
               | Over the years, I've spent many hours wading through
               | DisplayPort data debug traces, and I've always wondered
               | what people were smoking when they called it 'packetized
               | like Ethernet'. It's just not true. (And FWIW: even old
               | HDMI can transport secondary data packets just the way
               | you can with DP. It's how audio-over-HDMI is done...)
        
             | babypuncher wrote:
             | It won't happen unless VESA gets serious about adding home
             | theater specific features to DP that HDMI has had for 20
             | years.
        
           | wolfhumble wrote:
           | > HDMI is not packet-based and so when it uses USB-C it takes
           | over the entire cable (alt-mode)
           | 
           | What does this exactly mean? I have an USB-C 4x1 Hub with
           | HDMI that works at the same time as using 2 x USB-A 3.0, 1 x
           | USB-C. Thanks!
        
             | izacus wrote:
             | It means that your hub uses DisplayPort to talk to the
             | computer and then has a converter chip to convert to HDMI.
             | 
             | Pretty much noone used HDMI Alt Mode on USB-C and is now
             | deprecated IIRC.
        
               | wolfhumble wrote:
               | Okay, thanks!
        
               | justsomehnguy wrote:
               | Reminds me of Ethernet over HDMI.
        
           | cesarb wrote:
           | > HDMI is not packet-based and so when it uses USB-C it takes
           | over the entire cable (alt-mode)
           | 
           | AFAIK, when HDMI is used over USB-C, it's actually
           | DisplayPort over USB-C; while a HDMI alt mode was specified,
           | nobody actually implemented it, everyone instead implemented
           | the DisplayPort alt mode and then used a DP-to-HDMI converter
           | chip whenever an HDMI output was required.
           | 
           | > DisplayPort is packet-based and can be multiplexed with
           | other USB-C traffic through a hub
           | 
           | That's the case only for USB4 (and AFAIK earlier Thunderbolt
           | 3). Other USB-C ports with DisplayPort alt mode simply use
           | some of the USB 3.x pairs for raw DisplayPort, and whenever
           | the use of all four USB 3.x pairs is required for DisplayPort
           | due to the target resolution, then only USB 2.x can be
           | available (USB 2.x has its own dedicated pair in the cable).
        
         | Cu3PO42 wrote:
         | Yes. You can run "DisplayPort Alt Mode" over USB-C. You can
         | also transport DP over Thunderbolt over USB-C.
         | 
         | HDMI Alt Mode also was a thing, but is now deprecated.
        
         | whalesalad wrote:
         | I am using a displayport to usb-c to connect an amd gpu to an
         | apple display and it works well.
        
         | TedDoesntTalk wrote:
         | You can run HDMI over ethernet CAT-6 cables, too.
        
         | gamepsys wrote:
         | You can run DP over USB-C. It's a use case they specifically
         | support. However, if you are the cutting edge you will be using
         | the actual DP cords. DP2.1 uses 80Gbit/s and Thunderbolt 3
         | USB-C is only 40 GBit/s. Once you start pushing high
         | resolutions (at least 4K) and high framrates the entire system
         | will be bottle necked by the cable. Top end displays are always
         | designed to take advantage of the latest DP port, and use the
         | entire bandwidth.
         | 
         | USB4 will push 120GBit/s. This will be enough for 8k 120hz/4k
         | 240hz but not much more. This will probably be enough for high
         | end consumer displays and GPUs for a decade out or so.
        
         | fuzzy2 wrote:
         | Actually, it is the only (display) protocol. HMDI Alt Mode,
         | while specified, never really manifested and is effectively
         | dead. DisplayPort is the only alternative and is more flexible
         | anyway.
         | 
         | Its packet-based nature is not relevant for DisplayPort Alt
         | Mode, by the way, because it gets dedicated pins. Sometimes
         | enough for two lanes, sometimes enough for four. It's
         | hilariously consumer-unfriendly. Only Thunderbolt leverages the
         | packet stuff and can transport up to eight lanes worth of
         | DisplayPort.
         | 
         | macOS does not support MST.
         | 
         | Who is supposed to get this? I don't know.
        
       | lucasyvas wrote:
       | This seems like a bigger deal that it looks like - this flat out
       | kills the legitimacy of HDMI in my mind. There's no reason to
       | keep it.
        
         | baq wrote:
         | You're right but I don't think tv manufacturers care.
        
           | lallysingh wrote:
           | There are lots of TV manufacturers to choose from,
           | thankfully.
        
             | olyjohn wrote:
             | Well if you find one that sells TVs with DisplayPorts, let
             | us know.
        
               | gorjusborg wrote:
               | With all the garbage that comes on TVs now, this is just
               | another reason to buy a monitor with an audio-out
               | instead.
        
             | Hamuko wrote:
             | How many TV manufacturers actually use DisplayPort?
        
             | whoopdedo wrote:
             | Are there? This seems to be one of those illusion of choice
             | industries where the different brands are only relabeling
             | of the same factory reference designs.
        
           | akira2501 wrote:
           | I remember when markets were considered through the will of
           | consumers. I miss those days.
        
         | riehwvfbk wrote:
         | HDCP
        
           | Cu3PO42 wrote:
           | DisplayPort supports HDCP.
        
             | riehwvfbk wrote:
             | In theory, but I think it's common for devices to only
             | enable it on HDMI ports.
        
       | SushiHippie wrote:
       | Is there any reason I'd want to use HDMI instead of DisplayPort?
        
         | alexsereno wrote:
         | Masochism
        
         | fnordpiglet wrote:
         | Your device doesn't have display port interfaces I guess. So
         | for instance if you have a raspberry pi, you're using HDMI one
         | way or another.
        
         | rodgerd wrote:
         | Good luck finding an AV receiver or TV with DisplayPort.
         | 
         | This pretty much locks any media players into proprietary
         | drivers.
        
           | Chabsff wrote:
           | DisplayPort to HDMI converters trivially solve that. Let the
           | TV consume HDMI all it wants while still "just" outputting DP
           | from the computer.
        
             | krs_ wrote:
             | Are there DP -> HDMI 2.1 adapters available that supports
             | 4k120hz with VRR and HDR? I've not seen any although I've
             | not looked too hard.
        
         | mianos wrote:
         | There are many more displays that support hdmi. It is a simpler
         | protocol. Display port is better and more modern, it's
         | packetised so the timing is not fixed by the source like udp.
         | HDMI is fixed timing and used to be much simpler hardware.
        
           | tverbeure wrote:
           | > HDMI is fixed timing and used to be much simpler hardware.
           | 
           | What do you mean by 'fixed timing'? The fact that the
           | transmission data rate is proportional to the pixel clock?
           | 
           | We're talking HDMI 2.1 here, which uses FRL (fixed rate link)
           | and thus has pixel clock decoupled from the pixel clock just
           | like for DP, with data split into packets. There's not a lot
           | of difference between DP and HDMI in terms of functionality
           | and complexity.
        
         | Tade0 wrote:
         | In some laptops the HDMI port is managed by the integrated GPU
         | and the DisplayPort by the discrete GPU, so ultimately it
         | affects which GPU you're using.
        
         | MegaDeKay wrote:
         | Taking a bit of a step back from your question, this Hackaday
         | article on why DisplayPort is so much better than HDMI from a
         | technical perspective is great.
         | 
         | https://hackaday.com/2023/07/11/displayport-a-better-video-i...
        
         | TedDoesntTalk wrote:
         | Does DisplayPort support audio?
        
           | izacus wrote:
           | Yes. (Although I'm not sure if it supports bitstreaming
           | formats like Dolby Digital, Atmos and DTS.)
        
           | betaby wrote:
           | It does.
        
           | adrian_b wrote:
           | Yes, it does.
           | 
           | I am writing this in Linux, while looking at a Dell monitor
           | connected through DisplayPort, and my loudspeakers are
           | connected to an audio output of the monitor.
        
         | Strom wrote:
         | If you want big resolutions and big refresh rates. For example
         | I have a 4K screen with 144 Hz refresh rate. That sort of
         | bandwidth can only be delivered right now via HDMI 2.1.
         | 
         | Yes there are DisplayPort standards that can reach that, but in
         | practice all the top end GPUs have only the old DisplayPort 1.4
         | version. That means the only choices are to use HDMI 2.1 or to
         | use video compression over DisplayPort 1.4.
         | 
         | I will say that VESA has been very successful with their
         | Display Stream Compression (DSC). Not that the algorithm is
         | something special, but in terms of marketing. You never see
         | monitor reviewers talk about the fact that using DSC will give
         | you artifacts. VESA markets this compression as visually
         | lossless, which every non-expert explains as actually lossless.
         | In reality the losslessness is defined in the standard as when
         | all the observers fail to correctly identify the reference
         | image more than 75% of the trials. Beyond that, like with any
         | compression, it will fail at high entropy images. Take for
         | example this 2017 study titled _Large Scale Subjective
         | Evaluation of Display Stream Compression_ [1] which found that
         | _performance on some images was not visually lossless, however,
         | those images were challenging images with high entropy_.
         | 
         | --
         | 
         | [1]
         | https://www.researchgate.net/publication/317425815_Large_Sca...
        
           | izacus wrote:
           | That's great, but have you actually seen those artifacts
           | ever?
           | 
           | (DSC also has a great property of making the image delivery
           | significantly more resilient to cable issues and thus much
           | more reliable for most people using high res monitors.)
        
             | Strom wrote:
             | > _That 's great, but have you actually seen those
             | artifacts ever?_
             | 
             | No, I use HDMI 2.1 without DSC.
             | 
             | Otherwise though, yes I have very good vision and work with
             | images professionally. I do spot artifacts when they are
             | there.
             | 
             | I get it that not everyone needs perfect images. I mean,
             | people watching YouTube certainly won't be able to tell if
             | there is an additional artifact on top of the low bitrate
             | video they're watching.
        
             | Sakos wrote:
             | DSC also has the great property of causing my RTX 3060 to
             | crash if I try to watch videos on an external monitor and
             | do the wrong thing on my main display. This issue has gone
             | unresolved for over a year now. HDMI, DSC and NVIDIA can go
             | eat a big bag of dicks.
        
           | zokier wrote:
           | [delayed]
        
         | thomastjeffery wrote:
         | Most displays that are marketed as a "TV" instead of a
         | "monitor" are exclusively HDMI. This is why many TVs from ~2020
         | don't have any 4K@120 input, despite actually displaying at
         | 4K@120 (from the internal GPU that does frame interpolation),
         | because HDMI 2.0 is limited to 4K@60.
        
       | Cu3PO42 wrote:
       | This is upsetting on principle alone. But I'm also upset because
       | I have my PC hooked up to my TV for couch gaming and was hoping
       | to do that on Linux sooner rather than later when HDR works
       | properly. I wasn't aware HDMI 2.1 was another problem... I guess
       | Windows is sticking around for that.
        
         | macNchz wrote:
         | FWIW I have my Linux desktop hooked up to a 4k/120hz TV via a
         | $30 CableMatters DisplayPort->HDMI dongle that seemingly
         | supports most of the relevant functionality, as far as I can
         | tell. It even works very smoothly over a 50 foot active fiber
         | optic HDMI cable. There is a ton of discussion about these
         | dongles in the issue thread linked in the article.
        
         | boomskats wrote:
         | HDMI 2.0 is capable of doing 4k @ 120Hz, but only up to YCbCr
         | 4:2:0 8bit instead of the full YCbCr 4:4:4 10bit (though I'm
         | not sure how close wayland is to 10bit support). It will be
         | fine for gaming, just not for everyday PC use.
         | 
         | FWIW I also didn't realise this until just now. I've been
         | running my desktop at 4k@120hz recently for the buttery smooth
         | neovide, but have been noticing that text rendering, especially
         | syntax-highlighted text, looks awful. I'd seen the same oled
         | panel render text way better in WSL/Windows (both using a
         | custom pixel geometry[0] via Mactype, but also without), so I
         | spent more time than I'm willing to admit to wrapping my head
         | around custom pixel layouts and hinting in freetype. But no,
         | turns out it was this all along.
         | 
         | If you want to see the effect of 420 vs 444 chroma subsampling
         | on text rendering, this writeup[1] has some great test images
         | and is well worth a read. Also, if you happen to have an LG
         | OLED panel, you can get a little debug window that confirms
         | your signal format and refresh rate, by pressing the green
         | button on the remote 7-8 times.
         | 
         | [0]: https://github.com/snowie2000/mactype/issues/720 [1]:
         | https://www.rtings.com/tv/learn/chroma-subsampling
        
       | Jun8 wrote:
       | For the longest time (like, the past 15 years) I've wanted a
       | cheap small box that can overlay custom info, eg text, on the TV.
       | The reason such a thing does not exist, other than projects like
       | Bunnie's NeTV (https://makezine.com/article/technology/review-
       | hardware-hack...) is that decoding HDMI signals is illegal if
       | you're not in the club. I think the ELI5 reason is that content
       | providers are afraid of unauthorized copying of DVDs (try taking
       | a screenshot of a frame from your DVD player on your laptop).
       | 
       | I'd be willing to pay up to $199 for such a box if it has an open
       | API to input overlay text and icons.
        
         | salawat wrote:
         | You are correct. Pay attention to the conspicuously lacking
         | feature. Odds are there's industrial collusion to keep it that
         | way.
        
         | refulgentis wrote:
         | It sounds like you've taken a deep long journey into the mess
         | here: I'm curious, what does it take to be a member of the
         | club?
         | 
         | I hope it's not just FAANGs and blessed hardware OEMs...but it
         | also sounds likely it must be, you can't let just anyone in if
         | you're worried about the specs leaking...but then again that
         | sounds weird too, in that, they used to provide the spec more
         | openly until 2.1?
        
           | metaphor wrote:
           | HDMI adopter registration details here[1]; in general, $10k
           | annual fee + royalties and of bunch of legalese. Prevailing
           | list of 2451 adopters and affiliates here[2]; yes, AMD
           | (listed as unabbreviated Advanced Micro Devices) has been a
           | registered Adopter since Aug 2006 and is currently listed as
           | a 2.1b licensee.
           | 
           | [1]https://www.hdmi.org/register/adopterregister
           | 
           | [2] https://www.hdmi.org/adopter/adoptersaffiliates
        
         | bombcar wrote:
         | You can get devices that "hack" HDMI to various other
         | unprotected signals such as SDI. So you get a Decimator or
         | something, covert HDMI to SDI, and then do the needful.
         | 
         | Now that may not help you, as the devices that do SDI overlays
         | run in the $1k range, but maybe something is out there like a
         | ATEM SDI https://www.blackmagicdesign.com/products/atemsdi
        
           | mschuster91 wrote:
           | Blackmagic's Mini Converters are at their core nothing more
           | than SerDes chips and an FPGA that does the protocol
           | translation. I _think_ that the recent models with USB-C
           | power supply inputs also have the data pins connected to the
           | FPGA.
           | 
           | Might be worth a try to check how hard BMD has locked down
           | the FPGA bitstream.
        
             | bombcar wrote:
             | I know the Decimators would remove HDCP, as it's a known
             | "trick" when trying to project from a Mac. But not sure
             | which versions, and how well.
        
         | goosedragons wrote:
         | Is there a reason a RPi or whatever with a cheap USB HDMI
         | capture card isn't a good option? I guess there might be a
         | minor quality loss but it should do what you want.
        
           | MenhirMike wrote:
           | HDCP usually is an issue if you can't turn it off on the
           | source. There are ways around that, though those are more
           | than $199 if you're dealing with an HDMI 2.x source.
        
             | 0cf8612b2e1e wrote:
             | I thought there were cheap converters that could go HDMI
             | 2->1?
        
             | treflop wrote:
             | I bought a HDMI 2.0 splitter that strips HDCP a while back
             | for $20.
        
         | thwarted wrote:
         | While reading your comment I was reminded of the much touted
         | key capabilities of the Video Toaster (late 80s), it's
         | character generator and chromakey, used to do exactly that:
         | overlaying text on video, for a fraction of the cost of what
         | professional video production cost. And now, 30+ years later,
         | we _still_ don 't have an accessible way to do that using
         | modern video tech/protocols, but now it's about rent seeking
         | and licencing rather than technical capability.
        
           | jethro_tell wrote:
           | That brings back some good memories. I had access to a video
           | toaster setup a couple days a week after school as well as
           | library checkouts of big vhs camera recorders. We'd get a
           | stack of tapes, do the 1 day rental of a camera and record
           | all over the neighborhood, then after school we'd take the
           | tapes in to the studio and mix them together.
           | 
           | All dumb shit, but you know we were kids.
        
           | wmf wrote:
           | There's tons of stuff out there. The ATEM Mini Pro can do
           | keying and a bunch more for $300.
           | 
           | In general, audio and video production have never been
           | cheaper or more accessible. There's no conspiracy of The Man
           | keeping people down.
        
         | sottol wrote:
         | I don't know if the ~$20 HDMI USB capture cards work on a
         | raspberry pi, but connecting one to a pi or laptop and
         | capturing the signal to a v4l stream, overlaying in software
         | and then outputting on built-in HDMI out might work?
        
         | dtx1 wrote:
         | I don't know about quality but I guess a Raspberry Pi, HDMI
         | Capture Card and OBS would do the trick and are within that
         | price range.
        
         | RobotToaster wrote:
         | There appears to be at least one open source HDMI
         | implementation https://github.com/hdl-util/hdmi
        
         | tim-- wrote:
         | From what I understand (and I could be _very_ wrong here) the
         | biggest issue here is simply the amount of memory that is
         | required in order to keep a copy of the current frame from a
         | HDMI signal, and the fact that to modify anything in the HDMI
         | signal, you need to decrypt (if watching a HDCP protected
         | stream), decode each frame, and then finally re-encrypt the
         | HDMI signal.
         | 
         | I was looking into what would be necessary to build a HDMI
         | switch that allowed for seamless switching of video between
         | different inputs, and basically there was no hardware for it.
         | The closest chips that I could find was Analog Devices' ADV7626
         | and Lattice's SiI9777S.
         | 
         | Lattice CP9777 might be worth having a look at if you can
         | understand anything about the datasheet :)
        
           | 4rt wrote:
           | As far as I can see there's no need to re-encrypt the signal
           | - just leave it as a non-HDCP stream?
           | 
           | There are HDMI splitters which silently strip HDCP to output
           | to two screens at once - they don't advertise this feature
           | but they do it anyway in order to function. In order to
           | achieve the overlay you'd just need one of these and then a
           | non-HDCP-aware overlay apparatus before the display.
           | 
           | https://www.reddit.com/r/VIDEOENGINEERING/comments/xme482/hd.
           | ..
        
           | mjevans wrote:
           | It would be a LOT more seamless if the output didn't have any
           | HDCP to re-synchronize. Though the different frame timings
           | (gen-lock is a term you want to search for) between the
           | inputs and outputs so such a system might introduce
           | presentation latency which would have to be accounted for in
           | the audio streams.
        
         | echohack5 wrote:
         | Maybe the closest thing to this is a Blackmagic box of some
         | sort. I use a the Ultrastudio 4K to capture 4K60 output, pipe
         | through OBS and pass through as well.
         | 
         | Will run you $1K though. Corsair/Elgato has some solutions in
         | your price range but the devil is in the details of precisely
         | what you're trying to accomplish.
        
         | justsomehnguy wrote:
         | There is a lot of answers here already, but I would remind
         | everyone, what if your target is _38-in-1_ DVD /HD/whatever to
         | resell for $5 the only thing you need is a $30 cam pointed at
         | the display.
         | 
         | Yes, it's not pixel perfect. Thing is, the people who buys
         | 38-in-1 _do not care_ about pixel perfect picture. They just
         | want an affordable way to spend an hour and half with their
         | family.
        
         | babypuncher wrote:
         | The really dumb thing is that nobody wants to copy DVDs or Blu-
         | Rays via HDMI anyways. It's much more convenient to decrypt the
         | discs directly with tools like MakeMKV.
         | 
         | However, I suspect that isn't the real holdup here since
         | DisplayPort also fully supports HDCP
        
         | ysleepy wrote:
         | Bunnie's work on HDMI mitm is really cool.
         | 
         | https://fahrplan.events.ccc.de/congress/2011/Fahrplan/events...
         | (Slides and long write up)
         | 
         | His 28C3 talk https://www.youtube.com/watch?v=37SBMyGoCAU
        
       | cultureulterior wrote:
       | Seems like you could have a separate shell organization that
       | built this functionality by looking at existing drivers, and just
       | provide the patch to the kernel.
        
       | betaby wrote:
       | Since, say France, has no software patents, can that work be done
       | in France and released thereafter? ( thinking of VLC example now
       | )
        
         | colordrops wrote:
         | Would probably involve retaliation outside of France if they
         | did this.
        
         | nextaccountic wrote:
         | I think that nouveau can do that. But AMD can't touch this code
         | because it is an US company
        
       | thomastjeffery wrote:
       | The HDMI forum ought to be subject to anti-trust action.
        
       | dusted wrote:
       | wow, hdmi really wants to die that badly ?
        
       | megous wrote:
       | Is this about the movie industry again?
        
       | coryfklein wrote:
       | Can AMD fork HDMI, add in driver support, and call it their own
       | standard that just so happens to be compatible with HDMI?
       | 
       | I'm sure they wouldn't make such a move lightly, but is there
       | something fundamental here about the laws or specifications that
       | prevents them from doing this?
        
         | dvdkon wrote:
         | I think they could, simply by IP laws, but they have a contract
         | with the HDMI Forum that probably doesn't allow that. They
         | could cancel it (and reverse-engineer HDMI instead of going by
         | the NDA'd spec), but I don't think they'd do that just for
         | Linux support.
        
       | nimish wrote:
       | Hopefully someone leaks the spec. Maybe it's already available?
       | 
       | Note that the latest VESA specs are also restricted.
       | 
       | FWIW, it's easily possible to sniff the control channel of an
       | HDMI or DP connection. At that point one could attempt to reverse
       | engineer the enabling features.
        
       ___________________________________________________________________
       (page generated 2024-02-28 23:00 UTC)