HDMI licensing

[Berni]

It's questionable. Inexpensive adaptors are simply level shifters. DP output needs to generate HDMI signal anyway. Google DP++ or Displayport dual-mode.

Well it still needs at least conversion, so without having an adapter cable the DisplayPort device is not capable of outputting HDMI. Even if it can reproduce the correct timings, it can't reproduce correct voltage levels so it can't be called HDMI. Just like you can't invent a USB bus with 5V data lines and still call it USB.

Also the dual mode feature is not a mandatory feature for all DisplayPort devices. So you can simply chose to implement a version of DP that does not support such simple adapters. In that case you don't even generate any timings similar to HDMI. All the signals you output are pure DisplayPort, so the entirety of the HDMI signal must be generated inside the adapter cable. For all your device knows there might be an active DP to VGA adapter on that cable.

The interface standard consortium usually are more concerned about what you stick the logo onto. For example anyone can create a USB 1.0 low speed device by just bitbanging data out of a MCU. You can even sell this device and the USB consortium won't come knocking on your door. The thing you are not allowed to do is use the copyrighted logos on your device without there approval (aka pay the licensing fee).

[jonpaul]

To Omega: "depressing that standards like HDMI aren't open and free to use"

The standards organizations eg IEC, IEEE, AES, etc take considerable time and cost to create and maintain them.

Manufactures and compliant users pay the small fess to get the genuine and up to date standards.

If you spent years to write a book, movie script or compose music, and that is your profession, would you give it all away?

Enjoy,

Jon

[wraper]

Also the dual mode feature is not a mandatory feature for all DisplayPort devices. So you can simply chose to implement a version of DP that does not support such simple adapters. In that case you don't even generate any timings similar to HDMI. All the signals you output are pure DisplayPort, so the entirety of the HDMI signal must be generated inside the adapter cable. For all your device knows there might be an active DP to VGA adapter on that cable.

Active adapters are quite expensive though. Like $15+ for junk from China.

[NiHaoMike]

Well it still needs at least conversion, so without having an adapter cable the DisplayPort device is not capable of outputting HDMI. Even if it can reproduce the correct timings, it can't reproduce correct voltage levels so it can't be called HDMI. Just like you can't invent a USB bus with 5V data lines and still call it USB.

Also the dual mode feature is not a mandatory feature for all DisplayPort devices. So you can simply chose to implement a version of DP that does not support such simple adapters. In that case you don't even generate any timings similar to HDMI. All the signals you output are pure DisplayPort, so the entirety of the HDMI signal must be generated inside the adapter cable. For all your device knows there might be an active DP to VGA adapter on that cable.

More to it, you could have the factory firmware only enable the pure DP modes and a "community maintained" firmware that also enables the HDMI compatible modes.

[Hydron]

To Omega: "depressing that standards like HDMI aren't open and free to use"

The standards organizations eg IEC, IEEE, AES, etc take considerable time and cost to create and maintain them.

Manufactures and compliant users pay the small fess to get the genuine and up to date standards.

If you spent years to write a book, movie script or compose music, and that is your profession, would you give it all away?

Enjoy,

Jon

Except that the fees to access standards are only small for larger companies selling many products. Small players are forced to pay the same price for a small fraction of the use that larger ones will get out of it, sometimes even being forced to buy a "pack" of standards at a crippling kilo$s price just to legally own a single necessary one. There really should be a better way other than piracy that doesn't f**k the little guys. IMHO this should extend down to $free for trivial/hobby/research users - if you're trying to recoup costs charge the serious $ to sellers of millions of devices.

[Berni]

Yeah standards are way too expensive.

But still they generally won't come after you unless you infringe on there trademarked logos. Often to play it safe when mentioning the names like HDMI USB SD...etc there is a asterisk footnote mentioning that such and such is a trademark of company X.

Luckily once a standard becomes popular you can find some sort of spec online with enough digging.

What is worse is that things like CE approval list out a requirement to pass some listed out standards. Yet you have to actually buy these standards to read what they require. So they make it a law that selling electronics on a whole continent requires adherence to a piece of paper that you need to buy to see what says on it. Aren't laws supposed to be publicly available so that anyone can read them and make sure they are not doing something wrong? Surely someone as big as the EU could buy the publication rights to those standards and post them up publicly on there own website.

[Hydron]

If you ever find yourself needing an EN standard, then go have a look at the Estonian standards body page - they have their own re-branded (literally calls out what EN standard it is copied from) versions of most of them, at a FAR lower price than many other European sources will charge. Many also let you view them for a day for something like 2EUR (handy if you need to just check a single thing - printscreen doesn't get disabled  )

[VEGETA]

the point is that IC manufacturers refuse to sell you their HDMI ICs unless you have a license.

 

[Just_another_Dave]

Yeah standards are way too expensive.

But still they generally won't come after you unless you infringe on there trademarked logos. Often to play it safe when mentioning the names like HDMI USB SD...etc there is a asterisk footnote mentioning that such and such is a trademark of company X.

Luckily once a standard becomes popular you can find some sort of spec online with enough digging.

What is worse is that things like CE approval list out a requirement to pass some listed out standards. Yet you have to actually buy these standards to read what they require. So they make it a law that selling electronics on a whole continent requires adherence to a piece of paper that you need to buy to see what says on it. Aren't laws supposed to be publicly available so that anyone can read them and make sure they are not doing something wrong? Surely someone as big as the EU could buy the publication rights to those standards and post them up publicly on there own website.

In some countries they are available at university libraries (at some public libraries they might also have them) and, in the case of Spain, at your local guild (although in this case they are just available for members). Additionally, the standards bodies of some countries offer yearly subscriptions to access all of them online for a smaller price of a single one in pdf (and they notify you if the ones you’re using get updated). They also sell books with a simplified version of a set of related standards for a reasonable price

[usagi]

the point is that IC manufacturers refuse to sell you their HDMI ICs unless you have a license.

basically HDMI is hostile to the hobbyist and eevblog community.

displayport has no such limitations.

wish dave would make a video about this. more people need to be aware of this.

[usagi]

To Omega: "depressing that standards like HDMI aren't open and free to use"

The standards organizations eg IEC, IEEE, AES, etc take considerable time and cost to create and maintain them.

Manufactures and compliant users pay the small fess to get the genuine and up to date standards.

If you spent years to write a book, movie script or compose music, and that is your profession, would you give it all away?

Enjoy,

Jon

you want a world where PNG, WAV, and IPv4 is licensed. i really don't like this world you envision.

[Berni]

Adobe went the closed license route for PDF.

But of course like any format once it got popular people started to reverse engineer the format. This caused cheap/free PDF software to pop up, so people used it for making PDF documents. However the reverse engineering was not quite perfect, so some of these PDF files would not open correctly in the official Adobe PDF reader while they would open perfectly fine in a reader using the reverse engineered spec. So it was starting to make there product look bad and eventually they made the spec available to avoid the PDF format becoming incompatible with itself.

So sometimes hiding the spec can come back to haunt you.

[magic]

Not gonna happen to HDMI due to patents. But you can try

[Just_another_Dave]

Adobe went the closed license route for PDF.

But of course like any format once it got popular people started to reverse engineer the format. This caused cheap/free PDF software to pop up, so people used it for making PDF documents. However the reverse engineering was not quite perfect, so some of these PDF files would not open correctly in the official Adobe PDF reader while they would open perfectly fine in a reader using the reverse engineered spec. So it was starting to make there product look bad and eventually they made the spec available to avoid the PDF format becoming incompatible with itself.

So sometimes hiding the spec can come back to haunt you.

PDF is in fact ISO standardized (probably to fulfill the requirement that some countries have of using standardized formats if possible instead of closed ones). Its standard is available here: https://www.iso.org/standard/75839.html

[wraper]

PDF is in fact ISO standardized (probably to fulfill the requirement that some countries have of using standardized formats if possible instead of closed ones). Its standard is available here: https://www.iso.org/standard/75839.html

And became such only 15 years after its release.

[ebastler]

basically HDMI is hostile to the hobbyist and eevblog community.

With reference to hobbyists, which limitations and hostility are you thinking of specifically?

I have certainly used HDMI in a few hobby projects: Open-source FPGA cores, HDMI jacks, and driver ICs (if I want to use them) are freely available. And so far I have not received a cease-and-desist order for calling the interface on my boards "HDMI" -- and in my understanding I am free to call it that, since the trademark does not interfere with personal/non-commercial use.

[Zero999]

PDF is in fact ISO standardized (probably to fulfill the requirement that some countries have of using standardized formats if possible instead of closed ones). Its standard is available here: https://www.iso.org/standard/75839.html

And became such only 15 years after its release.

There's still a problem with editable documents. M$ Turd has often been used, but the problem with that is, apart from being propriatory, it often falls over when opened in a different version. M$ tried to rectify that with .docx format, but it still isn't perfect. LibreOffice tends to do better at displaying properly in different versions, but isn't 100% compatible with M$.

[Berni]

There's still a problem with editable documents. M$ Turd has often been used, but the problem with that is, apart from being propriatory, it often falls over when opened in a different version. M$ tried to rectify that with .docx format, but it still isn't perfect. LibreOffice tends to do better at displaying properly in different versions, but isn't 100% compatible with M$.

Yeah MS Word documents have the exact same problem where other people built compatible editors from the reverse engineered spec, but are again not quite entirely compatible with the real thing.

Tho this case is likely at least in part due to legacy baggage. The format is pretty old and they kept adding features in every version of Office, so it likely has bugs in it that have been worked around in certain ways, so in order to perfectly reproducibly render the word document you also must perfectly reproduce the subtle bugs that help make the document render correctly in the official Microsoft Word. At this point its likely that even if Microsoft wanted to write an official spec on how to correctly generate a Word document, they most likely could not because nobody there knows all of the intricate details and nuances of how the format works.

This sort of format bloat can quickly happen if people are allowed to just glue on features onto a format without someone moderating it all and making sure all the additions fit in with everything else nicely. Something that could have easily happened as the MS Office team gets turned around multiple times to a point where the guy who came up with the format is no longer there.