"What is the point of having an HDMI 2.1 standard at all?"
Good question. It turns out that HDMI is not a 'standard', in the same way as we understand standards, such as PCIe data lanes on PCs, IEEE Ethernet and similar. Here is what they say:
Testing Policies - HDMI
HDMI.org is only a licensing agent to administer licensing of HDMI Specification, promote HDMI technology and provide 'education' on the benefits of HDMI interface. I found this extract:
"Successful completion of the Compliance Test Specification or ATC Testing
does not guarantee that any product will conform to the High-Definition Multimedia Interfaces, function correctly or interoperate with any other product. Each Adopter is solely responsible for ensuring that its products function correctly, fully comply with the HDMI Specification and Adopter Agreement, and interoperate with other products." It does not sound reassuring, does it? Is this another reason why we are in such a mess now with HDMI 2.1?
HDMI seems to be
a lose list of features written as a non-mandatory specification and owned by a trade association of consumer electronic companies, rather than
being 'industry standard', like IEEE Ethernet or PCIe are. Hence, the rigour of interoperability of HDMI products entering the market could be lower. Manufacturers can release products with mismatched features, products that have not been tested with other products and simply hope those products are going to work together. It seems that compliance certification is not enough to give consumers confidence when new tech spec appears, as certification sticker does not guarantee that devices would work together. We all know what happened to Yamaha and Sound United AVRs in 2020...
The question is whether any institution, including court of law, could enforce on HDMI association to introduce:
1. interoperability testing as mandatory prior to product market release
2. make HDMI 2.1 a real standard with minimal mandatory features rather than all being optional
That would tighten things
Standard, specification, is it not the same thing?
It turns out that those two thigns are not the same. There is a relationship between them, but it is important to differentiate between them. HDMI has never been a standard.
Specification is simply a list of features in something, such as XL T-shirt size or HDMI 2.1 features. In order for a specification to become a
standard, all parties implementing it must understand it the same way. For example, if USA has different chart for XL T-shirt or shoe size than in Europe, you will get two different sizes of the same specification. 'XL T-shirt size' becomes a standard only if everyone globally produces it to the same metric or royal units.
Standard requires uniformity of features, whereas specification simply lists features.
The same applies to tech specs. Hence the mess we are in now. Adopters have too much freedom to pick and choose whichever feature from HDMI specification to support. Some support full speed, some limited speed, some support VRR and ALLM, some other features too. It is not a standard, as soon as you can pick and choose.
Certification means that an adopter has built ports and chips to
chosen features from the spec and this has been checked and stamped. Certification does not guarantee standardization, i.e. the same operational experience across devices. If that was the case, repeater chips in 2020 AVRs would have worked well with the chip in Xbox SX and would not produce black screen. Manufacturers did not sit down to agree which features to bake into chips, so that entire chain operates under one AV pipeline umbrella named "HDMI 2.1". Each manufacturer simply chose features they thought would work. Also, some features are more important then others. Now that HDMI 2.1 does not require any minimal mandatory features, it is even worse.
HDMI 2.1 spec is like a recipe for chip choc cookies, paraphrasing Phil Shea from Yamaha. Each household knows the recipe, but once ingredients are mixed and baked, those cookies could have different flavours and shapes. So, the recipe is an instruction only, not a standard, and certification allows you to have a sticker 'choc chip cookie' on your or my bake, but our cookies could still taste differently, i.e. they are not standardised.
Even their advice to look for specific features is meaningless, as the same feature can be delivered in different ways. For example, someone needs 4K/120 source, AVR and display. Now, "4K/120" is still quite vague and it says nothing about supported port speeds.
1. Is it "4K/120" 8-bit 4-2-0 that I need (HDMI 2.0 TMDS 18 Gbps)?
2. Is it "4K/120" 10-bit 4-2-0 that I need (HDMI 2.1 FRL3 20 Gbps)?
3. Is it "4K/120" 10-bit RGB that I need (HDMI 2.1 FRL5 40 Gbps)? etc.
HDMI org does not provide this level of scrutiny and standardisation at the moment, apart from cables, as the companies that this body represents are currently not willing to self-regulate more and adopt HDMI as formal standard. Hence this utter mess and anti-consumer practices. Only court of law can force them to become a standard everyone could understand. Putting HDMI 2.1 in an advert has become completely meaningless and some groups should organise a class law suit action against those practices. It's untenable to behave like this in consumer market.
