HDMI Musings: high speed cables, data rates, YCbCr color subsampling, Dolby Vision MEL/FEL, optical cables and +5V injection.

Hey folks, for this post, I thought it would be good to dive a little more into the world of AV technologies after discussing the nVidia Shield TV Pro last week. While "classic" audiophile technology (ie. standard hi-fi analog and digital 2-channel stereo without special DSP advancements) has matured nicely already, this isn't quite the case with modern digital video tech. While many (probably most) features have settled, we can see ongoing evolution of the High-Definition Multimedia Interface (HDMI) standard to be mindful of - for example the recent announcement of HDMI 2.2 at CES2025 expanding capabilities well beyond the needs of today.

As usual, it'll take time (years) for this standard to be incorporated into TVs and source devices like GPUs (latest nVidia RTX 5080/5090 are HDMI 2.1b) or something like VR devices being at the forefront of potential generational gains. For more than 20 years, with each significant revision of the HDMI standard, we're seeing doubling of data speed with HDMI 2.2 now aiming at just shy of 100 gigabits-per-second (96Gbps), twice of the 48Gbps bit rate in current HDMI 2.1 products.

This recent update makes HDMI the fastest of all currently-announced consumer Audio-Video connection standards, the one wire that basically does it all - hi-res video (with high dynamic and frame rate), hi-res audio (up to 32 PCM channels at 24/192, with DSD to 8-channel of DSD256), HDCP copy protection, audio return channel, even ethernet (100Mbps).

This level of sophistication (and licensing costs) could make it difficult for small companies with limited R&D capabilities to get in the game with custom designs. This is probably in part why the cottage industry audiophile companies rarely use HDMI other than selling overprices cables (like AudioQuest). Plus frankly, basic 2-channel audio doesn't need the higher technical capabilities anyway (which is basically what Paul McGowan says).

Let's run through a few thoughts about HDMI that might be good to know as general knowledge as tech enthusiasts. I'll provide a few links of interest, touch on tech stuff like color spaces and subsampling, and things you might want to try if you're running longer high-speed HDMI connections and potentially noticing issues.

MUSINGS: Zen and the Art of High Fidelity Audio. On transparency, in response to "Measuring Emotional Connections to Music".

Man, once surrendering his reason, has no remaining guard against absurdities, the most monstrous, and like a ship without a rudder is the sport of every wind. With such persons, gullibility takes the helm from the hand of reason, and the mind becomes a wreck.     --Thomas Jefferson

I ran into this article on Inner Fidelity: "Measuring emotional connections to music" penned by Rafe Arnott & Vinnie Rossi the other week that got me thinking about the hobby and the different "sensibilities" of those who partake and who write.

As you know, recently, I measured and discussed the sound of the Oppo UDP-205 player/DAC. I said that the device is "transparent". I believe that this is an important aspect to focus on because it touches right at the heart of the ideas and philosophies expressed in the article. Today, let's explore the themes brought out in that article a bit. As you can imagine, I come at audio from another perspective compared to Mr. Arnott and Rossi.