If you’re using the USB-C port to connect your computer to a display, you’re most likely using DisplayPort Alternate Mode (Alt Mode), and you can pretty much guarantee it isn’t because it’s not adopted. increase. HDMI Alt mode. According to the HDMI Licensing Administrator (HDMI LA), this feature has been deprecated, so you should never need to.
HDMI Alt Mode allows you to send an HDMI video signal from the USB-C port to an HDMI host such as a TV. This is similar to DisplayPort Alt Mode, which allows you to connect a DisplayPort display to your USB-C port. NotebookCheck spoke with HDMI LA, who is responsible for licensing his HDMI specification for the HDMI Forum last week at CES 2023 in Las Vegas, and over USB he said that there are no certified adapters that support HDMI Alt Mode. I found out
“According to HDMI LA there is no more use for Alt mode,” the magazine reported Wednesday. “One reason is that companies like Apple have started putting HDMI ports back into their products. “
losing battle
HDMI’s announcement comes at a time when USB-C relentlessly dominates a variety of consumer gadgets. Manufacturers of thin and light laptops like the Dell XPS 13 and experimental designs like foldable PCs are increasingly running out of room for anything but slim, space-saving USB-C. From laptops to smartphones, there are many products that rely solely on USB-C (and wireless technology) for all their accessories and even power delivery.
That means a lot of people will find themselves connecting displays via USB. Instead, it’s just using her Alt mode of DisplayPort.
Released in 2014, DisplayPort Alt Mode has a head start over the HDMI Forum’s announcement of HDMI Alt Mode in 2016. This technology can also support HDMI 2.0.
HDMI Alt Mode feels dated as it maxes out at HDMI 1.4b. The HDMI LA page on HDMI Alt Mode addresses the lack of HDMI 2.0 support, pointing out that the HDMI Forum is responsible for the HDMI specification and has not made an official statement about HDMI Alt Mode supporting HDMI 2.0b. I’m here. No mention of the new HDMI specification.
HDMI over Alt mode supports HDMI features such as Audio Return Channel, HDMI Ethernet Channel, Appliance Control, Deep Color, xvColor. HDMI forum confirmed that it is used to connect PCs, tablets and phones to displays such as TVs, monitors and projectors. Ultimately, however, it could not compete with DisplayPort’s Alt mode, which could support higher refresh rate HDMI displays (e.g. 4K vs. 30 fps at uncompressed 60 fps). The latest version of DisplayPort Alt Mode can also support 24-bit color, but HDMI takes are limited to 8-bit. The latest USB standard, USB4, does not support HDMI Alt Mode.
The HDMI specification makers envisioned HDMI Alt Mode being used in cables, adapters, and various gadgets.
These higher specs help explain why so many products, from USB-C ports on laptops to myriad HDMI-to-USB-C adapters and cables, have opted for DisplayPort Alt mode.
In fact, HDMI LA has confirmed to NotebookCheck that it does not recognize HDMI to USB-C adapters that use HDMI Alt mode. NotebookCheck also spoke with people “familiar with the certification process” on the USB Implementers forum, but they said they didn’t know about his HDMI Alt Mode adapter either.
In some ways this makes things easier. As NotebookCheck points out, the removal of HDMI Alt Mode means that HDMI adapters will work reliably with your system as long as you have a USB-C port that supports DisplayPort Alt Mode.
There is currently a certification program for HDMI to USB-C cables and a certification program for USB-C to HDMI adapters is underway so that you can purchase the correct adapter for your HDMI port. His DisplayPort-based HDMI-to-USB adapter has “basic certification,” but this isn’t obvious to consumers, he points out to NotebookCheck.
