One of the big changes on the 3rd-gen Fire TV Cube, compared to the last two models, is the addition of an HDMI IN port on the back that lets you connect any HDMI device to the new Cube. Amazon hasn’t said much about the new port, other than saying it’s for cable and satellite TV boxes. In reality, you can plug any HDMI device into it. Here is everything about how the port works with the Fire TV Cube and what you can do with a device connected to it.
As mentioned, you can connect any HDMI device to the Fire TV Cube’s HDMI IN port, not just cable boxes. All HDMI devices, whether they be a cable box, game console, Blu-ray player, computer, OTA tuner, or other streaming box/stick, will essentially behave the same way. For the purposes of this article, I’ve connected a Nintendo Switch game console, but just substitute whatever HDMI device you use often and everything I describe will work the same way.
Of course, once you have an HDMI device connected to the HDMI IN port of the Fire TV Cube, you can switch from the Fire TV interface to that HDMI device at will. This can be done by saying “Alexa, switch to HDMI,” to either the Cube or the remote mic, or you can use the input menu in the Fire TV’s main navigation bar, located between the profile icon and the search icon. When you have the “HDMI” icon highlighted in the input menu, a live feed of the connected HDMI device with audio passing through is displayed in the top right corner. I wish the Fire TV’s interface shadow didn’t cover so much of the lower-left preview video because you could literally just use the HDMI device from this preview without switching to it if you wanted to, as if it were a picture-in-picture display.
The other way to switch to the HDMI IN device is to just wake it up, assuming it supports HDMI-CEC power controls, because the Fire TV Cube does support HDMI-CEC capabilities through the HDMI IN port. So if the connected device is HDMI-CEC compatible, which most modern HDMI devices are, just using the device’s remote will cause the Fire TV Cube to automatically switch to it. Even if the TV is off and the Fire TV Cube is asleep, if you wake the HDMI device connected to the Cube’s HDMI IN port, the Cube will wake up, then wake up the TV, and then switch to the HDMI IN device. This leads to the Fire TV Cube’s next HDMI IN capability, which is controlling the connected HDMI device using the Fire TV Cube’s remote.
If the device connected to the HDMI IN port of the Fire TV Cube can be controlled over HDMI-CEC, then you’ll be able to control it using the Fire TV Cube’s remote. For example, if you have a Google/Android TV streaming device connected to the Cube’s HDMI IN, you can use the Fire TV Cube’s remote navigation ring, select, play/pause, fast-forward, and rewind buttons to control the Google/Android TV device. You can even use voice commands, like “Alexa, Play” or “Alexa, scroll down” to control the connected HDMI IN device, since even those basic voice commands are passed through HDMI-CEC to the connected device. It is quite trippy to be using Alexa to scroll in a Chromecast app, that’s for sure, but it’s very cool that it works so well. For cable/satellite boxes, and possibly other HDMI devices, you can use the channel up/down buttons on the Fire TV remote to channel surf on the set-top box, which explains why Amazon included its Smart TV remote with the Cube instead of the usual Fire TV remote.
So you can seamlessly switch between your Fire TV Cube and your HDMI IN device and you can control the HDMI IN device with the Fire TV Remote, but the capabilities don’t end there. With the HDMI IN device being viewed, you still have full access to Alexa and all of the voice assistant’s usual Fire TV overlays. Issuing a hands-free Alexa command or pressing the mic button on the remote will display Alexa’s blue listening bar on top of the HDMI IN device being viewed. You’ll hear Alexa’s response come out of the built-in speaker in the Fire TV Cube.
If you issue an Alexa command that displays a full-screen result, like searching for a restaurant, you can just press the back button when you’re done and you’ll be right back to the HDMI IN device without skipping a beat. Even better is if you issue a command that uses one of the newer compact Alexa displays, like asking for the weather or asking a factual question. Those Alexa interactions pop up right on top of the HDMI IN device without taking you away at all.
While watching the HDMI IN device, you can say “Alexa, preview my [CAMERA NAME]” and a picture-in-picture feed of your camera will be displayed over the HDMI IN device. From there, you can press and hold the home button on the Fire TV remote to enlarge or dismiss the camera feed, or you can use voice commands to do the same. The Fire TV Cube is capable of automatically displaying the PIP video feed of compatible smart video doorbells when someone is at your door. I assume that the PIP popup would also be automatically displayed over the HDMI IN video as well, but I don’t have a compatible doorbell to test it myself.
Basically, anything that can be overlayed on top of the Fire TV interface can also be overlayed on top of the HDMI IN device. Above is everything I could think to activate simultaneously, being displayed over a Nintendo Switch connected to the Fire TV Cube’s HDMI IN port. You’d obviously never actually display all of that at once, but it demonstrates the Fire TV Cube’s ability to overlay information and features on the HDMIN IN device.
As for the technical capabilities of the HDMI IN port, it’s limited to the same 4K @ 60Hz video that the Fire TV Cube is limited to. So if you connect something like an Xbox Series X or PS5, you will not be able to pass 120Hz video through the Fire TV Cube or be able to use VRR. (Huge thanks to AFTVnews reader Beau Taylor for testing that for me!) However, the HDMI IN port of the Fire TV Cube can pass Dolby Vision and HDR10 video just fine. I assume HDR10+ video will also pass through fine, but I couldn’t test that.
By default, the Fire TV Cube will upscale or downscale all video coming into the HDMI IN port to match the output resolution that your Fire TV Cube is set to. So, for example, if the Cube is connected to a 4K TV and set to output in 4K and you connected a Nintendo Switch (which is only capable of 1080p) to the HDMI IN port of the Cube, the Cube will upscale the Switch to 4K and the TV will indicate that the Switch video is in 4K. As far as I can tell, the Fire TV Cube is not using its new “Super Resolution” upscaling feature to do this, since turning the feature on or off seems to make no difference to the upscaled HDMI IN video. The benefit of allowing the Fire TV Cube to upscale/downscale HDMI IN video, as needed, is that your TV then doesn’t need to switch between resolutions each time you switch between the Fire TV interface and an HDMI IN device with a different output resolution. Resolution switching, especially on older or cheaper TVs, often results in a jarring black screen being flashed each time, so letting the Cube upscale/downscale video will void that.
If you prefer that the Fire TV Cube does not upscale/downscale any HDMI IN video, you can switch an option called “HDMI Input Passthrough” from OFF to ON in the Fire TV Cube display settings. Turning this option on will force the Fire TV Cube to match the resolution of the HDMI IN device when switching to it and then switch back to the Fire TV Cube’s own resolution setting when you switch back to using the Fire TV interface. With the Cube set to 4K, I did find that the Nintendo Switch’s 1080p video was slightly crisper when the Fire TV Cube was not set to upscale its HDMI IN video, but this came at the expense of screen flashes every time I went in and out of the HDMI IN video. For me, the image quality difference wasn’t noticeable enough to not let the Cube upscale the video feed, but better TVs with better built-in upscaling may result in a more noticeable difference.
The 3rd-gen Fire TV Cube does a great job of making its HDMI IN port much more than just a 1-port HDMI switch. Essentially, it allows you to treat a separate HDMI device as if it were just another app running on your Fire TV. It’s very seamless to jump between the Fire TV interface and the HDMI IN device, much more so than asking Alexa to switch TV inputs or using your TV’s remote to switch inputs. This is made even easier with the “Recent” button on the Fire TV Cube’s remote since “HDMI” appears in the recent app list as well. If your HDMI device supports HDMI-CEC control, the experience is even better because you can use the Fire TV Cube’s remote to control the HDMI device and even use basic Alexa voice commands to control it. All of that and you also get to retain the convenience of on-screen Alexa capabilities while using the HDMI IN device. It all works so well that it makes me wish there were more than one HDMI IN port on the Fire TV Cube.