The USB-CEC Adapter supports a maximum HDMI bandwidth of 4K@60Hz 4:2:0 in-line. This is a hardware limitation of the current adapter. Content or displays requiring higher bandwidth — such as 4K@120Hz, 8K, or high-bitrate HDR — cannot reliably pass through the adapter when it is connected in the signal path between your PC and TV.
Resolution and Format Support
| Signal / Format | In-Line Support | Cable Required |
|---|---|---|
| 1080p (Full HD) | ✓ Fully supported | Standard HDMI |
| 4K@30Hz | ✓ Fully supported | High Speed HDMI (18Gbps) |
| 4K@60Hz 4:2:0 | ✓ Fully supported | High Speed HDMI (18Gbps) |
| 4K@60Hz 4:4:4 / HDR | ✓ Generally reliable | High Speed HDMI (18Gbps) |
| 4K@120Hz | ✗ Not supported in-line | Use two-cable workaround — see below |
| 8K | ✗ Not supported in-line | Use two-cable workaround — see below |
| Dolby Atmos (TrueHD / high-bitrate) | ✗ Unreliable in-line | Use two-cable workaround — see below |
The total cable length from your source through the adapter to your TV should not exceed 2 metres. Longer runs increase the chance of signal issues even within the supported resolution range.
Using the Adapter With 4K@120Hz or High-Bandwidth Content
If your display or content exceeds the adapter's bandwidth limit, connect the adapter to a spare HDMI port on your TV instead of in the main signal path. Your TV responds to CEC commands from any HDMI port — the adapter does not have to carry your video and audio signal to control the TV.
- Connect your PC directly to your TV's primary HDMI port using your main HDMI cable. This carries your full 4K@120Hz or HDR signal with no adapter in the way.
- Connect the USB-CEC Adapter via a short HDMI cable (under 2 metres) to any spare HDMI port on your TV. Nothing needs to play through this port.
- In CEC-Tray, open the Configuration tab and set the HDMI port number to match the port the adapter is connected to. If using cec-client, add
-p Xto your commands where X is the port number.
For full step-by-step instructions, see: CEC Adapter — 4K@120Hz, HDR, and Signal Issues at High Resolutions
Related Articles
- CEC Adapter — 4K@120Hz, HDR, and Signal Issues at High Resolutions
- CEC Adapter — Dolby Atmos and High-Bandwidth Audio
- Getting Started with the Pulse-Eight USB-CEC Adapter
Not sure if your setup is supported?
Contact Pulse-Eight support with your TV model, GPU, and the resolution you are trying to run and we will advise.
UK: 01202 413 610 | US: (858) 748-8250 | support@pulse-eight.com
Contact Pulse-Eight support with your TV model, GPU, and the resolution you are trying to run and we will advise.
UK: 01202 413 610 | US: (858) 748-8250 | support@pulse-eight.com