ALLM

Allm, or Auto Low Latency Mode, is a feature defined in the HDMI standard that allows a video source to request a display to switch into a low-latency processing path automatically. The goal is to minimize input lag for interactive content, such as video games, by reducing or bypassing certain image-processing steps.

How it works: When a source device supports Allm and the display supports it as well, the source can signal that it needs low latency. The display may then enable a predefined low-latency mode, often by bypassing or shortening post-processing like motion smoothing, aggressive noise reduction, or color grading. The exact behavior depends on the manufacturer and the display’s firmware. In many setups, enabling Allm happens transparently if HDMI-CEC and all participating devices negotiate the capability correctly; in others, users may need to enable a related setting such as a game mode or Allm in the display’s menu.

Adoption and scope: Allm is part of the HDMI Forum specifications associated with HDMI 2.1 and is supported by a wide range of modern TVs, monitors, and AV devices. It is commonly used with game consoles, streaming devices, and PCs that output through HDMI. While it is designed to improve responsiveness, its availability varies by model and firmware, and not all sources or displays implement it identically.

Limitations: Allm’s effectiveness depends on compatible hardware and proper negotiation. Some displays may reduce image quality in low-latency modes, or the mode may not activate reliably in all input configurations. Utilities and settings can also differ between manufacturers.

See also: HDMI, HDMI 2.1, game mode, input lag, HDMI-CEC.