Compliant HDMI shouldn't introduce any latency itself. It's just a digital signal, no different in principle than the signal from a wired game controller. Where

Compliant HDMI shouldn't introduce any latency itself. It's just a digital signal, no different in principle than the signal from a wired game controller. Where latency can creep in is a TV's image processing algorithms – a color adjustment algorithm might add a few milliseconds, an edge enhancement might add a few more; a 120hz motion compensation system will add a lot more. Most TVs will allow these to be disabled (often in a specifically labeled "game mode") but a few may inexplicably not allow them all to be disabled, hardwired for a certain degree of latency. AirPlay, on the other hand, introduces a lot of latency because it's compressing the image prior to transport and uncompressing it on the other end. This generally introduces significantly more lag than any TV image processing.