Embodiments of systems and methods for video encoding acceleration in virtual, augmented, and mixed reality (xR) applications are described. In an illustrative, non-limiting embodiment, an Information Handling System (IHS) may include a processor; and a memory coupled to the processor, the memory having program instructions stored thereon that, upon execution by the processor, cause the IHS to: receive sensor data from a Head-Mounted Device (HMD) wearable by a user during execution of an xR application, where the sensor data indicates movement of the HMD; modify the sensor data into a motion hint; and provide the motion hint to a video encoder, where the video encoder is configured to use the motion hint to accelerate encoding of video transmitted by the IHS to the HMD during execution of the xR application.