A video denoising method includes: while continuing to receive a video stream, performing multi-stage denoising processing on a respective frame, including: detecting a change in a current network status of a network connection; and, in response to detecting the change in the current network status: adjusting a current value for a predefine flatness threshold for detecting a flat area within the respective frame of the image stream in accordance with the change in the current network status of the network connection; identifying one or more flat areas within the respective image frame in accordance with the predefined flatness threshold; and performing, using a predefined filter, denoising processing on the one or more flat areas that have been identified in accordance with the predefined flatness threshold.