.mp4 video playback issues on Quicktime and Safari on MacBook Pro M1

Playing mp4 videos in QuickTime causes my MacBook Pro (14" 2021, M1, Sonoma 14.4..1) to freeze up; audio continues but mouse pointer disappears, the computer becomes unresponsive while audio continues to play, and after failed attempts to force quit the QuickTime program, a hard restart is required. Video quality does not matter, having tried both 1080 and regular HD versions of the video. Unfortunately, playing the same videos on Safari through Vimeo gives the same results, audio continues while the mouse pointer disappears and the machine becomes unresponsive, again requiring a hard restart. What is needed to resolve this issue?