I have a HEVC video that I'm trying to watch. It downloads to Quick time but freezes a couple seconds in.

I have a Mac running macOS Sonoma 14.5. I'm trying to watch a short video that was sent to me in HEVC format. I downloaded to QT. It starts to play but freezes a couple seconds in. If I try to watch it on my 14Pro running iOS 17.5.1, it freezes on the screen but can see video running below. I can select a frame to watch at a time but need to see the video in a larger window.