Unable to fix black screen live stream in Safari on Mac mini

I'm having problem with live stream video in Safari on Mac mini M4.

Trying to watch live stream of Czech television channels (ČT sport – Česká televize), but there is black screen, and audio only. Same with app iVysilani.

All other footage except live stream is OK. In MS Edge browser everything work OK. Safari on iPhone or iPad works also OK. The only problem is Safari on Mac mini M4 with latest macOS.

What could be wrong with safari?

[Re-Titled by Moderator]

Original Title: black screen live stream in safari