Fedora 37 includes a notable change which disables hardware acceleration for proprietary video codecs (most commonly H.264 and H.265) when using the Mesa drivers stack. Open video codecs (VP8, VP9, AV1 - based on your hardware capabilities) are unaffected and can still be hardware-accelerated out of the box.
This change mainly affects AMD graphics cards. (Intel GPUs don’t use Mesa for video acceleration, Nvidia cards use the proprietary driver, and Mesa video acceleration mostly doesn’t work properly with the opensource Nouveau driver).
The patent licensing around H.264/H.265 is such that providing the acceleration support further could unfortunately leave Red Hat and other Fedora distributors exposed to legal problems.
You can read more about this problem in this discussion on the devel list.
It is possible to install Mesa video acceleration libraries with full support including proprietary video codecs from RPM Fusion. The specific instructions (after enabling the repository) are in the Multimedia howto in the Hardware Accelerated Codec section (rpm-ostree systems have specific instructions here).
WARNING: These codecs from RPMFusion can get desynchronized when there’s a major Mesa update in Fedora. This can lead to system crashes when playing videos or even an inability to start your graphical session. For this reason, it’s currently not recommended to use this approach. It can very easily destabilize your system.
Please note that RPM Fusion is not supported by Fedora and using software from it might violate software patents, depending on where you live.
You can discuss this topic here.