Handle unsupported codecs

[ilian]

Some MPEG-4 profiles are not supported on every platform, such as h264 (High 10) on Firefox for Windows 11.
We could prompt the user to install the required codec or use a different browser.
Alternatively, we could transcode the media file with ffmpeg but this likely leads to a degraded user-experience since transcoding is highly cpu-intensive, especially on lower-end devices.