This page allows you to check if a given codec is supported in your browser. Given the wide variety of codecs, it is sometimes difficult to know in advance if a codec will be supported. This page shows test results using the Audio/VideoEncoder.isConfigSupported() for both hardware-accelerated and software encoding.
You can check General MIME Types, General track codecs, Audio codecs and Video codecs, in particular all AVC profiles, AV1 profiles or other video codecs such as VP9, HEVC or test your own codec.
The code for this page is hosted on GitHub here. If you see any mistake, please file an issue or submit a pull request.