Firefox brings smooth video playback with the fastest AV1 decoder
Among these is the high performance, royalty free AV1 video decoder dav1d, now enabled by default on all desktop platforms (Windows, OSX and Linux) for both 32-bit and 64-bit systems. Now that desktop Firefox contains dav1d, we expect even more websites will take advantage of this next-generation, royalty-free video codec AV1. State-of-the-art decoders like dav1d are great for video playback, but best-in-class, free and open source software encoders are equally important to a healthy AV1 community.
Source: hacks.mozilla.org