You can support a variety of formats in Safari using WebAssembly builds of the decoders. WebAssembly for audio and image formats is more than fast enough. It's even fast enough for VP9 video.
WebP demo: https://webmproject.github.io/libwebp-demo/webp_wasm/index.h...
Theora\VP8\VP9\Opus\Vorbis demo: https://brionv.com/misc/ogv.js/demo/
ogv.js on GitHub: https://github.com/brion/ogv.js