High quality video encoding in browsers have traditionally been slow, low-quality and did not allow much customisation. This is because browsers never had a native way to encode videos leveraging hardware acceleration. In this talk, I’ll be going over the secrets of creating high-quality videos in-browsers efficiently with the power of WebCodecs and WebAssembly. From video containers to muxing, audio and beyond, this talk will give you everything you need to render your videos in browsers today!