Convert AAC to WebM — Free Online Converter

AAC is the dominant audio codec in the Apple and MPEG ecosystem, while WebM is Google's open multimedia container designed for the web, pairing VP8/VP9 video with Vorbis or Opus audio. Converting AAC to WebM transcodes the audio to Opus (the modern default) or Vorbis and wraps it in the WebM container, producing files optimized for web delivery via HTML5 video and audio elements.

WebM is the native media format for Chromium-based browsers, Firefox, and the open web. While Safari added WebM support recently, WebM remains the most efficient format for web delivery, especially with Opus audio which surpasses AAC in quality-per-bit at every bitrate. Google services (YouTube internal processing, Google Meet, WebRTC) use WebM/Opus extensively.