I Tried Running File Conversion Fully in the Browser (WASM, LibreOffice, FFmpeg)

Intro – The Problem Most online file converters work the same way: you upload your file, wait, then download the result. That raises privacy concerns and doubles transfer time for large files (upload + download = double the time). Personal context: I'm an audio producer and needed to convert some legacy audio formats for a project. I tried 5 different converter sites but none of them supported the formats I needed - or hit me with endless pop-ups and CAPTCHA walls. The whole experience felt quite sketchy and so I thought: there has to be a better way. Turns out: there is – but it's not as simple as I thought. I wondered: how much of this can realistically run in the browser? Turns out: more than I expected, but with hard limits nobody talks about. The LibreOffice WASM Dream (That Didn't Work) My first idea: compile LibreOffice headless to WebAssembly. It's the Swiss Army knife for document conversion (DOCX, ODT, PDF, PPTX...). If I could get it running in the browser, I'd be done. Real