MP4 to MP3 Converter

Why extract MP3 from MP4?

MP4 is a video container — great for movies and clips, but oversized when all you want is the soundtrack. MP3 is the universally compatible audio format that plays in every car stereo, podcast app, music player, and editing tool on the planet. Pulling the audio out of an MP4 gives you a file that's a fraction of the size and works everywhere.

Common use cases: saving a lecture as an audio file, ripping the soundtrack from a music video, capturing a podcast episode from a video recording, or prepping clips for a DJ set.

How browser-based extraction works

Morphix runs FFmpeg compiled to WebAssembly directly in your browser tab. When you drop an MP4, the file is read into memory, FFmpeg demuxes the audio stream from the video container, and re-encodes it as an MP3 you can download. The whole pipeline happens locally — your video never leaves your device, and there's no upload progress bar because there's nothing to upload.

Privacy & speed advantages

• Private: nothing uploads, nothing logs, nothing leaves your machine
• Fast: no upload/download round trip — extraction speed is limited by your CPU, not your internet
• Unlimited: no file-size cap, no batch cap, no daily quota
• Offline: works without an internet connection after the page loads once
• No watermarks, no signup, no ads in your output