ALL VIDEO TOOLS23
MP4 to MP3
Extract Audio from MP4 — Convert to MP3 Online
Pull the audio track out of an MP4, WebM, MOV, AVI or MKV and download it as an MP3.
About MP4 to MP3
Want just the audio from a video? There are many situations where the audio track is all you need — extracting background music from a video, saving the audio from a lecture or conference talk for listening on the go, pulling the soundtrack from a movie trailer, converting a video podcast to an audio-only format for your podcast player, or saving the narration from a tutorial. Upload your MP4, WebM, MOV, AVI, or MKV file and extract the audio track as an MP3 file with your preferred bitrate. Choose from 128 kbps for spoken word content and smaller files, 192 kbps for a good balance, or 256-320 kbps for music where quality matters most. The tool uses FFmpeg.wasm to decode the video container and encode the audio stream, running entirely in your browser via WebAssembly. No video files are uploaded to any server, ensuring complete privacy for personal recordings, copyrighted content, and confidential meeting recordings. The extraction process focuses on the audio stream, so even very large video files produce compact MP3 output.
Questions
What bitrate should I choose?
128 kbps is fine for speech and podcasts. 192 kbps is a good balance for music. 256-320 kbps provides near-transparent quality for audiophiles.
Can I extract audio from non-MP4 videos?
Yes! Despite the name, this tool accepts MP4, WebM, MOV, AVI, and MKV files. Any video with an audio track can be converted to MP3.
What if the video has no audio?
FFmpeg will report an error if there is no audio stream to extract. Make sure your video file contains an audio track.
Is there a maximum video size?
No. The video is read in place rather than copied into memory, so only the much smaller MP3 output has to fit in the tab — extraction from a 2.5 GB file has been verified end to end. That's why this tool has no cap, while the tools that build a full-size copy of the video in the tab — the trimmer, the container converters, the muter and the rotator — all stop at 1.5 GB.
How long does extraction take?
About a minute per 600 MB of video: the video track is skipped entirely, but the audio still has to be decoded and re-encoded to MP3 in single-threaded WebAssembly. In testing, a 400 MB file took around 40 seconds and a 2.5 GB file just over four minutes.
Is my file uploaded to a server?
No. Transmute processes everything locally in your browser using JavaScript and WebAssembly. Your files never leave your device — there is no server, no upload, no cloud processing.