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MP3 Compressor

A bulk audio compressor that runs entirely in your browser. No uploads, no account, no limits.

Next.jsTypeScriptffmpeg.wasmWebAssembly
Try it ↗GitHub ↗
The MP3 Compressor page: a drop zone for audio files, a target space saving slider at 50% (about 128 kbps), and a Compress All button.
Drop in files, pick how much space to save, compress.
About

What it does

I needed to shrink my music to fit on a smartwatch, and every free online converter came with an account or a limit. So I built one.

It uses ffmpeg compiled to WebAssembly, so all encoding happens locally in the tab. Drop in MP3, WAV, M4A, FLAC, OGG or AAC files, pick how much space to save on a slider that maps to a bitrate from 320 down to 32 kbps, and download them one by one or as a zip. A pool of four ffmpeg instances encodes files in parallel.

  • +Nothing leaves your machine
  • +Four files encode at once
  • +Bulk download as a zip
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