mp3worker

Web Worker to decode MP3 files

Why?

Web Audio includes support for decoding audio via decodeAudioData(); however, this doesn't work for all formats on all operating systems.

In our case, MP3 files failed to decode on the following configurations:

1. Opera on Windows Vista and Windows 7 (possibly others)
2. Firefox on Linux
3. Various Android devices (including all Kindle Fire tablets)

To solve this, we compiled lieff's minimp3 project with Emscripten and added a small abstraction layer. Previous versions of mp3worker used Martin J. Fiedler's minimp3 project.

The source directory contains a small Xcode project used to build the first abstraction layer. From there:

1. We ran emcc -Oz --memory-init-file 0 -s WASM=0 -s EXPORTED_FUNCTIONS=_mp3_init,_mp3_decode mp3worker.c
2. We copied a portion of a.out.js into mp3worker.js
3. We added an additional abstraction layer for a cleaner interface

Usage

See example in index.html.

License

mp3worker.js and all files are dedicated to the public domain.

/*
 * mp3worker
 * https://github.com/musictheory/mp3worker/
 *
 * Based on minimp3
 * https://github.com/lieff/minimp3
 *
 * Dedicated to the public domain
 * https://creativecommons.org/publicdomain/zero/1.0/
  */