MP3 to chords
Drop an MP3 and read the chord progression back. Nothing is uploaded: your browser decodes the file and the analysis runs on this device.
What happens to an MP3 here
MP3 is lossy, and the first thing it throws away is high-frequency detail. That sounds like it should hurt chord detection, but it does not: chord identity lives in the fundamentals and the first few harmonics, and EarChord only reads the band between 55 Hz and 2 kHz. The parts of the signal an MP3 encoder discards are mostly above that.
Bitrate barely matters for the same reason. A 128 kbps file and a 320 kbps master of the same track usually produce the same chord list. What does matter is how busy the mix is: dense guitars, heavy reverb and loud cymbals all put energy into pitch classes that no instrument is actually playing.
Getting a better read
If a section comes back wrong, trim the file to that section and run it again. A short excerpt of one part gives cleaner pitch-class evidence than a whole track whose arrangement changes underneath it.
Live recordings, phone recordings and heavily compressed loudness-war masters are the hard cases. An intro or a verse with fewer instruments will read more reliably than a final chorus.
Questions
- Is there a file size limit?
- No fixed limit. The file is held in your browser tab, so the practical ceiling is your device memory. Full-length albums in one file are the only thing that tends to struggle.
- Does the MP3 get uploaded anywhere?
- No. There is no upload step at all. The audio is decoded by your browser and analysed in a Web Worker on your machine.
- How many songs can I run?
- As many as you want. There is no daily limit and no account, because analysing your file costs us nothing.