What music player do you use on your PC? How do you share/sync your ratings with your phone/car-audio/mp3-player/tablet/other device? Do you use ReiserFS4/ZFS -

What music player do you use on your PC? How do you share/sync your ratings with your phone/car-audio/mp3-player/tablet/other device? Do you use ReiserFS4/ZFS - or what's the fetish with file hashes about? Mac/iOS or music streaming (Spotify, etc.) service walled garden eco-system? There are several metadata formats for mp3, flac, mp4, etc. formats. Windows Media Player e.g. stores the music star rating per user name and adheres to the metadata standard. Most media player apps adhere to the metadata standards. Some players only read, but write to an internal database with no export option - I burnt myself with iTunes back in 2004. Some apps write older metadata formats like IDv1 instead of v1 and v2. If you mean CRC32/MD5/SHA1-hash, than you do something wrong. There are special hashes for music data like qhash and minhash that Google and other similar services use. The media formats like mp3 have seperate sections for the audio data and the metadata payload, so you should use a hash of only the audio data anyway, the metadata is meant to be edited (parts of it as described in the standards). Only with mp3 files that contain proper metadata one can sync his audio with various devices from different manufacturers.