When uploading music to streaming services, you can use these file types: WAV, MP3, M4A, FLAC, or AIFF.
If you’re submitting a WAV file, the standard format is 16-bit, 44.1 kHz, though most other variations are also accepted.
The largest file size eMastered allows is 1 GB per track. If your song is bigger than that, it’s best to convert it to FLAC before uploading. FLAC maintains the same sound quality as WAV but produces a much smaller file.
There are also length restrictions:
Each track must be under 1 hours (60 minutes).
The combined runtime of all songs on an album must be no more than 10 hours (600 minutes).
Albums cannot include songs with an average track length shorter than 60 seconds.