Apple Music will apparently stream music at a lower bitrate than rivals, though it will maintain the same quality that customers already expect from iTunes.
Apple Music will apparently stream its music at 256kbps. This is the same rate that is currently available from the iTunes Store for both download and streaming. However, it is a lower maximum bitrate than what is offered by rival services like Spotify and Rdio, which offer a maximum bitrate of 320kbps. Even Beats Music, the service being replaced by Apple Music, lets users stream and download music at 320kbps.
Apple Music will be at 256 kbps. In comparison, Beats Music uses a 320 kbps bitrate, as does Spotify, while Tidal offers a high-bitrate option.
While some might find this disappointing, it's not that surprising. Apple has often taken a conservative approach when adopting new formats. Even on services that offer 320kbps streaming, that quality is not always available for all tracks. It could be that Apple hopes to offer a consistent experience, opting for the lower bitrate. What's more, they might not be seeing enough demand for quality higher than 256kbps.
Songs were originally available on the iTunes Store at 128kbps. When the company announced DRM-free tracks in 2009, the quality was increased to 256kbps. No word yet on the format that Apple Music will use, though it seems likely to be AAC, the same format found on the iTunes Store.
If that's the case, then it's possible the AAC format might offset some or most of the difference in compression.