According to Joe Belfiore, Microsoft's Operating Systems Group vice president, Windows 10 for phones and small tablets will support FLAC, a popular lossless audio compression format. Belfiore said FLAC support will arrive on smaller Windows 10 devices a few months after the initial preview build, which is due in the next month or so.
Microsoft had already announced system-wide FLAC support for Windows 10 last year, showing a screenshot of FLAC files loaded in Windows Media Player. But Windows 10 will be somewhat different on screens less than 8 inches, lacking a desktop and support for Win32 applications. Those limitations won't have any effect on FLAC support, apparently.
FLAC is the format of choice for high-quality music vendors such as HDTracks, and is popular for sharing audience-recorded live music. Because no data is lost to compression, it can be repeatedly burned to and from CDs or converted to other lossless formats like WAV without any loss in audio quality.
It's worth noting that in response to Belfiore's tweet, several users asked about gapless playback, which eliminates the pauses between locally-stored audio tracks. This capability is notoriously absent from Windows Phone 8.1, but so far there's no word on whether it's coming to Windows 10.
Why this matters: FLAC support on mobile devices would have been of limited use a few years ago, when phones with 8 GB flash drives were more common than 64 GB ones, but it's starting to make more sense as capacity increases. And while it's certainly a niche feature, it could be a killer one for music lovers, especially when paired with the expanded music sync capabilities coming to OneDrive.