Apple’s HomePod, Files in iOS, and QuickTime Player in macOS all support FLAC audio playback. However, iTunes still does not support the FLAC format, which makes it more difficult users to use the high-quality file format.
The support for FLAC files in the HomePod was tucked away in the tail-end of the supported audio formats technical data. It is unclear why the format is supported by Apple unless they are planning to also add support to iTunes.
FLAC files can now be played back in QuickTime Player in macOS. However, other players like VLC handle the files better, with other niceties that aren’t in QuickTime Player available.
Audio sources encoded to FLAC are typically reduced to 50 percent of their original size on a CD, depending on the characteristics of the track and some encoding settings. Apple’s lossless ALAC format is similar in audio quality, but not as widely supported by third parties as FLAC.
Apple’s first moves to support FLAC were in iOS 11. Early beta versions added the ability to play back single tracks encoded in FLAC format in the Files app, using the standard media player.