BTR AMP
ALAC (Apple Lossless Audio Codec) is Apple's lossless format — open-source since 2011, stored in .m4a containers, and the format iTunes has always used for lossless rips.
Why the built-in Music app isn't enough
The Music app plays ALAC natively — the friction is everything around playback. Its navigation is fixed however your collection is organized, tags cannot be edited on the device, large libraries slow it down, and an ALAC collection ends up walled off from the FLAC, DSD, or OGG files most serious collections also contain. If your lossless library is split between Apple formats and everything else, you end up running two players or converting one half.
How BTR AMP plays ALAC
BTR AMP plays ALAC in one library with FLAC, AIFF, DSD, and every other supported format — including your existing iTunes library side by side with non-iTunes files. Hi-res ALAC plays at up to 96kHz/24-bit and beyond, at full resolution through a USB DAC, and every track shows its exact codec details. The on-device editor covers MP4/iTunes tags — the metadata ALAC files carry — plus cover art and star ratings, and custom tabs and smart playlists keep 50,000+ tracks navigable.
Getting your ALAC files onto your iPhone
ALAC files transfer like any other format.
Send files over Wi-Fi from any browser on your computer (Connect → Wi-Fi Transfer), pull them from Google Drive, OneDrive, iCloud Drive, an SMB share, or WebDAV, use AirDrop, or play straight from a USB drive. The transfer guide walks through each method, and the importing guide covers the details.