ALAC vs FLAC: Apple Lossless vs Free Lossless

Two Lossless Formats, One Purpose

ALAC (Apple Lossless Audio Codec) and FLAC (Free Lossless Audio Codec) both achieve the same fundamental goal: compress audio without losing a single bit of data. Decompress either format and you get an exact, bit-perfect copy of the original PCM audio. No information is discarded, no quality is lost — they are mathematically identical to the source.

So why do two formats exist? The answer is ecosystem politics. FLAC was created in 2001 by Josh Coalson as an open-source, patent-free lossless codec. Apple developed ALAC in 2004 as part of iTunes and initially kept it proprietary, before open-sourcing the reference implementation in 2011. Each format became the default lossless option within its respective ecosystem — FLAC for Android, Linux, and general-purpose use; ALAC for Apple devices, iTunes, and Apple Music.

If you are choosing between the two for your music library, the decision comes down to your device ecosystem and software preferences, not audio quality — because the quality is identical.

Head-to-Head Comparison

Compression Efficiency

Both codecs achieve virtually identical compression ratios. In tests across diverse music genres:

FLAC is consistently 1-3% more efficient than ALAC. On a 1000-album library, this difference amounts to about 2-5 GB — noticeable but not decisive.

FLAC also offers configurable compression levels (0-8), where higher levels trade encoding speed for smaller files. ALAC has no such configuration — it uses a single, fixed compression algorithm.

Device and Platform Support

This is where the formats diverge significantly:

ALAC Support

• iPhone, iPad, Mac, Apple Watch, HomePod — native
• Apple Music — lossless streaming in ALAC
• iTunes / Music app — native
• AirPlay — native lossless transmission
• Android — supported via most third-party players
• Windows — supported via iTunes, foobar2000, VLC
• Linux — supported via VLC, ffplay
• Car stereos — some (typically Apple CarPlay)
• Web browsers — none native

FLAC Support

• Android — native since Android 3.1
• Windows — native since Windows 10
• Linux — universal native support
• Tidal, Deezer, Amazon Music — lossless streaming in FLAC
• VLC, foobar2000, MusicBee — native
• iPhone/iPad — NO native support (requires third-party apps)
• Mac Music app — NO native support
• AirPlay — not supported (transcodes to AAC)
• Web browsers — partial (Chrome, Firefox)

The critical difference: iPhones and iPads do not play FLAC natively. If you use Apple devices, ALAC is the path of least resistance. If you use Android or PCs, FLAC has broader native support.

Metadata and Tagging

ALAC (MP4 atoms)

ALAC uses the MP4/M4A metadata system, which is the same tag format used by AAC files from the iTunes Store. Tags include:

• Standard fields: title, artist, album, genre, year, track/disc number
• Album artwork: embedded as JPEG or PNG
• iTunes-specific: grouping, compilation flag, sort fields, gapless info
• Sound Check: Apple's volume normalization

FLAC (Vorbis Comments)

FLAC uses Vorbis Comments, a flexible key=value tag system:

• Standard fields: TITLE, ARTIST, ALBUM, GENRE, DATE, TRACKNUMBER
• Album artwork: PICTURE block (JPEG or PNG, multiple sizes)
• ReplayGain: REPLAYGAIN_TRACK_GAIN, REPLAYGAIN_ALBUM_GAIN
• Custom tags: any key=value pair

Both systems handle standard music metadata well. FLAC's Vorbis Comments are more flexible (arbitrary custom tags), while ALAC's MP4 atoms integrate better with the Apple ecosystem (sort fields, Sound Check).

Converting Between Formats

Since both formats are lossless, converting between them preserves perfect audio quality:

FLAC to ALAC

ffmpeg -i input.flac -c:a alac -c:v copy output.m4a

ALAC to FLAC

ffmpeg -i input.m4a -c:a flac -compression_level 8 output.flac

Both conversions are lossless — the decoded PCM is re-encoded without any information loss. Metadata may need manual verification, as some tags do not have direct equivalents between Vorbis Comments and MP4 atoms.

For batch conversion between lossless formats, see our batch processing guide.

Which Should You Choose?

Choose ALAC if:

• Your primary devices are iPhone, iPad, and Mac
• You use Apple Music for streaming
• You use AirPlay for home audio
• Your car stereo works with Apple CarPlay
• You want seamless integration with the Apple ecosystem

Choose FLAC if:

• Your primary devices are Android phones and Windows PCs
• You use Tidal, Deezer, or Amazon Music for streaming
• You use a dedicated audio player (DAP) like FiiO or Astell&Kern
• You want the broadest compatibility outside Apple
• You prefer open-source formats on principle
• You want maximum compression efficiency (marginally better than ALAC)

Choose Both if:

• You have a mixed ecosystem (iPhone + Windows PC, or Mac + Android tablet)
• Store your master library in FLAC (slightly smaller, more flexible)
• Convert to ALAC for Apple devices as needed (lossless conversion)

For a broader comparison of audio formats, see our FLAC vs MP3 guide and our WAV vs FLAC comparison.

The Practical Reality

In 2026, the ALAC vs. FLAC debate is less heated than it used to be. Apple Music streams in ALAC, while most other services stream in FLAC — but the actual audio your ears receive is identical. Both formats decode to the same PCM data. The only differences are file size (negligible), metadata conventions (manageable), and device support (the real deciding factor).

If you maintain a personal lossless library, pick the format that your primary playback devices support natively. If you ever switch ecosystems, converting between ALAC and FLAC is a lossless operation — no quality penalty whatsoever.

Conclusion

ALAC and FLAC are both excellent lossless audio formats that deliver identical audio quality. ALAC is the clear choice for Apple-centric workflows, while FLAC dominates everywhere else. The 1-3% compression advantage of FLAC is real but rarely decisive. Choose based on your device ecosystem, not on technical merit — both formats do their job perfectly.

Need to convert? Try our free Audio Converter to convert between ALAC, FLAC, and other formats — no registration required.