| Feature | ALAC | FLAC |
|---|
| Developer | Apple Inc. (open-sourced 2011) | Xiph.org Foundation |
| License | Apache 2.0 | BSD/GPL |
| Compression | ~50-60% of PCM | ~50-60% of PCM |
| Container | M4A (MP4) | Native FLAC or Ogg |
| Max bit depth | 32-bit | 32-bit |
| Max sample rate | 384 kHz | 655,350 Hz |
| Max channels | 8 | 8 |
| Metadata | iTunes-style (MP4 atoms) | Vorbis Comments |
| Album art | Embedded (MP4 standard) | Embedded (FLAC PICTURE block) |
| ReplayGain | Via iTunes Sound Check | Native tag support |
| Streaming | Apple Music, AirPlay | Tidal, Deezer, web |
| Seeking | Fast (MP4 index) | Fast (seek table) |
| Error resilience | Per-frame (MP4 structure) | Per-frame CRC |
Both codecs achieve virtually identical compression ratios. In tests across diverse music genres:
| Genre | ALAC Size | FLAC Size | Difference |
|---|
| Classical (orchestral) | 61% of WAV | 59% of WAV | FLAC 2% smaller |
| Rock/Pop | 58% of WAV | 57% of WAV | FLAC 1% smaller |
| Electronic | 52% of WAV | 51% of WAV | FLAC 1% smaller |
| Jazz | 60% of WAV | 58% of WAV | FLAC 2% smaller |
| Speech/Podcast | 42% of WAV | 40% of WAV | FLAC 2% smaller |
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.
This is where the formats diverge significantly:
- 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
- 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.
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 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).
Since both formats are lossless, converting between them preserves perfect audio quality:
ffmpeg -i input.flac -c:a alac -c:v copy output.m4a
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.
- 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
- 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)
- 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.
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.
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.
