ALAC vs M4A
A detailed comparison of Apple Lossless Audio and M4A Audio — file size, quality, compatibility, and which format to choose for your workflow.
Technical Specifications
| Specification | .ALAC | .M4A |
|---|---|---|
| MIME type | audio/mp4 (inside .m4a) | audio/mp4 |
| Extensions | .m4a (common), .alac | — |
| Container | ISO Base Media File Format (like MP4) | ISO Base Media File Format (ISOBMFF) |
| Sample rates | Up to 384 kHz (hi-res); typical 44.1-192 kHz | — |
| License | Apache 2.0 (since 2011) | — |
| Extension | — | .m4a (and .m4b for audiobooks, .m4p for legacy DRM) |
| Codecs | — | AAC-LC, HE-AAC, ALAC |
| Max sample rate | — | 96 kHz |
Strengths Comparison
.ALAC Strengths
- Lossless — bit-exact with the original PCM.
- 40-60% smaller than uncompressed WAV/AIFF.
- Native Apple ecosystem support (iTunes, Apple Music Lossless).
- Open-source since 2011 — supported in FFmpeg, VLC, Android.
.M4A Strengths
- Superior audio quality to MP3 at the same bitrate (AAC codec).
- Native support across Apple, iOS, Android, and Windows.
- Carries rich metadata: album art, chapters, lyrics, podcast bookmarks.
- Same container as MP4 — tooling overlaps with video workflows.
- Lossless variant (ALAC inside M4A) for audiophile archiving.
Limitations
.ALAC — Limitations
- Non-Apple devices support ALAC but rarely make it the default.
- Slower encoding than FLAC on most reference implementations.
- Large files vs lossy alternatives (AAC).
- The .m4a extension is shared with lossy AAC, causing mislabeling.
.M4A — Limitations
- AAC patents still active in some jurisdictions — licensing fees apply for encoders.
- Seeking in variable-bitrate M4As can drift without an index atom.
- Less universal than MP3 on older hardware (pre-2010 car stereos, cheap MP3 players).
- Container overhead is larger than a raw ADTS AAC stream.
Frequently Asked Questions
ALAC (Apple Lossless Audio) is an audio file format used to store sound recordings — music, voice, podcasts, sound effects. The format defines how the audio samples are compressed (or stored raw), what bitrates are supported, and how metadata such as title, artist, album, and cover art is embedded. It is part of the audio files family.
M4A (MPEG-4 Audio) is an audio-only variant of the MP4 container, popularized by Apple in 2004 with the iTunes Store. Inside the .m4a wrapper is typically AAC (lossy) or Apple Lossless (ALAC) audio. The same container holds video when renamed .mp4 — only the track contents differ.
VLC, foobar2000, and the default media players on Windows and macOS handle ALAC natively. On mobile, iOS Music and Android media apps vary in their support — popular formats work everywhere; niche ones may need a dedicated app. If playback fails on a device, converting to MP3 or AAC usually solves it.
M4A files play on every Apple device natively, Windows Media Player, VLC, foobar2000, and most modern media players. Android supports M4A since version 2.0. On older car stereos and MP3 players, convert M4A to MP3 first — KaijuConverter does this in one click.
Upload the ALAC to KaijuConverter and pick MP3, WAV, FLAC, AAC, OGG, or any other target. Our FFmpeg pipeline decodes the audio and re-encodes to the target format at sensible default bitrates (VBR ~190 kbps for music, 96 kbps for speech). Metadata and cover art travel with the audio where both formats support them.
ALAC can be lossy or lossless depending on the specific variant. Lossy variants (smaller files) discard some audio detail during compression in ways tuned to be inaudible; lossless variants preserve every sample exactly but produce larger files. For distribution, lossy at high bitrate is standard; for archival, lossless wins.
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