ALAC vs OPUS
A detailed comparison of Apple Lossless Audio and Opus Audio — file size, quality, compatibility, and which format to choose for your workflow.
Apple Lossless Audio
Audio FilesALAC (Apple Lossless Audio Codec) provides lossless compression for audio, similar to FLAC but native to Apple ecosystem.
About ALAC filesOpus Audio
Audio FilesOpus is a versatile, open-source audio codec optimized for both speech and music at very low bitrates. It is the standard for WebRTC voice calls and excels at real-time communication.
About OPUS filesStrengths 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.
OPUS Strengths
- Best-in-class quality across the entire bitrate range.
- Royalty-free and patent-free.
- Ultra-low latency — suitable for live voice and music.
- Handles speech and music equally well — no need to switch codecs.
- Mandatory codec in WebRTC, so supported in every browser by design.
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.
OPUS Limitations
- Very low hardware decoder adoption — software-only on most phones.
- Older platforms (legacy Windows apps, old cars) may not play .opus files.
- Container semantics confusing — Opus lives inside Ogg, WebM, or MP4.
- Encoder tooling is less polished than AAC's commercial ecosystem.
Technical Specifications
| Specification | ALAC | OPUS |
|---|---|---|
| MIME type | audio/mp4 (inside .m4a) | audio/opus |
| Extensions | .m4a (common), .alac | .opus, .ogg (container) |
| Container | ISO Base Media File Format (like MP4) | — |
| Sample rates | Up to 384 kHz (hi-res); typical 44.1-192 kHz | 8, 12, 16, 24, 48 kHz |
| License | Apache 2.0 (since 2011) | — |
| Standard | — | RFC 6716 (2012) |
| Latency | — | 5-60 ms (configurable) |
Typical File Sizes
ALAC
- 3-min song (CD quality) 20-30 MB
- Full album (CD, 10 tracks) 250-400 MB
- Hi-Res 24-bit/96 kHz song 80-120 MB
OPUS
- Voice call (24 kbps) 180 KB/min
- Podcast (48 kbps) 21 MB/hour
- Music (128 kbps) ~1 MB/min
- High-fidelity music (160 kbps) ~1.2 MB/min
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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.
OPUS (Opus 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.
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.
VLC, foobar2000, and the default media players on Windows and macOS handle OPUS 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.
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.