Convert ALAC to AAC — Free Online Converter
Convert Apple Lossless Audio Codec (.alac) to Advanced Audio Coding (.aac) online for free. Fast, secure audio conversion with no watermarks or regist...
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Upload your .m4a file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .aac file when it's ready.
About ALAC to AAC Conversion
ALAC (Apple Lossless Audio Codec) stores bit-perfect audio in M4A containers, achieving roughly 50% compression compared to raw PCM while preserving every sample. AAC (Advanced Audio Coding) is the industry-standard lossy codec, delivering transparent quality at 256 kbps with 10:1 compression ratios. Both ALAC and AAC live in the M4A container — they share the same file format, metadata system, and Apple ecosystem integration.
Converting ALAC to AAC trades lossless quality for dramatically smaller file sizes while remaining within the same M4A container ecosystem. This is the standard workflow for creating distribution copies from lossless masters on Apple platforms.
Why Convert ALAC to AAC?
ALAC files at CD quality occupy roughly 5-6 MB per minute, while AAC at 256 kbps needs only about 2 MB per minute — a 60-70% size reduction with virtually indistinguishable quality. For mobile devices with limited storage, portable music players, and streaming, AAC provides the practical balance of quality and size.
Since both codecs share the M4A container, all metadata — album art, lyrics, chapter markers, iTunes tags, and library organization — transfers perfectly with zero mapping issues. This makes ALAC-to-AAC the smoothest possible lossy conversion within the Apple ecosystem.
Common Use Cases
- Creating compact iPhone copies from ALAC masters while preserving all metadata
- Preparing ALAC music for streaming distribution on Apple Music or iTunes Store
- Reducing Apple Music lossless downloads for devices with limited storage
- Building portable AAC libraries from lossless ALAC collections
- Creating distribution copies from studio ALAC masters for podcast or music release
How It Works
FFmpeg decodes ALAC to PCM (lossless — no quality loss in this step) and encodes using the AAC encoder. Since both formats share the M4A container (MPEG-4 Part 14), the container structure, metadata, and album art are preserved directly. The AAC encoder applies MDCT and psychoacoustic modeling to the perfect PCM input. This single-generation lossy encode from a lossless source produces the best possible AAC quality. The covr (cover art) atom transfers without re-encoding.
Quality & Performance
At 256 kbps AAC-LC, the output is virtually indistinguishable from the ALAC original in blind listening tests — this is considered transparent quality. At 192 kbps, subtle differences may appear on high-end equipment. At 128 kbps, AAC still sounds excellent for casual listening. Since the encode starts from lossless PCM, the AAC output achieves the best possible quality for the chosen bitrate — no generation loss from a previous lossy step.
Device Compatibility
| Device | ALAC | AAC |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Native | Native |
| iPhone/iPad | Native | Native |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No | No |
Recommended Settings by Platform
Spotify
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Apple Music
Resolution: N/A
Bitrate: 256 kbps
AAC format required
SoundCloud
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Podcast
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
Tips for Best Results
- 1Use 256 kbps AAC-LC for music distribution — this is the iTunes Store standard and sounds transparent from ALAC sources
- 2For podcasts and audiobooks, 64-96 kbps AAC is sufficient from ALAC masters and produces very small files
- 3Always keep your ALAC originals — AAC is a one-way lossy process and the lossless masters are your quality insurance
- 4Leverage the shared M4A container for seamless metadata and album art transfer between ALAC and AAC
- 5Batch convert ALAC albums to AAC when creating a portable music library for travel
Related Conversions
ALAC to AAC is the ideal lossy distribution workflow within the Apple ecosystem. Perfect PCM source, shared M4A container, and seamless metadata transfer produce the best possible AAC output.