Convert ALAC to FLAC — Free Online Tool
Convert ALAC audio files (.m4a) to FLAC, moving from Apple's proprietary lossless codec to the open-source FLAC standard — with zero quality loss since both formats are fully lossless. This is ideal for breaking free from Apple ecosystem lock-in while preserving every bit of your original audio fidelity.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
ALAC and FLAC are both lossless codecs, meaning they store the full uncompressed PCM audio data using different compression algorithms. During this conversion, FFmpeg decodes the ALAC-encoded audio from the MPEG-4 container (.m4a) back to raw PCM, then re-encodes it using the FLAC codec and writes it into a standalone .flac file. Because both codecs are lossless, the decoded PCM data is mathematically identical at both ends — the output FLAC file is an exact audio copy of your ALAC source, just repackaged with open-standard compression. Metadata tags (artist, album, track number, etc.) are carried over, though ALAC-specific iTunes fields and chapter markers are not supported by the FLAC container and will be dropped.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool, the underlying engine that handles all decoding, encoding, and container remuxing for this conversion. |
-i input.m4a
|
Specifies the input file — an .m4a file containing an ALAC-encoded audio stream inside an MPEG-4 container, which is the standard file format produced by Apple Music, iTunes rips, and Apple device recordings. |
-c:a flac
|
Instructs FFmpeg to encode the audio stream using the FLAC codec, replacing the ALAC compression with FLAC's open-source lossless compression algorithm while keeping the same underlying PCM audio data. |
-compression_level 5
|
Sets FLAC's compression effort to level 5 (the default, on a scale of 0–8), balancing encode speed against output file size — higher values produce smaller files at the cost of slower encoding, with no effect on audio quality at any level. |
output.flac
|
Defines the output filename with the .flac extension, which tells FFmpeg to write the encoded audio into a standalone FLAC container — the standard open format understood by virtually all non-Apple audio players and libraries. |
Common Use Cases
- Moving your Apple Music or iTunes lossless library to a Linux-based media server like Jellyfin or Navidrome, which have broader native support for FLAC than ALAC
- Preparing audio files for upload to music distribution platforms or archiving services that require or strongly prefer open FLAC over proprietary ALAC
- Making your lossless music collection compatible with non-Apple portable players (e.g., Astell&Kern, FiiO, or most Android-based DAPs) that support FLAC but not ALAC
- Contributing recordings or releases to open-source music archives and Creative Commons platforms that mandate open formats
- Converting a ripped Apple Lossless CD backup to FLAC for long-term archival, since FLAC's open specification is more future-proof against format obsolescence
- Sharing lossless audio files with collaborators or mastering engineers whose DAWs and tools handle FLAC more universally than the M4A/ALAC container
Frequently Asked Questions
No — this is a lossless-to-lossless conversion with no quality degradation whatsoever. FFmpeg decodes the ALAC stream to raw PCM and re-encodes it with FLAC, and because both codecs are lossless, the decoded PCM is bit-for-bit identical at every stage. The resulting FLAC file will reproduce exactly the same audio waveform as your original ALAC file. If you compare audio fingerprints or spectrograms of the two files, they will be indistinguishable.
Standard tags like artist, album, title, track number, and genre are generally preserved, as both ALAC (stored in iTunes-style MP4 atoms) and FLAC (stored as Vorbis comment blocks) support these common fields. However, some iTunes-specific metadata fields and any chapter markers embedded in the ALAC file will be lost, since the FLAC container does not support chapters. Embedded album artwork may transfer depending on how it was stored in the source file, but it is worth verifying after conversion.
ALAC and FLAC use different lossless compression algorithms, so their file sizes will differ even though they encode the same underlying audio. FLAC at its default compression level 5 often achieves slightly better compression ratios than ALAC for many types of music, which may result in a smaller output file. However, the size difference is purely a function of compression efficiency — it does not reflect any difference in audio quality.
You can change the FLAC compression level by modifying the '-compression_level' value in the command, using any integer from 0 to 8 (e.g., '-compression_level 8' for maximum compression). This setting only affects encode time and file size — a higher level compresses more aggressively and produces a smaller file, but takes longer to process. Since FLAC is lossless at every compression level, audio quality is identical regardless of the value you choose. The default of 5 is a well-balanced choice for most use cases.
Yes. On Linux or macOS, you can run a shell loop such as: for f in *.m4a; do ffmpeg -i "$f" -c:a flac -compression_level 5 "${f%.m4a}.flac"; done — this processes every .m4a file in the current directory and outputs a matching .flac file. On Windows, a similar batch script or PowerShell loop achieves the same result. This approach is especially practical for large libraries over 1GB, where the browser-based tool's per-file processing would be slower than a single bulk desktop command.
FLAC is widely regarded as the more future-proof archival format because it is fully open-source with a published specification that is not controlled by any single company, making it immune to licensing changes or corporate decisions. ALAC, while Apple open-sourced its reference implementation in 2011, remains associated with Apple's ecosystem and the MPEG-4 container. FLAC also has broader support across media players, operating systems, and archival standards. For a personal collection you intend to preserve long-term without Apple platform dependency, FLAC is the stronger choice.
Technical Notes
ALAC is stored inside an MPEG-4 container (.m4a), which is the same container used for AAC audio and MP4 video — the codec embedded within is what makes it lossless. FLAC, by contrast, is typically stored in its own dedicated container (.flac), which is simpler and more universally readable by audio software. During conversion, FFmpeg strips the M4A container entirely, decodes the ALAC codec to PCM, then re-encodes to FLAC. One known limitation is that ALAC supports only a single audio track per file and has no subtitle support, which matches FLAC's own constraints — so no stream selection conflicts arise. FLAC natively supports ReplayGain tags, cue sheets, and seeking metadata that ALAC does not expose as directly, giving the output file potential advantages in compatible players. Sample rates up to 384kHz and bit depths up to 32-bit are supported by both codecs, so high-resolution audio from Apple's lossless streams (24-bit/192kHz) converts cleanly without any downsampling. The one irreversible data loss in this conversion is ALAC chapter markers, which are an MPEG-4 container feature with no FLAC equivalent.