How to Convert Audio on Mac: GarageBand & QuickTime

macOS ships with four different tools that can convert audio — QuickTime Player, the Music app (formerly iTunes), GarageBand, and the command-line utility 'afconvert' that has been in the OS since the PowerPC era. There is also Homebrew-installed FFmpeg for power users and browser-based converters for anyone who does not want to install anything. Each tool has different format coverage, different quality controls, and different pain points. This guide walks through all five.

Method 1: Browser Converter (No Installation)

The path of least resistance is opening Safari, Chrome, or Firefox and dragging your file into a browser-based converter. AudioUtils runs FFmpeg compiled to WebAssembly inside the page itself, so the file never leaves your Mac — no upload, no account, no install. Conversion speed is roughly 80% of native FFmpeg on Apple Silicon and 60% on Intel Macs.

• AIFF to MP3 — GarageBand and Logic exports
• M4A to MP3 — Voice Memos, Apple Music purchases
• MOV to MP3 — iPhone screen recordings, QuickTime captures
• WAV to FLAC — lossless archiving without size bloat

Use this method when you want a single file converted in under 30 seconds without thinking about codecs, bitrates, or which app on your Mac supports which format.

Method 2: QuickTime Player

QuickTime Player has lived in /Applications since macOS 10.6 and handles audio export through File > Export As. It is the path most Apple support docs recommend for casual conversion.

1. File > Open File (or drag onto QuickTime's dock icon) 2. File > Export As > Audio Only 3. macOS Sonoma and later add a Format dropdown: M4A audio is the only option

Coverage: reads MOV, MP4, M4A, AIFF, WAV, MP3 (newer macOS only), CAF. Writes only M4A (AAC). Bitrate is fixed at roughly 256 kbps with no control. Useful for quickly stripping audio from a MOV screen recording, useless if you need WAV, FLAC, or anything other than AAC.

Method 3: Music App (iTunes Legacy Converter)

The Music app inherited the old iTunes "Convert" feature, and it is the fastest way to do format-controlled batch conversion without leaving Apple's ecosystem:

1. Music > Settings > Files > Import Settings 2. Choose import method: AAC Encoder, AIFF Encoder, Apple Lossless Encoder, MP3 Encoder, or WAVE Encoder 3. Set custom bitrate or sample rate 4. Select tracks in your library, then File > Convert > Create [Format] Version

Coverage: imports MP3, M4A, AAC, AIFF, WAV, ALAC. Outputs MP3 up to 320 kbps, AIFF, WAV, ALAC, AAC. Cannot output FLAC, OGG, or Opus. The MP3 encoder is the LAME-derived one Apple licensed years ago — quality is solid.

Catch: the file must be in your Music library before Convert appears in the menu. For one-off conversions of files outside the library this is more friction than it is worth.

Method 4: GarageBand

GarageBand is the clumsiest of the four built-in routes but the only one that gives you a full waveform editor before exporting:

1. File > New > Empty Project, set tempo to 120 BPM (irrelevant but required) 2. Drag the source audio onto the arrange window 3. Share > Export Song to Disk 4. Pick AIFF, M4A (AAC), MP3 (up to 320 kbps), or Apple Lossless (ALAC) 5. Set Quality (for MP3, "Higher Quality" maps to 256 kbps; "Highest" is 320 kbps)

Coverage: writes AIFF, M4A, MP3, ALAC. No WAV. No FLAC. Good when you want to trim, fade, or normalize before exporting; overkill for pure format conversion.

Method 5: Command Line — afconvert and FFmpeg

afconvert has shipped with macOS since 10.4 and is the no-install option for scripting. It uses Apple's CoreAudio encoders, which produce excellent AAC quality (Apple's AAC encoder is widely considered the best in the industry alongside Fraunhofer FDK).

• WAV to AAC at 192 kbps: 'afconvert -f m4af -d aac -b 192000 input.wav output.m4a'
• AIFF to ALAC: 'afconvert -f m4af -d alac input.aiff output.m4a'
• AIFF to WAV: 'afconvert -f WAVE -d LEI16 input.aiff output.wav'

afconvert cannot write MP3 or FLAC. For those you need FFmpeg.

FFmpeg via Homebrew is the heavyweight option. Install: 'brew install ffmpeg' (about 200 MB with all codecs). Common one-liners:

• AIFF to MP3 (VBR ~190 kbps): 'ffmpeg -i input.aiff -q:a 2 output.mp3'
• M4A to WAV: 'ffmpeg -i input.m4a output.wav'
• MOV to M4A (lossless audio remux, no re-encode): 'ffmpeg -i input.mov -vn -acodec copy output.m4a'
• WAV to FLAC level 8: 'ffmpeg -i input.wav -compression_level 8 output.flac'
• Batch AIFF to MP3: 'for f in *.aiff; do ffmpeg -i "$f" -q:a 2 "${f%.aiff}.mp3"; done'

The '-q:a 2' flag invokes LAME's preset for ~190 kbps VBR (transparent for most listeners). For fixed 320 kbps CBR use '-b:a 320k'.

Choosing the Right Method

| Scenario | Best method | |---|---| | One-off conversion, no install | Browser converter | | Strip audio from a MOV | QuickTime or 'ffmpeg -vn -acodec copy' | | Batch convert a music library | Music app Convert | | Trim or fade before export | GarageBand | | Need MP3 or FLAC output via CLI | FFmpeg | | Best AAC quality, no extra install | afconvert |

macOS-Specific Format Pairs

• AIFF is Apple's uncompressed PCM container. It is identical to WAV in audio content, just with big-endian byte order and a different chunk header. Convert to WAV for Windows tooling, MP3 for sharing, FLAC for archive.
• M4A is AAC inside an MPEG-4 container. Voice Memos, Apple Music purchases (the un-DRM'd ones since 2009), and QuickTime exports all use this. Convert to MP3 for older players or Android compatibility.
• MOV is QuickTime's container. Audio is almost always AAC. Use 'ffmpeg -vn -acodec copy' for a lossless audio extraction; the audio bytes are copied unchanged.
• CAF (Core Audio Format) is Apple's pro-audio container, uncapped at 4 GB unlike WAV. Logic Pro and Final Cut sometimes export this. Convert with afconvert to WAV or AIFF for cross-tool compatibility.

For more on Apple's format ecosystem, see what is AIFF, how to convert MOV to M4A, and the parallel guide for converting audio on iPhone. For the broader question of which lossless format to pick, see FLAC vs ALAC.