Convert MID to ALAC — Free Online Converter
Convert Standard MIDI (.mid) to Apple Lossless Audio Codec (.alac) online for free. Fast, secure audio conversion with no watermarks or registration....
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Upload your .mid 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 .m4a file when it's ready.
About MID to ALAC Conversion
MID (Standard MIDI File) encodes musical performance as a sequence of instructions — note events, velocity, timing, channel assignments, pitch bends, and control changes. MIDI files are extraordinarily compact (10-100 KB) because they contain no audio, only a recipe for producing music. The actual sound depends entirely on the synthesizer interpreting these instructions.
ALAC (Apple Lossless Audio Codec) compresses audio without losing any data — every PCM sample is perfectly preserved. Converting MID to ALAC renders the MIDI performance through a software synthesizer and saves the result as losslessly compressed audio. This gives you a space-efficient Apple-ecosystem-compatible file that preserves the full quality of the synthesis.
Why Convert MID to ALAC?
MIDI's dependency on external synthesizers means playback is unpredictable across devices. ALAC captures a specific rendered version with bit-perfect audio preservation while using roughly 50-60% of the space that uncompressed AIFF or WAV would require. For Apple users, ALAC integrates seamlessly with iTunes, Apple Music, iPhone, iPad, and Mac.
ALAC is the ideal format when you need lossless archival of a MIDI rendering within Apple's ecosystem. Unlike AAC, no audio data is discarded during encoding. Unlike AIFF, the file is significantly smaller. This makes ALAC the best balance of quality and efficiency for MIDI renders destined for Apple devices.
Common Use Cases
- Archiving MIDI composition renders in Apple's lossless format for iTunes library management
- Sharing losslessly rendered MIDI arrangements with collaborators using Apple devices
- Building a sample library from MIDI-rendered instrument sounds with zero compression loss
- Storing MIDI soundtrack renders for video projects in a space-efficient lossless format
- Creating reference renders of MIDI scores for comparison against live recordings
How It Works
FFmpeg decodes the MIDI file's event stream using its built-in MIDI decoder and routes events to a software synthesizer loaded with a SoundFont bank. The synthesizer generates PCM audio by mapping MIDI program numbers to instrument patches, applying note-on/off with velocity-scaled amplitude, processing pitch bend and modulation, and mixing all 16 MIDI channels to a stereo output. This PCM stream is then compressed using the ALAC encoder (lossless — every sample is recoverable) and packaged in an M4A (MPEG-4) container with proper metadata atoms.
Quality & Performance
ALAC encoding is mathematically lossless — the decoded output is bit-identical to the PCM input. Therefore, the only quality variable is the synthesizer and SoundFont. A SoundFont with 24-bit samples, multiple velocity layers, and release samples produces natural-sounding results. The default GM bank sounds functional but synthetic. ALAC simply preserves whatever the synthesizer outputs, with 50-60% size reduction compared to raw PCM.
Device Compatibility
| Device | MID | ALAC |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Native |
| iPhone/iPad | Partial | 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
- 1Keep the original MIDI file archived alongside the ALAC render — MIDI can be re-rendered with improved SoundFonts in the future
- 2Use a SoundFont with at least 200 MB of samples for noticeably better instrument realism over the default GM bank
- 3Render at 44.1 kHz for music consumption or 48 kHz if the ALAC will be used in video production
- 4Tag the ALAC output with proper metadata (title, artist, album) since MIDI metadata rarely transfers automatically
- 5Compare ALAC and AAC renders side-by-side — if you cannot hear a difference, AAC saves significant storage space
MID to ALAC renders MIDI instructions into losslessly compressed audio optimized for Apple's ecosystem. The SoundFont determines musical quality; ALAC preserves it bit-perfectly.