M4A to MP3の使い方
- 1
Add the M4A files
Drop up to 3 .m4a files — iPhone Voice Memos, iTunes or Apple Music downloads you own, WhatsApp audio — of up to 500 MB and 10 minutes each.
- 2
Keep MP3 at 192 kbps or adjust
Voice memos sound fine at 96 or 128 kbps; for music choose 192, 256 or 320 kbps, or VBR.
- 3
Optionally even out the volume
Normalize loudness lifts quiet voice memos and meeting recordings to a steady −16 LUFS.
- 4
Convert and download
Each file becomes name.mp3, ready to copy to a car stereo, an old MP3 player or a Windows PC.
制限と Pro
Up to 3 M4A files per batch, each up to 500 MB and 10 minutes long.
Pro converts batches of up to 500 files, each up to 4 GB and 10 hours long. Pro を見る
M4A to MP3 について
M4A is the audio-only flavour of MP4. Apple uses it for Voice Memos, GarageBand exports, iTunes Store purchases and ringtone sources, and many Android recorders and messaging apps save in it too. Inside is usually AAC, a lossy codec that sounds better than MP3 at the same size, or sometimes ALAC, Apple's lossless codec. Plenty of hardware still can't read it: car stereos, older MP3 players, some smart speakers, school and office upload forms, and audio editors on Windows often want MP3.
The conversion decodes the AAC or ALAC audio and encodes it with LAME into MP3, constant bitrate from 64 to 320 kbps or variable bitrate V0 to V6. Going from one lossy codec to another costs a small amount of quality, so use a bitrate at least as high as the original: a typical iPhone voice memo is 64 kbps mono AAC, while iTunes music is 256 kbps AAC, for which 256 or 320 kbps MP3 is the sensible match. ALAC files are lossless, so any MP3 bitrate is the only loss they suffer.
Title and artist tags are copied into the MP3 and can be edited first. Files bought from iTunes before 2009 with FairPlay DRM (.m4p) can't be converted. If the device you are converting for accepts M4A, it's better to keep the original file.
プライバシー
The M4A files are decoded and turned into MP3 inside this browser tab, using WebCodecs with a WebAssembly LAME encoder, or ffmpeg.wasm in a Web Worker when the browser can't decode them. Your recordings are never uploaded or stored, which matters for private voice memos.