What is this MP4 to M4A converter?
A free, browser-based tool that extracts the audio track from a MP4 video and saves it as M4A. Add a file, preview it inline, and download the result. All processing happens locally in your browser, so your file is never uploaded and there is no watermark.
MP4 to M4A: the extraction with no generation loss
MP4 and M4A belong to the same MPEG-4 container family; an M4A is essentially an MP4 that holds only audio. Since the audio inside an MP4 is almost always AAC, going to M4A means lifting that AAC track out and rewrapping it: no decoding, no re-encoding, no new compression artifacts. The M4A carries the video's audio bit for bit.
That makes this the default route for archiving talk audio, saving a voiceover out of a finished edit, or pulling a music bed back from a render, any case where the goal is keeping exactly what the video had.
When M4A is the right target, and when MP3 still is
Prefer M4A when the audio will be edited again, when it stays in the Apple ecosystem (iPhone, iPad, and Mac play it natively), or when quality retention is the point: re-encoding to MP3 would add a lossy generation for no benefit. Reach is the one argument for MP3, since very old car head units and legacy players may not read M4A.
Size barely changes the call. AAC in consumer video usually sits between 96 and 256kbps, about 1 to 2MB per minute, so a 3-minute 4K clip near 1GB carries roughly 3MB of audio. Keep inputs to around 200MB, which 4K footage reaches within a few minutes; trim longer material first.
How to use it
- Add a MP4 file on the left (drag & drop or click) — it shows an inline preview.
- Pick a quality preset (used only for lossy targets like MP3/M4A/OGG).
- Press “Convert & download” to get your M4A file. The first run downloads the ~30MB converter once.
Lossy vs lossless audio
WAV and FLAC are lossless — they preserve the original waveform exactly (FLAC is compressed, WAV is not). MP3, M4A (AAC) and OGG are lossy: they shrink the file by discarding inaudible detail, and the quality preset controls the bitrate. Converting a lossy file to a lossless format can't recover quality that was already lost. One special case: converting to M4A when the source is already AAC just repackages the container (a lossless remux) — instant and bit-exact.
