MP4 to M4A Converter

Convert MP4 to M4A Online

Pull the soundtrack out of an MP4 and get back an .m4a — the audio-only form of the same MPEG-4 container, holding an AAC track that phones, Apple Music, VLC, Android and every mainstream player handle without conversion. This is the right output when you want a song, an interview, a lecture or a podcast episode separated from its video and kept small. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours — no sign-up, no watermark.

How to Convert MP4 to M4A

1. Upload Your MP4 File: Drag and drop your .mp4 or .m4v onto the page, or click "Add Files" to browse. Several videos can be queued and converted with the same settings.
2. Choose Variable Bitrate or Constant Bitrate: Open Advanced Options and, under File Compression, switch to Variable Bitrate (five AAC quality ranges) or Constant Bitrate (8 to 384 kbps) and pick a value. These are the two controls that set the AAC encoder's rate explicitly — see the tables below for what to pick.
3. Set Audio Channel, Sample Rate or Trim (Optional): Audio Channel and Audio Sample Rate both start on ORIGINAL, which keeps the video's own values — the usual right answer. Switch Trim from Unchanged to enter a Start time and Duration when you only want one section of a long recording.
4. Convert and Download: Click Convert and save the .m4a. The file is written with its metadata index at the front, so it starts playing before it has finished downloading.

Which Control Actually Sets the Bitrate

File Compression offers several modes, and they do not all do the same job on an AAC target. Two of them give you direct, predictable control:

• Variable Bitrate maps to the AAC encoder's five quality modes. The encoder spends bits where the audio is complex and saves them where it isn't, which is the better choice when you care about consistent quality across a whole recording.
• Constant Bitrate pins every second of audio to the same rate, from 8 kbps up to 384 kbps, with 128 kbps preselected. Use it when a downstream system requires an exact, predictable rate, or when you are matching an existing library.
• Specific file size works backwards from a byte target — useful when something has a hard upload limit.
• Quality Preset is the mode the panel opens on — the automatic, hands-off option. Nothing is pre-selected in its dropdown, so the "Highest" on screen is a placeholder: leave it alone and the server falls back to its own default rather than the label you can see. It is also the least predictable control here, so set Variable Bitrate or Constant Bitrate instead whenever the output rate matters.

Treat those figures as rough guides rather than promises. The encoder's own documentation describes them per channel, but measured against real audio the total rate barely moves with channel count and the top rung overshoots its label — so the honest summary is that higher rungs mean higher quality, without a reliable arithmetic relationship to the numbers printed on them. If you need a predictable rate, use Constant Bitrate instead.

How Big the M4A Will Be

Constant Bitrate makes the output size pure arithmetic: rate ÷ 8 gives kilobytes per second.

A useful sanity check before you convert: the audio track inside your MP4 already has a bitrate, and encoding above it cannot recover anything. If the source is a 128 kbps AAC track, asking for 320 kbps just makes a bigger file containing the same audio plus a second generation of encoding artefacts.

Frequently Asked Questions

Is converting MP4 to M4A lossless?

No, and it cannot be here. The audio is decoded and re-encoded as AAC, so this is a second lossy generation on top of whatever the MP4 already went through. At the higher Variable Bitrate settings the difference is inaudible to almost everyone, but it is not a byte copy. This page offers AAC only — there is no ALAC or lossless option on it — so if you need genuine losslessness, extract to FLAC instead, or to WAV if a tool insists on uncompressed PCM.

Are the Variable Bitrate numbers per channel or the total?

Neither reliably. The encoder's documentation states them per channel, which would mean a stereo file runs at double the printed figure — but that is not what the encoder actually does. Encoding the same source as mono and as stereo at the top rung produced almost the same overall bitrate, and the result sat well above the "96k-112k" the label promises. Read the five rungs as an ordered quality scale, not as arithmetic: higher is better, and the top rung is the highest quality the page offers. When you need a number you can predict and plan around, switch to Constant Bitrate.

Which setting should I use if I just want it to sound good?

Pick Variable Bitrate at 96k-112k for music, or 32k-40k for speech. VBR lets the encoder allocate bits where they matter, so quality stays even across quiet and dense passages. If you would rather have a predictable file size, use Constant Bitrate at 192-256 kbps for music and 96-128 kbps for spoken word. Naming one of these explicitly is what gives you a result you can predict; leaving File Compression on Quality Preset hands the decision to the server's own default, since nothing is pre-selected in that dropdown.

Is M4A the same as MP4 audio?

Effectively, yes. Both use the MPEG-4 Part 14 container (ISO/IEC 14496-14), which descends from Apple's QuickTime format. An .m4a file is simply an MPEG-4 file that carries an audio track and no video. The separate extension exists so operating systems and media players file it under music rather than video — double-clicking it opens a music player instead of a video player, which is the whole practical point.

Will M4A play on Android and Windows, or only on Apple devices?

It plays broadly. M4A began as an Apple convention but AAC-in-MP4 is supported by Android, Windows, browsers, VLC, most car head units made in the last decade and virtually every modern phone. The narrow exceptions are older or deliberately minimal devices that only read MP3 — some car stereos, gym equipment and basic MP3 players. For those, convert to MP3 instead.

Should I choose M4A or MP3?

For anything new, M4A with AAC is the better default: AAC was designed as MP3's successor and generally sounds better at the same bitrate, which means smaller files for equivalent quality. Choose MP3 only when a specific device or workflow requires it — MP3's advantage is universal compatibility, not fidelity. If you need the file in both formats, convert once to M4A and then run M4A to MP3 on the result.

Can I extract just part of the video's audio?

Yes. Switch Trim from Unchanged and enter a Start time and a Duration, either in seconds or as HH:MM:SS.sss. Only that segment is encoded, which shortens both the conversion and the output. This is the practical way to lift one song out of a concert recording or one answer out of a long interview without editing anything afterwards.

My M4A is too large — what are my options?

In order of impact: lower the Constant Bitrate (dropping from 256 to 128 kbps roughly halves the file), set Audio Channel to MONO when the source is speech, or Trim to the section you actually need. If you have a hard byte limit to hit, use the "Specific file size" mode and type the target directly. For a file you have already downloaded, Compress M4A does the same job without re-extracting from the video.

What happens to my video after conversion?

It is uploaded over an encrypted connection, converted on our servers, and deleted automatically after a few hours. There is no sign-up, no watermark, and your files are never shared or made public. Only the audio track is read during the conversion — the video is discarded rather than stored alongside the result.