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Need help?Extract the Audio from an AVI as M4A
This pulls the soundtrack out of an AVI video and saves it as an M4A file — an MPEG-4 audio container holding AAC, the codec Apple built iTunes and Apple Music around. It is the right tool when you want the narration, music, lecture, or dialogue from a clip without carrying the video around with it. The audio inside an AVI is almost always MP3, AC-3, or uncompressed PCM, so the conversion re-encodes it to AAC rather than copying the stream across; the bitrate table below is there so you pick a setting that does not throw away more than it has to.
How to Convert AVI to M4A
- Upload Your AVI File: Drag and drop the AVI onto the page or click "Add Files" to browse. Several clips can be queued and converted with the same settings.
- Set the Bitrate under File Compression: Open Advanced Options. File Compression opens on Quality Preset, the automatic mode — it is the least predictable control here, and its dropdown preselects "Very High (Recommended)", which is what is sent if you leave it alone — so take direct control with Constant Bitrate or Custom Bitrate (the dropdown runs from 8 kbps to 384 kbps and both open on 128 kbps), with Variable Bitrate and one of its five AAC bands (96k-112k down to 20k-32k), or with Specific file size when you have a byte target to hit.
- Adjust Channels, Sample Rate, or Trim: Audio Channel and Audio Sample Rate both start on ORIGINAL, so the source values carry through unless you switch to MONO, STEREO, or a fixed rate between 8000 Hz and 48000 Hz. Trim starts on "Unchanged"; set a Start time and Duration to keep only part of the recording.
- Convert and Download: Click Convert and save your
.m4a. No sign-up, no watermark.
M4A vs the Other Formats You Could Extract To
| Property | M4A (AAC) | MP3 | WAV (PCM) |
|---|---|---|---|
| Container | MPEG-4 Part 14 | MPEG-1 Audio Layer III | RIFF |
| Compression | Lossy | Lossy | None |
| Quality at the same bitrate | Better than MP3 at low and mid rates | The baseline | Not applicable |
| Typical size for an hour | About 58 MB at 128 kbps | About 58 MB at 128 kbps | Roughly 600 MB at CD rates |
| Plays on Apple devices | Natively, everywhere | Natively | Natively |
| Plays on car stereos and old hardware | Usually | Essentially always | Rarely |
| Right when | You are in the Apple ecosystem or want the best quality per megabyte | Maximum compatibility matters more than efficiency | You are feeding an editor or mastering step |
If the file has to play on absolutely anything, extract to MP3 instead. If you need uncompressed audio for editing, AVI to WAV skips the lossy step entirely. Already have M4A files that something old refuses to open? M4A to MP3 handles that direction.
Choosing a Bitrate
Match the source rather than maximising the number. Encoding at 320 kbps from a 128 kbps MP3 soundtrack produces a bigger file with exactly the same audible detail — the information was already discarded by the first encoder and nothing brings it back.
| Bitrate | Roughly per hour | Suits |
|---|---|---|
| 64 kbps | 29 MB | Speech, lectures, narration, voice memos |
| 96 kbps | 43 MB | Speech where the recording quality is good and you want headroom |
| 128 kbps | 58 MB | The default here — fine for mixed dialogue and background music |
| 192 kbps | 86 MB | Music, matching a typical MP3 soundtrack rate |
| 256 kbps | 115 MB | Music you care about, and the rate Apple's own store settled on |
The Constant Bitrate dropdown runs from 8 kbps up to 384 kbps, and Custom Bitrate lets you type any figure in bps, Kbps, or Mbps. For spoken word you can also halve the file for free by setting Audio Channel to MONO, since a single-microphone recording gains nothing from two identical channels.
Frequently Asked Questions
Will converting AVI to M4A improve the audio quality?
No, and it cannot. The audio inside an AVI has already been encoded once — usually as MP3, AC-3, or PCM — and extracting to M4A decodes that and re-encodes it as AAC. Going from one lossy format to another can preserve quality or lose a little more, never add detail back. To keep the result as close to the source as possible, set a bitrate at or slightly above the original track's. A PCM source is the exception: that is uncompressed, so AAC is a clean first compression with nothing compounding.
Does the M4A keep the video from the AVI?
No. M4A is an audio-only container by convention, so the picture is discarded and what you get back is just the soundtrack. That is usually the entire point — an hour of lecture audio is a fraction of the size of an hour of video. If you actually want to keep the picture and simply change format, use AVI to MP4 instead of an audio extraction.
Is M4A the same thing as AAC?
Not quite — one is the box, the other is what is in it. M4A is a file container defined by MPEG-4 Part 14 (ISO/IEC 14496-14), and AAC is the audio codec stored inside. The container can in principle hold other payloads, including Apple Lossless, which is why you occasionally meet an .m4a that is not AAC at all. This converter writes AAC.
What if my AVI has no audio track, or has several?
If the AVI genuinely has no audio stream there is nothing to extract, and the conversion has no sound to give you — check that the clip plays with audio in a media player first. Multi-track AVIs are unusual outside of specific capture workflows; extraction targets the primary audio stream, so an alternate language or commentary track is not something you can pick between here. For files where that matters, demux in a desktop tool before uploading.
Will the M4A play on Android, Windows, and in a car?
On Android and Windows, almost always — Windows Media Player, the Films & TV app, VLC, and current Android media players all handle AAC in an MP4 container without extra software. Car head units are the weak spot: older units and some aftermarket ones list MP3 and WMA support only, and will skip an .m4a file entirely. If the destination is a car stereo or a decade-old device, MP3 is the safer target.
Can I extract just a section of the audio?
Yes, using Trim. It starts on "Unchanged", and switching it on gives you a Start time and a Duration, each of which accepts either plain seconds or an HH:MM:SS.sss timecode. That is the clean way to drop a silent lead-in, cut a trailing few minutes, or pull one segment out of a long recording. If you need several pieces from one file, or you would rather cut after converting, the audio cutter works on the finished M4A.
How do I hit a specific file size?
Switch File Compression to "Specific file size" and enter your target in bytes, kilobytes, or megabytes — the encoder works backwards to a bitrate that fits. Be realistic about what you are asking for: squeezing an hour of audio into 10 MB means roughly 22 kbps, which will sound rough even for speech. If the number is tight, set Audio Channel to MONO and lower the Audio Sample Rate first, then let the size target handle the rest.
What happens to my AVI file after the conversion?
It is uploaded over an encrypted connection, the audio is extracted and encoded on our servers, and both the upload and the finished M4A are deleted automatically a few hours later. There is no sign-up, no watermark, and files are never shared or made public. Your original file is never modified. Free uploads are limited to 400 MB per file (1 GB on Basic, 4 GB on Pro), so trim a long recording first.