Convert AVI to M4A — Free Online Tool
Extract and convert the audio track from an AVI file into M4A format, encoding it as AAC at 128kbps while discarding the video stream entirely. Ideal for pulling clean audio from legacy AVI recordings into a modern, iTunes-compatible container.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your AVI file here
or click to browse
Free — no uploads, no signups. Your files never leave your browser.
Settings
Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
AVI files store interleaved audio and video streams — the audio is most commonly encoded as MP3 (libmp3lame) or PCM, while the video might use H.264, MJPEG, or other codecs. This conversion strips the video stream completely and re-encodes only the audio into AAC (Advanced Audio Coding), wrapping it in an MPEG-4 container with the .m4a extension. Because AVI's native audio codec is almost never AAC, a full re-encode of the audio is necessary rather than a simple stream copy. The result is a compact, audio-only file optimized for music players, podcasts, and Apple ecosystem apps — without any of the overhead from the original video data.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool. In the browser version of this tool, FFmpeg runs locally via WebAssembly (FFmpeg.wasm), so your AVI file never leaves your device. |
-i input.avi
|
Specifies the input AVI file. FFmpeg reads the interleaved audio and video streams from this legacy Microsoft container to determine what codecs and streams are present. |
-c:a aac
|
Sets the audio codec to AAC (Advanced Audio Coding) for the output. Because AVI's audio is typically MP3 or PCM — neither of which can be placed natively in an M4A container — a full re-encode to AAC is required. |
-b:a 128k
|
Encodes the AAC audio stream at 128 kilobits per second, which is the default balance of file size and quality suitable for voice, podcasts, and casual music listening. Raise this to 192k or 256k for higher-fidelity music from AVI source files. |
-vn
|
Disables video output entirely, which is essential here because M4A is an audio-only container. This flag tells FFmpeg to ignore the video stream from the AVI source and produce a pure audio file. |
output.m4a
|
The output filename with the .m4a extension, which signals FFmpeg to write an MPEG-4 audio container. This format is natively recognized by Apple iTunes, iOS, macOS, Android, and most modern media players. |
Common Use Cases
- Extract a voice recording or interview from an old AVI camcorder file to share as a podcast episode or audio archive
- Pull the audio track from an AVI music performance or concert recording to play in iTunes, Apple Music, or on an iPod
- Convert legacy AVI lecture recordings from early 2000s educational software into M4A files compatible with modern course platforms and mobile devices
- Strip the audio from an AVI screen recording or tutorial video to create a standalone audio commentary track
- Reduce the storage footprint of large AVI video archives where only the spoken-word or musical audio content needs to be preserved
- Prepare audio extracted from AVI files for use in iOS apps or Apple CarPlay, which natively support M4A/AAC but often struggle with AVI containers
Frequently Asked Questions
Yes, there will be some quality loss because this conversion re-encodes the audio — it reads whatever codec was in the AVI (typically MP3 or PCM) and encodes it fresh as AAC. This is a generation loss scenario: even if you use a high bitrate, you are not doing a lossless copy. If the original AVI had uncompressed PCM audio, the quality loss is minimal at 128kbps AAC. If the original was already compressed as MP3, re-encoding introduces a small additional quality reduction.
The dramatic size reduction comes from two factors: the video stream is discarded entirely (which typically accounts for 90–95% of an AVI file's size), and the audio is encoded as AAC, which is more efficient than MP3 or PCM at equivalent perceptual quality. A 1GB AVI video file might produce an M4A file of only 5–30MB depending on the duration and chosen audio bitrate.
The M4A format does technically support chapters, but AVI does not — AVI has no native chapter structure. Since there are no chapter markers in the source file to carry over, your output M4A will not contain any chapters. If you need chapter markers in the M4A, you would need to add them manually using a tool like mp4chaps or a tag editor after the conversion.
By default, FFmpeg selects the first (primary) audio stream from the AVI file for conversion. M4A does not support multiple audio tracks in the same way AVI does, so only one track will be included in the output. If you need a specific secondary audio track, you can modify the FFmpeg command by adding '-map 0:a:1' (for the second audio track) before the output filename.
Replace the '-b:a 128k' value in the command with a higher bitrate such as '-b:a 192k', '-b:a 256k', or '-b:a 320k'. For most spoken-word content, 128kbps AAC is transparent, but for music with complex instrumentation, 192k or 256k AAC will better preserve detail. The full command at 256kbps would be: ffmpeg -i input.avi -c:a aac -b:a 256k -vn output.m4a
Yes. On Linux or macOS, you can run a shell loop: 'for f in *.avi; do ffmpeg -i "$f" -c:a aac -b:a 128k -vn "${f%.avi}.m4a"; done'. On Windows Command Prompt, use: 'for %f in (*.avi) do ffmpeg -i "%f" -c:a aac -b:a 128k -vn "%~nf.m4a"'. This applies the identical conversion settings to every AVI file in the current directory.
Technical Notes
AVI is a legacy container from 1992 that uses a simple index-based interleaving structure, and its audio streams are commonly PCM, MP3, or AC-3 — none of which can be stream-copied directly into an M4A container. M4A is an ISO Base Media File Format (ISOBMFF) container, the same family as MP4, but restricted to audio-only content by convention. The -vn flag is mandatory here because M4A has no video codec track; without it, FFmpeg would error out or fallback awkwardly. The chosen AAC encoder is FFmpeg's native 'aac' codec, which is broadly compatible with Apple devices, Android, web browsers, and streaming platforms. One limitation to be aware of: AVI files occasionally store audio with a variable frame rate or misreported sample rate in their headers — if your output M4A sounds sped up or slowed down, adding '-ar 44100' or '-ar 48000' to force a standard sample rate before the output filename usually resolves the issue. ID3-style metadata tags embedded in the AVI (artist, title) are not automatically mapped to iTunes-style atoms in M4A; you may need to re-tag the output file using a tool like MusicBrainz Picard or mp4tags.