AVI to M4A Converter
FileFlip converts AVI to M4A entirely inside your browser, using WebCodecs and FFmpeg compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert an AVI file to M4A?#
- Drop your AVI file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to M4A and the conversion starts on its own. FileFlip usually downloads nothing, falling back to 30.8 MB of WebAssembly if your browser cannot encode these codecs itself, then runs WebCodecs and FFmpeg on your own machine.
- Save the M4A file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting AVI to M4A lose quality?#
Sometimes. When the codecs inside the AVI file are ones the M4A container can hold, the streams are copied straight across and nothing at all is lost. When they are not, the file has to be decoded and encoded again, and that step does cost a little quality.
Is it safe to convert AVI files online?#
Yes, because nothing is uploaded. FileFlip converts AVI files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What AVI to M4A actually does to the file#
Converting AVI to M4A runs on WebCodecs and FFmpeg, usually downloads nothing, falling back to 30.8 MB of WebAssembly if your browser cannot encode these codecs itself, copies the streams through when the codecs fit and re-encodes when they do not, and drops video tracks.
| Engine | WebCodecs and FFmpeg |
|---|---|
| Conversion path | One step: AVI → M4A |
| Downloaded to your browser | Nothing in most browsers, or 30.8 MB if yours cannot encode these codecs itself |
| Quality | Lossless when the codecs fit, lossy when they do not |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Encoded streams | Sometimes | Survives for some files and not others. |
| Video tracks | Dropped | The target format has nowhere to put it. |
Worth knowing before you start:
- whether the browser can do this without FFmpeg depends on the codecs it exposes through WebCodecs
- the encoded streams are copied when the file's codecs fit the target container, and re-encoded when they do not
What is an AVI file?#
An AVI file interleaves video and audio in chunks of Microsoft's RIFF structure, the container Windows has used for video since 1992 and the one most video from the DivX and Xvid years is stored in.
Keep a file as AVI when it is going into software old enough to predate MP4, which is the one situation where the format's age helps.
Convert AVI to MP4 to get the video playing on phones, browsers and TVs, and to shrink it, since what is inside an AVI is usually a codec generation or two behind.
What is an M4A file?#
An M4A file is an MPEG-4 audio container, almost always holding AAC-compressed audio and occasionally Apple Lossless (ALAC), that Apple labels with the .m4a extension to mark an MPEG-4 file as audio-only rather than video.
Use M4A for anything staying inside Apple's ecosystem, especially iTunes and Music libraries and Apple Lossless archives.
Convert M4A to MP3 for compatibility with players and devices that don't support AAC, or to FLAC if the M4A holds ALAC and you want a more widely supported lossless format.
AVI to M4A questions people ask#
Why won't my AVI file play?
An AVI that will not play is usually encoded with a codec the machine does not have. AVI identifies its video by a four character code and leaves the decoder to the operating system, which is why Windows users spent years installing codec packs. Old DivX, Xvid, Indeo and Cinepak files all hit this. VLC ships its own decoders and plays most of them, and converting to MP4 removes the problem permanently.
Is AVI a codec or a container?
AVI is a container, and an unusually open-ended one. Any codec that registers a four character code can go inside, so AVI files from different eras hold wildly different things: MJPEG from a camera, Cinepak from a CD-ROM, DivX or Xvid from a download. That is why one AVI plays instantly and the next one shows a black screen on the same computer.
Does converting AVI to MP4 lose quality?
Converting AVI to MP4 nearly always re-encodes the video, so some quality is lost. AVI predates H.264 and H.265, which is what MP4 players expect, so the old DivX or Xvid stream cannot simply be rewrapped the way an MKV can. Encoding at a generous bitrate keeps the loss invisible in practice, and the result usually still ends up smaller than the AVI.
Why is my AVI file so large?
AVI files are big because of what is inside them rather than the container itself. The codecs of the era, MJPEG and DivX among them, need several times the bitrate H.265 does for the same picture, and MJPEG stores every frame as a separate JPEG with no saving between frames at all. Re-encoding the same footage to H.264 or H.265 in an MP4 commonly cuts the file to a fraction of its size.