AVI to AAC Converter

Extract AAC Audio from AVI

This page throws away the video track of an AVI and re-encodes the soundtrack as AAC — Advanced Audio Coding, the codec standardised in the MPEG-4 Audio specification (ISO/IEC 14496-3) and used by YouTube, Apple devices, digital radio and practically every modern streaming service. Worth knowing before you click: a .aac file is a raw ADTS stream, not a tagged music file. If you want something that shows a title and artwork in a music library, AVI to M4A wraps the same AAC audio in an MP4 container instead. If you want maximum compatibility with old hardware, AVI to MP3 is the safer target.

.aac vs .m4a vs .mp3 — Side by Side

When to Extract to .aac

• You are feeding a streaming or broadcast pipeline that expects a packed AAC elementary stream, as HLS does for audio-only renditions.
• A piece of software or hardware explicitly names .aac in its accepted input list.
• You want the audio at the smallest sensible size and you do not care about tags, artwork or chapter data.
• You will remux the audio into another container yourself later on.

When to Pick MP3 or M4A Instead

• You want it in a music app with a title and cover art. Use AVI to M4A — same codec, but the MP4 container carries the metadata a library needs.
• It has to play on a car stereo, an old MP3 player or a cheap Bluetooth speaker. AVI to MP3 is the format those devices were built around.
• You need a lossless master for editing. Neither AAC nor MP3 will do; AVI to WAV writes uncompressed PCM.

How to Convert AVI to AAC

1. Upload Your AVI File: Drag your .avi onto the page or click "Add Files". Queue several clips and they all convert with the same settings; the video track is discarded from each.
2. Choose How Quality Is Set: File Compression opens on Quality Preset, the automatic mode — see the FAQ below for why it is the wrong place to set a rate you care about. Switch to Constant Bitrate for an exact value (the dropdown runs from 8–384 kbps and opens on 128 kbps), Custom Bitrate to type one, Variable Bitrate to pick one of the five AAC bands (96k-112k down to 20k-32k), or Specific file size to aim at a target in megabytes.
3. Set Audio Channel, Sample Rate and Trim (Optional): Audio Channel stays on ORIGINAL unless you fold down to STEREO or MONO; Audio Sample Rate offers ORIGINAL plus fixed rates from 8000 Hz to 48000 Hz; Trim takes a start time and a duration in seconds or as HH:MM:SS.sss.
4. Convert and Download: Click Convert and save the .aac. No sign-up, no watermark. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours.

Choosing a Bitrate

The Constant Bitrate dropdown runs from 8 kbps to 384 kbps. These are sensible starting points rather than rules:

Bear in mind that the audio inside an AVI is usually already MP3-compressed, so this is a lossy-to-lossy re-encode. Choosing a bitrate at or above the source's own rate keeps the second generation of loss inaudible; going far above it wastes space without recovering anything.

Frequently Asked Questions

Is the output a normal audio file I can add to my music library?

Not really — and this trips people up. In our testing the .aac this page produces is a raw ADTS stream: media tools report the format as "raw ADTS AAC" rather than as an MP4 container. It plays fine in VLC, foobar2000 and most desktop players, but it has nowhere to store a title, artist, album art or chapters, so music libraries handle it awkwardly. For a library file use AVI to M4A, which holds identical AAC audio in a container that supports tags.

How much smaller will the file be than the AVI?

Dramatically, because the entire video stream is discarded. The result depends only on bitrate and duration: an hour of audio at 128 kbps is about 57 MB, and at 192 kbps about 86 MB, regardless of how large the source video was. A one-hour AVI lecture that started at several hundred megabytes therefore lands comfortably inside a typical email attachment limit at speech bitrates.

Does converting AVI to AAC lose quality?

Some, yes — AAC is a lossy codec and the AVI's soundtrack was almost certainly lossy already, so this is a second encode. In practice the loss is hard to hear if you encode at or above the source bitrate. AAC also degrades more gracefully than MP3 as the bitrate drops, which is why 96 kbps AAC generally sounds better than 96 kbps MP3.

Why is there no "target file size as a percentage" control on this page?

Because there is no meaningful source audio size to take a percentage of once the video has been removed — the ratio would be against the whole AVI, which tells you nothing useful. Instead, use Specific file size and enter the size you actually need in megabytes, or set a bitrate directly and let duration decide the result.

Can I extract only part of the AVI?

Yes, using the Trim controls. Set a start time and a duration, either as plain seconds or in HH:MM:SS.sss form for frame-level precision. This is the cleanest way to pull a single song, quote or segment out of a long recording, and it also cuts the encode time.

Should I change the sample rate or channel count?

Usually not — leaving both on ORIGINAL preserves what the source had. Two exceptions are worth knowing. Folding a stereo lecture down to MONO roughly halves the data needed for the same perceived clarity of speech. And dropping the sample rate to 24000 Hz or below discards the top octave of treble, which is acceptable for voice and destructive for music.

Which control on this page actually sets the bitrate?

Constant Bitrate, or Custom Bitrate when you want a figure that is not in the list — those are the settings that map one-to-one onto the encoder, so they are the ones to use when you need a predictable, reproducible number for a specification or a broadcast delivery sheet. Variable Bitrate and its five bands are the alternative when you would rather target quality and let the size vary. The Quality Preset dropdown is the automatic, hands-off mode: it displays "Highest" when the page loads, but nothing is actually selected there, so leaving it alone hands the decision to the server's own fallback rather than the rung on screen. It is also the least predictable control here, so when the output rate matters, name it explicitly and confirm it in your player's file-info panel.

How are my files handled after conversion?

Your AVI is uploaded over an encrypted connection, the audio is extracted and encoded on our servers, and both the upload and the finished .aac are deleted automatically after a few hours. There is no sign-up, no watermark, and files are never shared or made public.