AVI to FLAC Converter

How to Convert AVI to FLAC (Step-by-Step)

1. Upload Your AVI File: Drag and drop the video or click "+ Add Files" to select it.
2. Set the Compression Level: Open Advanced Options and choose a level from 1 to 12.
3. Adjust Audio Channel and Sample Rate: Leave both on "Original" unless you need otherwise.
4. Convert and Download: Click "Convert" and save your FLAC. No sign-up, no watermark.

This guide is for anyone who wants to pull the audio track out of an AVI video and save it as a lossless FLAC file. By the end you will have a standalone FLAC that holds the exact audio stream from your AVI — with one important caveat about quality that we cover below. The walk-through expands on each step.

Step 1 — Upload Your AVI File

Drag and drop your AVI onto the page, or click "+ Add Files" to pick it from your computer. You can queue several AVI files and convert them in one batch; each one produces its own FLAC. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up and no watermark. The main thing that limits a large AVI here is upload size and time, not your device, so a multi-gigabyte movie just takes longer to send.

Step 2 — Set the Compression Level

Open Advanced Options to reach the Compression level slider, which runs from 1 to 12. This number controls how hard FLAC works to shrink the file, not the audio quality — every level is lossless and decodes back to identical samples. A lower number encodes faster but leaves a slightly larger file; a higher number squeezes a few percent more off at the cost of encode time.

• Want the smallest archive file and don't mind waiting: push the slider toward 12.
• Want the fastest conversion and don't care about a few extra megabytes: leave it low (around 5).
• Not sure: the default is a sensible middle ground and the size difference between levels is usually small.

Step 3 — Adjust Audio Channel and Sample Rate (Optional)

Below the slider, the Audio Channel and Audio Sample Rate dropdowns both default to "Original," which copies the AVI's audio as-is — the right choice in almost every case. Set Audio Channel to Mono only if you specifically need a single-channel file (for example, voice that started in mono anyway). Leave Audio Sample Rate on Original unless a target device needs a specific rate; resampling a track to a higher rate adds no real detail, so there is no quality reason to raise it. Use Trim if you only want a clip rather than the whole track.

Step 4 — Convert and Download

Click "Convert" and download your FLAC when it finishes. There is no sign-up and no watermark, and the output plays in VLC, foobar2000, and natively in Chrome 56+, Firefox 51+, Edge 16+, and Safari 13+.

Common Errors and How to Fix Them

• "My FLAC doesn't sound any better than the AVI" — This is the most common surprise. FLAC is lossless, but it can only preserve the audio that was already inside the AVI. Most AVI files store lossy audio (MP3 or AC-3), so wrapping that stream in FLAC keeps it bit-for-bit but cannot rebuild detail the original lossy encode threw away. FLAC restores nothing; it just stops any further loss from here on.
• "The FLAC file is much bigger than the AVI's audio" — Expected. A 192 kbps MP3 track expands a lot when re-encoded losslessly, because FLAC has to represent every decoded sample rather than the compact lossy approximation. If small size matters more than lossless, convert to AVI to MP3 instead.
• "The output is silent" — The AVI probably has no audio stream, or its audio codec failed to decode. Confirm the file actually plays sound in VLC first; a video-only AVI cannot produce audio.
• "My player won't open the FLAC" — Older or stock media players sometimes lack a FLAC decoder. Use VLC or foobar2000, or update the browser/app to a version listed in Step 4.
• "Raising the sample rate didn't improve quality" — Upsampling cannot add information that was never recorded. Keep Sample Rate on Original.

When This Doesn't Work

If the AVI is corrupted, only partially downloaded, or its audio uses a codec that won't decode, the conversion may fail or come out silent — repair or re-download the source first. And remember the lossless promise only protects quality from this point forward: if your goal is genuine high-fidelity audio, you need a source that was lossless to begin with (an uncompressed AVI, a CD rip, or a hi-res master). When the AVI's audio is already lossless PCM, FLAC is a perfect fit and typically shrinks it to 50–70% of the original size; for an uncompressed copy instead, use AVI to WAV.

Frequently Asked Questions

Will converting AVI to FLAC improve my audio quality?

No. FLAC is lossless, which means it preserves exactly what it is given without adding new loss — but it cannot recover quality that was already discarded. If your AVI holds MP3 or AC-3 audio (most do), the FLAC will sound identical to that lossy source, not better. FLAC only guarantees no further degradation.

Why is my FLAC file larger than the original AVI audio?

Because lossy codecs like MP3 and AC-3 store a compact approximation, while FLAC stores a lossless representation of every decoded sample. Re-encoding a 192 kbps track to FLAC can easily multiply its size several times over. FLAC's 50–70%-of-original figure is measured against uncompressed PCM, not against an already-compressed lossy stream.

What audio do AVI files actually contain?

AVI is a 1992 Microsoft container that interleaves a video stream with an audio stream. That audio is most often MP3 or AC-3, though AVI can also carry uncompressed PCM. The codec inside your specific file determines whether the FLAC you get is a faithful copy of lossless audio or just a lossless wrapper around lossy audio.

Does the compression level affect sound quality?

No. The Compression level slider (1–12) only changes encode time and final file size. Every level is mathematically lossless and decodes to bit-for-bit identical audio, so a level-12 file sounds exactly like a level-1 file — it is just smaller and took longer to make.

Is FLAC a good choice for archiving the audio?

If the source audio is lossless, yes — FLAC is a 2001 format (formally specified as IETF RFC 9639 in December 2024) designed for exactly this: it compresses PCM to roughly 50–70% of its size with no quality loss and supports up to 32-bit samples and 8 channels. Archiving lossy AVI audio as FLAC works too, but you are preserving a lossy source losslessly rather than gaining fidelity.

Will the FLAC play everywhere my AVI did?

Not identically. FLAC plays in VLC and foobar2000 and natively in Chrome 56+, Firefox 51+, Edge 16+, and Safari 13+, but some older or stock players lack a FLAC decoder. In our testing, a FLAC made from a stereo 48 kHz AVI audio track opened and played correctly in VLC and in current Chrome without any extra codec.