FLAC to AU — Format Comparison & Online Converter
Fast, instant FLAC to AU conversion. No signup required. Just drop your .flac file and get .au in seconds.
Batch Settings
お気に入りの音楽コレクション、特に高音質のFLACファイルを、ビジネスシーンでの利用や、あえてレトロな音質を求めるクリエイティブな場面でAU形式へ変換する必要はありませんか？ FLACはその豊かな情報量で音楽愛好家を魅了しますが、特定の古いシステムや、インターネットがまだ普及途上にあった頃の懐かしいサウンドを再現したい時、あるいは簡潔な音声メモを扱う際には、AU形式がそのシンプルな構造ゆえに重宝されることがあります。当社の変換ツールは、お客様の大切な音源を、音質劣化を最小限に抑えつつ、AU形式へとスムーズに橋渡しします。複雑な設定は一切不要。直感的な操作で、どなたでも簡単に、そして安心してご利用いただけます。あなたのデジタルライフを、より快適に、そして創造的にサポートするための第一歩として、ぜひお試しください。
- 古いプレゼン資料の音声ファイル
- 同人ゲームのレトロ風SE
- 社内研修用ナレーションの軽量化
日本では、特定の業務用音響機器や、インターネット黎明期のコンテンツ制作において、AU形式が現在でも稀に利用されることがあります。特に、古いシステムとの互換性が求められる場面でその存在感を放ちます。
About FLAC to AU Conversion
FLAC (introduced 2001) and AU are both audio formats, but they differ in important ways. FLAC is lossless audio compression — bit-for-bit identical to the original at roughly 50-70% of WAV size. AU is a widely used file format.
When you convert FLAC to AU, the goal is to convert between formats quickly. Converting FLAC to AU maintains high quality with CocoConvert's optimised encoder settings. Understanding these technical differences helps you choose the right format for your workflow.
Your FLAC file is decoded and re-encoded as AU. The conversion involves 4 steps: (1) your flac file is uploaded and validated, (2) the file is decoded (parsed into its raw data), (3) the data is re-encoded in au format, (4) the converted file is ready for download.
CocoConvert's converter handles the entire pipeline server-side using FFmpeg, Sharp, and qpdf — battle-tested libraries used by streaming platforms and enterprise tools. Files are encrypted in transit and deleted within 24 hours.
This conversion is ideal when you When you need a AU file. For the opposite direction, CocoConvert also supports AU to FLAC conversion.
How to Convert FLAC to AU
- 1
Upload .flac file
Select your FLAC file by dragging it to the upload zone or using the file picker. Batch upload is available for multiple files.
- 2
Choose .au
Set AU as the output format. The converter uses optimal settings based on the FLAC→AU conversion profile.
- 3
Convert
The server-side engine decodes your FLAC file and re-encodes it as AU. Processing time depends on file size and complexity.
- 4
Download result
Grab your converted .au file. Multiple output files can be downloaded together.
What Happens When You Convert FLAC to AU
Your FLAC file is decoded and re-encoded as AU.
Your FLAC file is uploaded and validated
The file is decoded (parsed into its raw data)
The data is re-encoded in AU format
The converted file is ready for download
Format Comparison
FLAC
.flac file
| Extension | .flac |
| MIME Type | audio/flac |
| Category | Audio |
AU
.au file
| Extension | .au |
| MIME Type | audio/basic |
| Category | Audio |
Should You Convert FLAC to AU?
When to Convert
- ✓When you need a AU file
Frequently Asked Questions
What is the difference between FLAC and AU?
FLAC is lossless audio compression — bit-for-bit identical to the original at roughly 50-70% of WAV size. AU is a widely used file format.
Does FLAC to AU conversion affect quality?
Converting FLAC to AU maintains high quality with CocoConvert's optimised encoder settings.
Which format has better compression, FLAC or AU?
FLAC uses lossless compression. AU is widely supported. The better choice depends on whether you prioritize file size or quality.
How long does FLAC to AU conversion take?
Most conversions finish in seconds. Larger files or complex audio content may take 10–30 seconds. CocoConvert processes files in parallel for batch jobs.
Is FLAC or AU better for long-term storage?
FLAC is better for archival since it's lossless.
Versions are pinned in our worker Dockerfile and re-built via CI on every change.