Convert AAC to FLAC — Free Online Converter
Convert Advanced Audio Coding (.aac) to Free Lossless Audio Codec (.flac) online for free. Fast, secure audio conversion with no watermarks or registr...
2M+ файлів конвертовано
Довіра тисяч користувачів
Безпечна передача
Завантаження зашифровані через HTTPS
Конфіденційність передусім
Файли автоматично видаляються після обробки
Без реєстрації
Почніть конвертацію миттєво
Працює всюди
Будь-який браузер, будь-який пристрій
Як конвертувати
Upload your .aac file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .flac file when it's ready.
About AAC to FLAC Conversion
AAC delivers perceptually transparent audio through lossy compression, typically at 128-256 kbps. FLAC (Free Lossless Audio Codec) stores audio with perfect bit-for-bit accuracy while achieving 50-70% compression versus raw PCM. Converting AAC to FLAC decodes the lossy AAC data and re-encodes it losslessly, producing a file that preserves every sample the AAC decoder outputs. This is commonly done for archival purposes or to prepare files for workflows that require lossless input.
Why Convert AAC to FLAC?
Lossless audio editors and mastering chains expect FLAC or WAV input. If you apply effects to an AAC file and re-export as AAC, you compound lossy artifacts with each generation. Converting to FLAC first gives you a lossless working copy that survives unlimited editing cycles without further degradation. FLAC is also the standard archival format on Linux and Android, supported natively without extra software.
Common Use Cases
- Archiving an AAC music collection in a lossless format recognized by media servers like Plex and Jellyfin
- Preparing AAC recordings for editing in Audacity or Adobe Audition where lossless input is preferred
- Converting iTunes AAC purchases to FLAC for playback on Android or Linux systems
- Creating a lossless backup of voice recordings before applying noise reduction or normalization
- Building a FLAC library for high-fidelity playback through a USB DAC
How It Works
FFmpeg decodes the AAC stream to PCM, then encodes using the FLAC encoder at a configurable compression level (0-12, default 5). Higher compression levels produce smaller files but take longer to encode — the decoded audio is identical regardless of compression level. Output sample rate and bit depth match the source. Metadata from the AAC container transfers to FLAC's Vorbis comment tags.
Quality & Performance
The conversion is lossless from the point of decoding. Every PCM sample decoded from AAC is preserved perfectly in FLAC. However, information discarded by the original AAC encoder cannot be recovered. The FLAC file sounds exactly like the AAC source — no better, no worse — but it will not degrade further during editing or future transcoding.
Device Compatibility
| Device | AAC | FLAC |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Native | Partial |
| iPhone/iPad | Native | Partial |
| Android | Partial | Native |
| Linux | Partial | Native |
| Web Browser | No | No |
Recommended Settings by Platform
Spotify
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Apple Music
Resolution: N/A
Bitrate: 256 kbps
AAC format required
SoundCloud
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Podcast
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
Tips for Best Results
- 1Use FLAC compression level 5 for the best speed/size tradeoff — higher levels give diminishing returns
- 2Verify metadata transfer after conversion, especially album art and track numbers, since tag systems differ between M4A and FLAC
- 3If storage space is tight, remember that FLAC is still 50-70% smaller than raw WAV while being fully lossless
- 4Pair FLAC output with a media server like Plex or Jellyfin that can transcode on-the-fly to AAC for mobile streaming
Related Conversions
AAC to FLAC is the go-to conversion when you need a lossless, editable, archival copy of compressed audio. The file will be larger but immune to generation loss, making it ideal for long-term storage and professional workflows.