{# Per-pair FAQ synthesizer (png/faq_synth.py).
Branches on raster/vector, lossy/lossless, alpha-channel,
animation, and codec family so 831 conversion pairs ship
substantively different FAQ content. Documented in
~/seo/playbook/02-faq-synthesizer-pattern.md. #}
What does the AAC to FLAC audio converter do?
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AAC is already lossy, so converting to FLAC preserves the existing audio without further degradation, but it cannot recover detail lost in the original encode. FLAC is right if you plan to edit and resave without compounding compression artifacts.
Will the sample rate and channel layout be preserved?
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By default yes — stereo stays stereo, the original sample rate (44.1 kHz, 48 kHz, etc.) is carried through to the FLAC output.
Will the FLAC file be much larger than the source AAC?
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Yes — lossless audio is typically 5-10x larger than lossy audio at perceptually equivalent quality. Plan for ~10 MB per minute for FLAC versus ~1 MB per minute for high-bitrate AAC.
Will the FLAC be larger than the AAC?
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Yes — lossless containers store every byte. Expect the FLAC to be 3-8x the size of the AAC. The benefit is no further quality loss on editing or re-encoding.
Is there a file-size limit when converting AAC to FLAC?
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Anonymous uploads are capped at a generous default; signed-in free accounts get a higher cap, and Pro accounts have no per-file limit. Browser memory is usually the practical constraint long before our server-side limits kick in.
Can I batch-convert several AAC files to FLAC at once?
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Yes. Drop or pick multiple AAC files in one upload — the converter processes them in parallel and returns a ZIP of the FLAC results. There is no need to repeat the upload step per file.
What happens to my AAC files after the conversion?
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Uploaded files and FLAC outputs are auto-deleted after a short retention window. We do not inspect, share, or train on user files. Direct download links are time-limited and tied to your session.
What apps can play a FLAC file?
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FLAC plays in most music players, browsers, and media libraries. iTunes / Apple Music, VLC, Foobar2000, and phone media apps handle it natively.
Do I need to install software to convert AAC to FLAC?
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No. The converter runs entirely in your browser plus our cloud — no plugin, no install, no admin rights. It works on Windows, macOS, Linux, ChromeOS, iOS, and Android.
Do I need an account to convert AAC to FLAC?
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No. AAC to FLAC conversion is free and works without an account. Signing in unlocks higher file-size caps, batch history, and API access.
Is there an API for AAC to FLAC conversion?
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Yes. Every conversion this site offers is also exposed via a JSON API — see /api/ for endpoints, authentication, and rate limits. AAC to FLAC is one of the supported pairs.
What if my AAC fails to convert to FLAC?
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Failures are usually caused by corrupted source files or unsupported AAC variants. Re-export from the original app and try again; if it still fails, the contact page forwards the file to support so we can diagnose.