Why do archives demand FLAC yet suppliers still ship AAC stems?
Automation often keys off extensions and MIME types: FLAC passes, AAC or m4a bounces, even when the creative reality is AAC-only dailies from phones, Zoom, or podcast hosts. Searchers type aac to flac archive, lossless container policy, ffmpeg decode aac flac, DAM lossless intake, and honest rewrap because they need gate compliance, not magical high-frequency resurrection. FLAC is lossless relative to the decoded PCM samples, not relative to the pre-AAC air band that perceptual coding discarded—metadata and README lines must say sourced from AAC decode to keep auditors friendly. HE-AAC, AAC-LC, and parametric stereo paths decode with different channel maps—pilot three stems before you batch overnight. Sensitive dictation and uncleared samples do not become distributable just because the suffix now reads flac. Ai2Done keeps the lossless-container variant disciplined: read caps, write lineage sidecars, pilot DAM ingest, reconcile checksums, then migrate versioned keys instead of overwriting masters.
How to land AAC inside FLAC for archive intake without lying about fidelity
- Open AAC to FLAC, pick the lossless-container variant, confirm whether policy allows FLAC-from-lossy-decode, and read max upload size and duration limits.
- Export a pilot trio, import into the DAM sandbox, verify checksums, sample rates, and channel counts match catalog rows, and attach AAC-to-FLAC lineage JSON.
- Batch with versioned object keys, quarantine failures with explicit operator notes, and forbid silent skips—keep AAC masters until legal acknowledges receipt.