Audio format comparison
MP3 vs FLAC
FLAC stores audio losslessly — every bit of the source is preserved. MP3 throws away ~90% of the source data in exchange for ~10x smaller files. For most listening, MP3 at 256-320 kbps is perceptually indistinguishable from the source. For archival, mastering, or audiophile playback, FLAC is the only correct answer. YouTube doesn't serve FLAC — every YouTube audio is already lossy (AAC), so "downloading as FLAC" gives you a lossless container around a lossy file.
Side-by-side
| Feature | MP3 | FLAC | Winner |
|---|---|---|---|
| Quality | Lossy (some quality discarded) | Lossless (bit-perfect) | FLAC |
| File size (1 hour audio) | ~50-100 MB at 192 kbps | ~250-400 MB | MP3 |
| Universal device support | Yes | Yes on modern hardware | MP3 |
| Streaming-friendly | Yes (low bandwidth) | High bandwidth required | MP3 |
| For YouTube source | Requires transcode from AAC | Pointless — source is lossy AAC | MP3 |
| For mastering / archive | Inadequate | Standard format | FLAC |
MP3 wins on
- Universal compatibility.
- ~10x smaller files than FLAC.
- Streams over slow connections.
- Sufficient quality for typical listening.
FLAC wins on
- Lossless — perfectly reconstructs the source.
- Archival-grade for master files.
- Studio-friendly format.
- Royalty-free, open standard.
Verdict
For YouTube downloads: don't pick FLAC. YouTube's source audio is already lossy AAC — wrapping it in FLAC doesn't restore lost information. Save as m4a (the source format) or MP3 (for universal compatibility). FLAC is the right answer when you have lossless source files (CD rips, studio masters, vinyl rips) — not for YouTube content.