YouTube streams audio using lossy codecs:
Even if you extract the audio with yt-dlp (or similar tools) and convert it to .flac, you cannot recover data that was already discarded during YouTube’s encoding. The result is a large FLAC file containing lossy-source audio — no better than the original AAC/OPUS stream, just bigger.
To understand why "YT FLAC" is an oxymoron, you need to understand how YouTube processes audio. yt flac
When a creator uploads a WAV or FLAC file to YouTube, the platform transcodes it. YouTube does not stream lossless audio. Here is the current hierarchy of YouTube audio quality:
Because the source audio has already lost data during YouTube’s compression, converting that stream to FLAC is technically upsampling. You are increasing the file size without adding any missing sonic information. YouTube streams audio using lossy codecs :
The Spectrum Test: If you analyze a true FLAC file in software like Spek (a spectral analyzer), you will see frequencies reaching up to 22.05 kHz (the Nyquist limit for CD audio). If you analyze a "YT FLAC," you will see a hard cut-off at roughly 16 kHz to 18 kHz – a clear sign of lossy compression.
This is a command-line tool (a fork of the popular youtube-dl). It is the most powerful downloader available. Even if you extract the audio with yt-dlp
No – YouTube detects downloaders by IP, not by logged-in account. However, aggressive downloading (thousands of videos per day) can get your IP rate-limited. Use a VPN if archiving large volumes.