YouTube to FLAC

How FLAC conversion works

The server decodes YouTube's Opus or AAC stream to PCM and stores it in FLAC, which compresses without loss. Everything that was in the YouTube stream is kept; nothing that was removed by YouTube's encoder comes back.

1. 1
   Paste the video link

   Any single public video.

2. 2
   Choose FLAC as the format

   The hint explains that the source is lossy. Chapter embedding is unavailable for FLAC, so use Split chapters if you need tracks.

3. 3
   Fetch

   FLAC files are larger and take longer to prepare than MP3, since the temporary output is uncompressed PCM.

4. 4
   Save and, if you like, convert to ALAC

   Apple devices prefer ALAC. The local FLAC to ALAC tool converts losslessly in your browser.

When FLAC is the right choice: you plan to edit, trim, normalize or remix the audio and want to avoid a second lossy encode; you keep an archive and want the closest copy to the source; your workflow standardizes on FLAC. When it is not: you just want to listen, in which case Opus or M4A gives the same quality at a fraction of the size. Free FLAC covers single videos up to 60 minutes. With a Supporter Pass, FLAC is capped at two hours and 2 GiB per item. Use only videos you own or have permission to download.

What is actually inside a YouTube FLAC

YouTube never serves a lossless copy of what creators upload. Each video's sound is served as a lossy stream: usually Opus at about 130 to 160 kbps and 48 kHz, sometimes AAC at about 128 kbps and 44.1 kHz. AudioFetcher takes the best stream available, decodes it once and writes 16-bit FLAC at the source sample rate. The FLAC holds exactly the samples YouTube's own player would produce, nothing more.

Two things follow. A spectrogram of the file still shows the source's limits, often a sharp high-frequency cutoff, so tools like the fake FLAC checker will correctly report a lossy origin. And because no further information is thrown away, every later cut, fade or export starts from the cleanest copy you can get.

When FLAC is worth it, and when it is not

• Worth it: you will edit the audio in a DAW or audio editor and export again, so you avoid stacking a second and third lossy encode.
• Worth it: your library, archive or music server is all FLAC and you want one consistent format.
• Worth it: a tool or device you use reads FLAC but not Opus.
• Not worth it: everyday listening. Opus or M4A sound identical at about a fifth of the size.
• Not worth it: trying to make a song sound better. No format can restore what YouTube's encoder removed.

FLAC file size per minute

FLAC sizes vary with the content: speech and quiet acoustic music compress well, loud and dense mixes much less. The audio inside is the same in every row except MP3, which is re-encoded.

Where FLAC plays: phones, computers, editors and cars

• iPhone and iPad: the Files app and VLC play FLAC, but the Music app will not import it. For Apple Music, convert it with the local FLAC to ALAC tool; ALAC is Apple's lossless format and holds the same audio.
• Android: built-in support; the Files app and nearly every music player open it.
• Windows 10 and 11: Media Player plays FLAC natively, as do VLC, foobar2000 and MusicBee.
• Mac: QuickTime Player and Quick Look play FLAC; the Music app does not, so use ALAC there too.
• DAWs and editors: Audacity, Reaper, Ableton Live and FL Studio import FLAC directly. GarageBand, iMovie and some video editors do not; give them a WAV instead (YouTube to WAV).
• Car stereos: newer USB head units often list FLAC among supported formats, older ones read only MP3. Check the manual before filling a USB stick; when in doubt, use MP3.

Common FLAC problems

• The video is over 60 minutes: free FLAC stops at 60 minutes. A Supporter Pass or Day Pass allows FLAC up to 2 hours (2 GiB) per video; for longer recordings, Opus or M4A go up to 12 hours with a pass.
• It takes longer than MP3: the server writes uncompressed audio before compressing it, and the download is several times larger.
• A checker calls it fake lossless: expected, and honest. The source is lossy; FLAC only stops further loss.
• Artist, album or artwork missing: cover art embedding and the tag editor are MP3 features. Add artist, album and cover to the FLAC with a desktop tagger such as Mp3tag or foobar2000.
• No chapter markers: use Split chapters to get one FLAC per chapter.

Related AudioFetcher guides