Gapless test set

One continuous tone, cut into separate files. Played without a gap it is one smooth sweep.

Each folder holds a sine sweep from 220 Hz up to 880 Hz and back, about 24 seconds at −20 dBFS, cut into 2 to 5 files at arbitrary sample positions, never near a zero crossing and, for FLAC, never on a block boundary, so every piece ends in a short block.

The right channel runs a quarter period ahead of the left, so a channel swap or a lost channel at a boundary is audible too.

MP3 is lossy and has no sample-exact length of its own: an MP3 player is gapless only if it reads the encoder delay and padding from the LAME header and trims them. Every piece here has one. A player that ignores it plays a few dozen milliseconds of silence at each boundary.

The -META folder is the same cut stuffed with what taggers leave in real files: cover art from 2 KB to 2 MB, lyrics, one or two ID3v2 tags in front of the audio, an APEv2 tag with its own cover and ID3v1 behind it. A player has to skip all of it, at the start and at the end of a file, without losing its place at the boundary.

How to listen

1. Copy the GAPLESS folder to the player.
2. Set play mode to normal (not shuffle or repeat track).
3. Open a folder and play 01, or hold play on the folder (or on GAPLESS itself to queue every set).
4. …
5. …
6. PROFIT