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ReplayGain
ReplayGain tags let players play every track at the same loudness. FluentDL measures each track and writes the tags. It doesn't change the audio.
ReplayGain arrives in the first release after 3.8.0.0.
FluentDL uses ReplayGain 2.0, which measures loudness with ITU-R BS.1770 and targets -18 LUFS. rsgain and foobar2000 use the same method.
Track gain brings every track to the same loudness, which suits shuffle and mixed playlists. Album gain gives every track on an album one shared gain, which keeps the volume differences within the album.
| Track | Loudness | Track gain | Album gain |
|---|---|---|---|
| Track 1 | -22.0 LUFS | +4.00 dB | +4.90 dB |
| Track 2 | -30.0 LUFS | +12.00 dB | +4.90 dB |
| Track 3 | -21.0 LUFS | +3.00 dB | +4.90 dB |
FluentDL can write both, and your player decides which one to use. In MusicBee this is under Controls > Replay Gain, and in foobar2000 under Preferences > Playback.
The gain adjustment adds the same number of dB to every gain. A negative value such as -5 dB makes everything quieter, which leaves room to raise quiet tracks without clipping. The adjusted gain goes into the tags, so use one value for your whole library.
A positive gain can push a track's loudest point past full scale, which distorts. Track 2 above peaks at -9 dBFS, so its +12 dB gain takes it to +3 dBFS.
Any of these prevents it:
- Let your player use the peak tags that FluentDL writes. foobar2000 can do this.
- Turn on Prevent Clipping. It lowers a positive gain until the peak reaches 0 dBFS, so that track plays quieter than the rest.
- Use a negative gain adjustment.
- Add tracks and press ReplayGain. The dialog works on every track in the list.
- Choose your options. Hover over one to see what it does.
- Press Analyze, check the results, then press Write tags.
Write tags only saves files whose values changed. Turn on Skip tracks that already have ReplayGain tags to leave those tracks out of the analysis too. With album gain, an album is skipped only if all of its tracks have the tags.
After the analysis, each row has a badge for what Write tags will do to that file. New (green) means the file has no ReplayGain tags yet, Update (yellow) means some of its values change, and Up to date (grey) means there's nothing to write. On an Update row, the file's current value appears as Current under each gain that changes. Hover over a badge to see every value a write adds or changes. A warning icon marks tracks that would clip or couldn't be read. FluentDL groups tracks into albums by their album and album artist tags, and falls back to the folder when those are missing. Treat all tracks as one album gives the whole list one album gain instead. If a track on an album can't be read, the album's other tracks get track gain only, because album gain needs every track.
The preview panel shows a local file's track gain and album gain, if it has them.
These settings are under Settings > Downloads > ReplayGain.
| Setting | Default | Effect |
|---|---|---|
| Tag Downloads | Off | Writes track gain to each download. |
| Album Gain for Album Downloads | Off | Also writes album gain to whole albums downloaded from Search, if no track is missing. Albums added to the queue get track gain only. |
| Gain Adjustment | 0 dB | Also the starting value in the Local Explorer dialog. |
| Prevent Clipping | Off | Also the starting value in the Local Explorer dialog. |
FluentDL writes REPLAYGAIN_TRACK_GAIN, REPLAYGAIN_TRACK_PEAK, REPLAYGAIN_ALBUM_GAIN and REPLAYGAIN_ALBUM_PEAK. FLAC and Opus files get Vorbis comments, MP3, WAV and AIFF files get ID3v2 tags, and M4A files get iTunes tags. Some formats, such as WebM, can't store ReplayGain tags, and the dialog reports those tracks as failures. Other loudness tags, such as R128_* and iTunNORM, stay as they are. Apple Music ignores ReplayGain tags.
Everything sounds quieter. -18 LUFS is quieter than most modern releases. Turn up the volume, or raise the gain adjustment.
A few tracks don't match the rest. They probably have tags from another tool or another gain adjustment. Run ReplayGain on them again.