Audio Compressor
Opus, AAC, MP3 and FLAC, encoded as variable bitrate where that is available and normalised to the EBU R128 target so the result is not merely smaller but correctly loud. Nothing is uploaded
or click to choose · mp3, m4a, wav, flac, ogg, aac, opus, mkv, mp4, webm
Why is Opus the default?
Opus is a perceptual codec designed a decade after AAC and MP3 and it wins at every bitrate — at 96 kbps it is roughly where MP3 was at 192 kbps. The gap narrows above about 160 kbps and inverts: a 320 kbps MP3 can beat a 256 kbps Opus. Below 128 kbps there is no contest, which is why Opus is the default and why the bitrate menu changes with the format.
What does loudness normalisation actually do?
Two encodes of the same music at the same bitrate can differ in perceived loudness by several decibels, because encoders are inconsistent about it and mastering varies. EBU R128 measures integrated loudness and applies a single gain so the result lands on a known target. That is why streaming services normalise: without it, half your catalogue is quiet and half clips. It is a gain change, so it is lossless with respect to the audio — only the volume moves.