Lower the bitrate, downmix to mono, or move to a modern codec that sounds better at the same size.
—
80
Resize
50
Encoder detail
6
fastzopfli
256
28
0 lossless51 tiny
The largest saving available.
50
Speed, audio and advanced
8
0 smallest13 fastest
128
96
Advanced
8
Nearly all of the saving comes from the images inside.
150
75
Advanced
50
aggressivegentle
Advanced
14
coarsefine
0 merges only exactly equal vertices. A small value also closes hairline cracks left by CAD exporters.
Geometry only — texture coordinates,
materials and vertex colours are not carried through. Decimating a
UV-mapped mesh correctly is a much harder problem, and mangling your
UVs quietly would be worse than leaving them alone.
12
6
Advanced
ZIP and 7z. 7z encrypts the file list too.
What actually shrinks MP3 files
Opus at 96 kbps is generally transparent for music and beats MP3 at 192 kbps; for speech it is transparent far lower still.
Re-encoding a lossy file always loses a little more. If you have the original, start from that.
The preview plays an eight-second clip next to the same moment of the original, so you can actually hear the difference before deciding.