[FFmpeg-user] Output file size

[Rodolfo Medina]

Hi all.

I'm adding id3 tags to a 208M mp3 file, with:

 $ ffmpeg -i input.mp3 -metadata artist="Caterina Pontrandolfo Quartett" -metadata album="concerto di Fonte Avellana" -metadata genre="popular" -metadata composer="tradizione lucana" output.mp3

.  Now, the output.mp3 is only 83M.  Why this?  Does it mean a quality loss?
How can I avoid it?  How can I have output.mp3 the same size as input.mp3?
Adding `-qscale 0' does not help.

Thanks for any help,

Rodolfo