Você leu man mp3info
? Diz, em parte:
-p "FORMAT_STRING"
Print MP3 attributes according to FORMAT_STRING. FORMAT_STRING is similar to a printf(3) format string in that it is printed verbatim except for the
following conversions and escape sequences. Any conversion specifier may optionally include the various alignment, precision, and field width modifiers
accepted by printf(3). See the EXAMPLES section below for examples of how format strings are used in mp3info.
Conversion Specifiers
%f Filename without the path [string]
%F Filename with the path [string]
%k File size in KB [integer]
%a Artist [string]
%c Comment [string]
%g Musical genre [string]
%G Musical genre number [integer]
%l Album name [string]
%n Track [integer]
%t Track Title [string]
%y Year [string]
%C Copyright flag [string]
%e Emphasis [string]
%E CRC Error protection [string]
%L MPEG Layer [string]
%O Original material flag [string]
%o Stereo/mono mode [string]
%p Padding [string]
%v MPEG Version [float]
%u Number of good audio frames [integer]
%b Number of corrupt audio frames [integer]
%Q Sampling frequency in Hz [integer]
%q Sampling frequency in kHz [integer]
%r Bit Rate in kbps (type and meaning affected by -r option)
%m Playing time: minutes only [integer]
%s Playing time: seconds only [integer] (usually used in conjunction with %m)
%S Total playing time in seconds [integer]
%% A single percent sign