Você pode obter todas as metatags ID3, incluindo a taxa de bits de exiftool :
ExifTool is free software used for reading, writing, and manipulating image, audio and video metadata. It is platform independent and is both a Perl library and command-line application. ExifTool is a popular tool to incorporate into different types of digital workflows and supports many types of metadata including Exif, IPTC, XMP, JFIF, GeoTIFF, ICC Profile, Photoshop IRB, FlashPix, AFCP and ID3, as well as manufacturer-specific metadata of many digital cameras.
Starting with version 7.79 (June 20, 2009), ExifTool added read/write support for Adobe InDesign files (.IND, .INDD, .INDT), and ability to geotag with KML files.
O comando que você quer é:
$ exiftool -AudioBitrate File.mp3
Audio Bitrate : 128000
A execução do comando sem argumentos gera todas as tags. É multi-plataforma e funciona para a maioria dos tipos de multimídia. Isto está disponível através do pacote libimage-exiftool-perl no Ubuntu.