We can see what formats are acceptable by typing: ffmpeg -formats
BATCH MP3 BITRATE CONVERTER FREEWARE INSTALL
Give this a try: sudo apt-get install ffmpeg Especially note the VBR mapping table marked 'LAME Bitrate Overview'.
We can see what formats are acceptable by typing: ffmpeg -formats
Give this a try: sudo apt-get install ffmpeg Especially note the VBR mapping table marked 'LAME Bitrate Overview'.