For a stereo signal it’s 292162.5 bits/sec. ATRAC compresses 512 incoming 16 bit samples (1024 bytes) into one ATRAC “sound group” (212 bytes) giving an audio compression ratio of 4.83:1. Here is the math: 44100 samples/sec (incoming single channel rate) / 512 samples/soundgroup (giving 86.133 soundgroups/sec/channel) * 2 channels (giving 172.266 stereo soundgroups/sec) * 212 bytes/soundgroup (giving 36.5K stereo bytes/sec) * 8 bits/byte (giving stereo bits/sec) = 292162.5 bits/sec. ATRAC3 (used in MDLP) runs at 132kbps (LP2) and 66kbps (LP4). See the MDLP FAQ for further details.