Bit Rate

Bit Rate is the number of bits per second required to store or transport audio.

For uncompressed audio, it's the Sample Rate multiplied by the bit depth and the number of channels. For example, CD audio is 44,100 samples per second × 16 bits × 2 channels = 1,411.2 kbps. Compressed formats like MP3 or AAC get much lower bit rates, like 128 or 256 kbps.