When referring to audio, bitrate is a measurement of bits per second that audio distributes. The sound quality will improve as the bitrate improves. For example, MP3 files with a bitrate of 128 kbps are more likely to sound better than MP3 files with a bitrate of 64 kbps. However, the 128 kbps MP3 file is going to be larger in size.
There are many software programs available that allow users to convert high bitrate audio files to a lower bitrate. One such program is Windows Media Player, available for free in the Microsoft Windows operating system. These software programs are especially useful for users who want to store audio files on MP3 players with limited space.