Bit rate refers to the amount of information that can pass through in a data stream per second. You may have seen audio files described as “128–Kbps MP3” or “64–Kbps WMA.” Kbps stands for “kilobytes per second,” so higher numbers mean more data: 128–Kbps MP3 audio files contain twice the amount of data and take up twice as much space as 64–Kbps WMA files. (In this case, though, the two files sound identical. Why? Some file formats use data more efficiently than others, and a 64–Kbps WMA file has the same sound quality as a 128–Kbps MP3 .) The important thing to understand is that the higher the bit speed, the larger the amount of information, the more processing it takes to decode that information, and the more space the file needs to take up.

Choosing the appropriate bitrate for your project depends on your playback goals: if you want to play the VCD you created on a DVD player, the video must be 1150 Kbps and the audio must be 224 Kbps. A typical 206 MHz Pocket PC supports MPEG video at up to 400 Kbps—any playback beyond this limit causes glitches.

There are three different forms of bit rate:

VBR (Variable Bitrate) dynamic bit rate means that there is no fixed bit rate. The compression software determines the use instantly based on the audio data during compression. What is the bit rate? This is based on quality and file size. The recommended encoding mode is;

ABR (Average Bitrate) average bit rate is an interpolation parameter of VBR. LAME created this encoding mode in response to the poor file volume ratio of CBR and the variable size of files generated by VBR. ABR is within the specified file size, with every 50 frames (30 frames approximately 1 second) as a segment. Low-frequency and insensitive frequencies use relatively low traffic, and high-frequency and large dynamic performance use high traffic. It can be used as VBR and CBR. a compromise choice.

CBR (Constant Bitrate) means that the file has a bit rate from beginning to end. Compared with VBR and ABR, the file size it compresses is very large, and the sound quality will not be significantly improved compared to VBR and ABR