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This is an example of the compression ratios of MP3. There is some math, but don't worry, it won't be on the quiz. Wave files (.WAV) stored on a hard drive in a format very similar to CD audio. Wave files can have a variety of sample rates, sample size and mono or stereo CD audio is Always 44,100 samples per second / 16 bit samples / stereo. That means there are 88,200 samples recorded every second. because each sample is 2 bytes (16 bits) the file will contain 176,400 bytes of data for every second of music. The file will have a short header at the begining that tells the program playing how long the file is (in bytes), sampling rate, channels (1 for mono 2 for stereo), and the sample size (8 or 16 bit).
MP3 files are rated in Kbits (1024) per second. To figure out the bytes per second on a 128K file:
128k=(128 X 1024)= 131,072 bits per second
131072 bits per second / 8 = 16384 bytes per second
Redbook (CD Audio) & Wave files (44,100 / 16bit / stereo)
176,000bytes/second
176,000 Bytes per second / 16384 Bytes per second = 10.7
So the actual compression ratio for 128kps MP3s is 10.74 to 1.
A 256K files is compressed 5.37 to 1. etc
