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Compressing copies of CD tracks to use less disk space

A typical CD can hold several hundred megabytes (MB) of information. When copying CD tracks to your computer, you generally do not want to use as much disk space for the tracks as is available on the CD. To use less disk space, you can compress CD tracks when you copy them to your computer. However, some audio quality is lost when the track is compressed. The better the audio quality when a track is copied, the more disk space is required.

Windows Media Player automatically compresses CD tracks when you copy them to your computer; otherwise, one CD would use hundreds of megabytes on your computer.

The following file formats are available for you to use when copying CD tracks:

Windows Media Audio. Tracks are copied using a constant bit rate which means that no matter how difficult it is to compress a section of music, the same compression is used throughout the track. Depending on the music, the audio quality may not be the same throughout the track. However, you have a better idea of how much space the track will use on your computer.
Windows Media Audio (variable bit rate). Tracks are copied using a variety of bit rates to compress the music as necessary. Using a variable bit rate enables the Player to use more compression for audio sections that are easy to compress, and more compression for audio sections that are harder to compress. The end result is a track that has a better audio quality throughout. Before a track is copied, there is no way to tell how much disk space will be used on your computer.
Windows Media Audio Professional. Tracks are copied using very little or no compression and require the most disk space per track. Each track could use anywhere from 206 to 411 MB of disk space per track. When you select this format, the audio quality slider is not available.

The following table shows the range of disk space used for different audio qualities available for the Windows Media Audio format:

Quality	Bit rate	Disk space per CD*
Smallest size	48 kilobits per second (Kbps)	22 megabytes (MB)
Small (CD quality)	64 Kbps	28 MB
Medium	96 Kbps	42 MB
Medium-high	128 Kbps	56 MB
High	160 Kbps	69 MB
Best quality	192 Kbps	86 MB

*Refers to the amount of disk space required if you copy an entire CD according to quality level.

The following table shows the range of disk space used for different audio qualities available for the Windows Media Audio (variable bit rate) format:

Quality	Bit rate	Disk space per CD*
Smallest size	40 to 75 kilobits per second (Kbps)	40 to 75 megabytes (MB)
Small (CD quality)	50 to 95 Kbps	22 to 42 MB
Medium	85 to 145 Kbps	37 to 63 MB
High	135 to 215 Kbps	59 to 94 MB
Best quality	240 to 355 Kbps	105 to 155 MB

*Refers to the amount of disk space required if you copy an entire CD according to quality level.

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Compressing copies of CD tracks to use less disk space

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