Speaker 1: Welcome to brain Stuff from how stuff works dot com
Speaker 1: where smart Happens. Hi. I'm Marshall Brain with today's question,
Speaker 1: what are MP three files and how do they work?
Speaker 1: A CD stores music using forty four thousand, one hundred
Speaker 1: digital samples per second, sixteen bits per sample, and two
Speaker 1: channels for stereo sound. This means that a CD stores
Speaker 1: about ten million bytes or ten megabytes of data per
Speaker 1: minute of music on a CD. A three minute song
Speaker 1: therefore requires thirty megabytes of data on a CD. If
Speaker 1: you've ever tried to download files on the Internet, you
Speaker 1: know that thirty megabytes is a big file. If you're
Speaker 1: using a slow connection to connect to the Internet, thirty
Speaker 1: megabytes of data would take several hours to download. MPEG
Speaker 1: stands for the Moving Picture Experts Group, and they've developed
Speaker 1: compression systems used for video data. For example, DVD movies,
Speaker 1: h d TV broadcasts, and ds A satellite systems all
Speaker 1: use MPEG compression to fit video and movie data into
Speaker 1: smaller spaces. The MPEG compression system includes a subsystem for
Speaker 1: compressing sound. It's called MPEG Audio Layer three, and we
Speaker 1: know it by its abbreviation MP three. MP three can
Speaker 1: compress a song by a factor of ten or twelve
Speaker 1: and still retain something close to CD quality. So a
Speaker 1: thirty megabytes sound file from a CD reduces to three
Speaker 1: megabytes or so an MP three. When you download the
Speaker 1: MP three file and play it, it sounds almost as
Speaker 1: good as the original file. If you wanted to, you
Speaker 1: could download an MP three file, expand it back to
Speaker 1: its original size, and then record it on a writable
Speaker 1: c D so you can play it in a CD player.
Speaker 1: All that you're doing is converting back and forth between
Speaker 1: different formats to make downloading easier. Do you have any
Speaker 1: ideas or suggestions for this podcast? If so, please send
Speaker 1: me an email at podcast at how stuff works dot com.
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