WEBVTT - What are MP3 files and how do they work

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<v Speaker 1>Welcome to brain Stuff from how stuff works dot com

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<v Speaker 1>where smart Happens. Hi. I'm Marshall Brain with today's question,

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<v Speaker 1>what are MP three files and how do they work?

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<v Speaker 1>A CD stores music using forty four thousand, one hundred

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<v Speaker 1>digital samples per second, sixteen bits per sample, and two

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<v Speaker 1>channels for stereo sound. This means that a CD stores

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<v Speaker 1>about ten million bytes or ten megabytes of data per

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<v Speaker 1>minute of music on a CD. A three minute song

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<v Speaker 1>therefore requires thirty megabytes of data on a CD. If

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<v Speaker 1>you've ever tried to download files on the Internet, you

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<v Speaker 1>know that thirty megabytes is a big file. If you're

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<v Speaker 1>using a slow connection to connect to the Internet, thirty

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<v Speaker 1>megabytes of data would take several hours to download. MPEG

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<v Speaker 1>stands for the Moving Picture Experts Group, and they've developed

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<v Speaker 1>compression systems used for video data. For example, DVD movies,

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<v Speaker 1>h d TV broadcasts, and ds A satellite systems all

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<v Speaker 1>use MPEG compression to fit video and movie data into

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<v Speaker 1>smaller spaces. The MPEG compression system includes a subsystem for

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<v Speaker 1>compressing sound. It's called MPEG Audio Layer three, and we

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<v Speaker 1>know it by its abbreviation MP three. MP three can

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<v Speaker 1>compress a song by a factor of ten or twelve

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<v Speaker 1>and still retain something close to CD quality. So a

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<v Speaker 1>thirty megabytes sound file from a CD reduces to three

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<v Speaker 1>megabytes or so an MP three. When you download the

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<v Speaker 1>MP three file and play it, it sounds almost as

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<v Speaker 1>good as the original file. If you wanted to, you

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<v Speaker 1>could download an MP three file, expand it back to

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<v Speaker 1>its original size, and then record it on a writable

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<v Speaker 1>c D so you can play it in a CD player.

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<v Speaker 1>All that you're doing is converting back and forth between

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<v Speaker 1>different formats to make downloading easier. Do you have any

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<v Speaker 1>ideas or suggestions for this podcast? If so, please send

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<v Speaker 1>me an email at podcast at how stuff works dot com.

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<v Speaker 1>For more on this and thousands of other topics, go

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<v Speaker 1>to houstaff works dot com