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DEL.ICIO.USPeeking behind the curtain of MP3
The Atlanta Journal-Constitution
MP3 players are as popular as free beer at Hooters.
The first question people have after getting an MP3 player, is “Where do I get MP3s?�
Over the next week or so we will discuss the legal and not-so legal ways of obtaining digital music.
While we see how my team of bosses react to the previous sentence, let’s try to get a handle on what an MP3 is.
In the early 1980s, the audio compact disc came into existence. They became popular because they were portable, durable and sounded great. The only problem with them was each song took up a lot of space, limiting each CD to about 20 songs max.
It took some high-powered geeks to fix this.
Geekboy’s History of the MP3
Once upon a time a team of smart Germans got together and, instead of invading France, decided to create a method of making large video and audio file sizes smaller.
Audio and video files needed to be smaller so they could be transmitted more easily over phone lines using modems, which, if anyone recalls, are as slow as molasses in a pre-global warming winter.
To prevent anyone from going to sleep, I will skip the technical details, but needless to say the scientists succeeded.
Their first release was called MPEG-1, and compressed audio and video, like that in a television broadcast. Not that you care, but MPEG stands for Motion Pictures Expert Group, the folks that set the standards for stuff like this.
Eventually, people migrated from slow modems to faster broadband connections and thus the vastly improved MPEG-2 came into being. Most DVDs are recorded in a slightly tweaked version of MPEG-2.
MP3 is a similar compression scheme without the video element. The scientists, who endlessly played Suzanne Vega’s “Tom’s Diner,� were trying to reduce the size of a music file, like those found on audio compact discs, without obvious loss of quality so you could fit more of them onto a hard drive, something every iPod owner appreciates.
How did they do it?
The simple answer is they threw out everything the human ear could not discern.
Digital music, like that on a CD, actually contains more information than the human ear can detect. MP3s basically eliminate all the extra information, making the file size much smaller.
How much smaller is an MP3 than the source music?
It depends.
The size of an MP3 file, and its audio quality, is determined by its “bit rate,� which is simply a measurement of how many packets of information are transmitted in a given period of time, usually per second.
The more bits per second, the better the song sounds, but the more space it will take on your hard drive. The songs on a CD are recorded at the bloated rate of 1400 kilobits per second.
Most listeners are quite happy with a bit rate of 128 kilobits per second, usually written as 128k.
A 128k MP3 is supposed to sound as good as FM radio, so that will likely suit most users. Other popular bit rates are 192k and 256k, which is supposed to sound as good as the CD itself.
A 128k MP3 is roughly a tenth as large as the original song, a 256k MP3 about a fifth as large.
I use 128k MP3s in portable devices, and so do most other people. Next week we will discuss how to acquire MP3s. Until then, let’s compare the various bit rates and see if you can tell a difference in quality.
The following links will fire up the opening few seconds of “Waters Partâ€? by Let’s Active, an old school band from North Carolina.
Can you tell the difference?
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Comments
Commenting is now closed for this entry.
By Ernest
January 26, 2006 02:24 PM | Link to this
Great information! I wondered this as I was attempting to convert a portion of a DVD to a file that could be played in Media Player. I recall one option enabled me to strip the video and only keep the sound. What you listed above helps me understand that.
By Chris
January 26, 2006 02:43 PM | Link to this
Nicely explained. Am in process of ripping cd collection to iTunes, so for me, your article is timely as well. And Lets Active! From back in the day… how about some Flat Duo Jets in the next entry?
By Doug
January 26, 2006 03:07 PM | Link to this
Great information for all the new iPod owners who got one of these gems for Christmas and don’t know what to do with it. Thankfully, Apple has made it easy to purchase legal downloads and organize music you already have.
It’s a new age, the music consumer is empowered, and these record company suits need to start adjusting to the new market instead of whining about their losses in CD sales. They could start by making all CDs retail at $9.99 or less, the same for which you can buy most online albums.
By Jex
January 26, 2006 03:16 PM | Link to this
You have no idea of how much I appreciate this. I have been feeling as if I fell asleep for 3 or 4 years and woke up to everyone gloating over these wonderful MP3 whatchamacallits. It was like they popped up out of nowhere and everyone had one or wanted one…except me. I wasn’t really sure what it was or what the big deal was. You have educated me and saved me much embarrassment. Thanks!
By bill
January 26, 2006 03:42 PM | Link to this
My wife is German and she has never considered invading France. Luxenburg, maybe. But I think you are typecasting.
By Mark Adkins
January 26, 2006 04:47 PM | Link to this
Let’s Active! Where did you find that? Great band from long, long ago…Where can I get it? Maybe you could include some Guadalcanal Diary or Arms Akimbo next time…
By Frank
January 26, 2006 06:03 PM | Link to this
Thanks much. I love the National Public Radio Science Friday MP3’s about science in our world.
By Alex
January 26, 2006 06:36 PM | Link to this
I never pay for online music, and you shouldn’t have to either.
By Jake
January 26, 2006 06:38 PM | Link to this
Good article. Explains some very technicle stuff very plainly.
On some tracks, you CAN tell a difference between 128 and 256. Sometimes a big difference. Same with 128 to 96, but 128 is a good medium between quality and harddrive space. As for acquisition, and I’m way ahead on this, go to archive.org. Bands and artists that let their fans records their live shows have their concerts posted there. Varying sound qualities, and few “major” artists, but some real gems. Read the site’s policy re copyright etc… but all seems on up and up.
By Faye
January 26, 2006 06:46 PM | Link to this
I received an MP3 from Bellsouth for transferring to their ISP with a 3 month free Napster to go. I downloaded a few songs, but now that my 90 days is over, the songs no longer play. The MP3 screen says to sync. What?
By Geekboy
January 27, 2006 09:01 AM | Link to this
Faye — Napster says you have to “Log in to Napster and connect your MP3 player to sync your track licenses.”
Sounds a bit onerous to me.