Of Bits and Bytes |
by Gnomie Matt Gruett
MP3s can be encoded at a variety of different bit rates. The bit rate determines how many bits are used to store one second of audio in the MP3 format. Higher rates improve the quality of sound but you'll spend a longer amount of time downloading them, or need a faster internet connection to be able to stream them. Something to keep in the back of your mind when you are encoding your MP3s is which rates your player supports. Most computer software and new hardware players can handle just about any bit rate out there, but certain players might not handle every possible bit rate available so double check first.
The bit rate is the amount of data used every second. The rate is expressed as the number of kilobits per second (kbps). So a rate of 128 kbps means that roughly 128,000 bits are needed for one second of MP3 playback. Seems like a lot, but remember that this is in bits. Most of us are used to working with bytes (1 byte = 8 bits), which means that a 128 kbps rate only takes up 16 kilobytes (kB). Multiplying that by 60 seconds and 5 minutes results in a 5 minute 128 kbps MP3 file being only 4.8 megabytes.
This could already include stereo so you don't need to multiply this by two. But just because it's 128 kbps doesn't mean that it necessarily is stereo. When you encode MP3s, you can select whether you want the file to be mono, stereo, or joint stereo. Mono is only one channel, so if you are encoding a stereo WAV file, it gets combined into just one channel. Stereo is simply two discrete channels of audio within the MP3. But joint stereo is a bit trickier. Joint stereo takes advantage of the same principal that subwoofer/satellite speaker systems use. Our ears have a tougher time hearing stereo from lower frequencies. The result is that the lower part of a joint stereo MP3 is in mono and the upper half is in stereo. Neat trick, huh?
Full stereo kicks in at about 128 kbps. Trying to encode full stereo at a lower rate than 128 will hurt quality quite a bit. Joint stereo works well between 64 and 192. I find that anything higher than 192 you might as well do full stereo. This is not to say that stereo is only useful above 192. Stereo encoding at 128 can sound very good if you are willing to take the time to encode it. If you are in a hurry, joint stereo 128 is a good middle of the road.
VBR is yet another rate related term, which stands for variable bit rate. That means that the audio is encoded using a different rate throughout the file. The encoder picks a rate and then varies above and below that to encode the audio, depending upon how much space the encoder thinks it needs to represent the audio file.
Latest Windows Daily
Latest Digital Media
Latest Tech Specialist
Latest Audio Show
Latest Bits & Bytes
Please Tell A Friend
High-Tech Job Search
Chat With Gnomies
Visit The Forums
Join The Reboot
View Our Media Kit
Partnership Info
Watch The Webcams
Submit Some Stuff
Read Past Issues
Download X-Setup
Lockergnome MP3s
About Lockergnome
Our Privacy Policy
View More Options
Get Chris's Book
E-mail Jake Ludington
E-mail Adam Finley
Search Past Issues:
Find a High-Tech Job:
 |
| CLICK HERE TO ZOOM |
See The GnomeSTORE
Get Your GnomeSTUFF
This Week's Fonts
This Week's Themes
This Week's Screens
This Week's Icons
And now, I invite you to take a look at my complete collection of Garbage Pail Kids.
