MP3 - an explanation
Well the following is from my MP3 addicted neigbour. I hope you understand it more than I want to.
James, Please explain it as though I know nothing.......
MP3, this is basically a standard for encoding music. It is based on the idea that most of the data that comprises an Audio CD is either sound you won't miss if it is absent, or error correction data, which is why a scratched audio CD can still play properly most of the time due to the massive redundancy incorporated into the audio standard called WAV. The WAV standard has lots of setups but CDs store the music sampled at 44Khz and streamed to the CD player as data at 1024 Kbps (kilobits per sec). This produces very big files when stored on a computer, a 3 minute track is typically 30-40 Megabytes making an album about 600 Megabytes (or a fullish CD - 650Megabytes). MP3 format is typically 44khz sampling but the data is streamed at 160 Kbps (CD quality in MP3 format) thefore you have a much much smaller file, typically 3 or 4 Megabytes for a 3 minute track. "Where did all the extra data go?" I hear you cry. It is thrown away.
Basically when you encode a normal audio track as an MP3 audio track the MP3 converter parses the audio track and compresses it in a lossy fashion (by throwing some of the music data, and all of the redundancy data, away). E.g. an Audio file encoded as an MP3 at 160Kbps will retain more of the original data (and sound a bit more full - you'd have to hear the difference) than an audio file encoded at 128Kbps. The lower the bit rate, the less good it sounds. I cannot tell the difference once you increase the bit rate above 192Kbps up to 1024kbps (audio CD standard quality). However, complicated music such as classical does sound less good when you encode it at 160kbps instead of 192kbps. All other music is fine at 160kbps. The slight (relative to your experience I suppose) complication is that the algorithm used to encode the music from CD to MP3 makes a difference. Clear as Mud?
2) How do you record MP3 onto CD - namely are there variable speeds and or competeing programmes?
That depends. If you want to create an audio CD that will play in a normal CD player then before you write the audio files onto a cd you have to convert the MP3s back to WAV format (the format normal audio CDs use). If you want a CD full of MP3s which will play in a MP3 CD player (you can fit some 70 -90 tracks on one, as opposed to 20 on a 700Megabyte CD using WAV) then usually you just burn the MP3s onto the CD.
Competing programmes? Certainly. I use a free one which uses the encoding algorithm I prefer called LAME 2. An older one is called Blade. There may be newer ones.
Is MP3 a fixed standard or do other programmes give better or worse performance in this area?
Tell me how and why you chose what you did?
MP3 is a fixed standard in as much as a car is a fixed standard. Basically an MP3 is a way of laying out a music file, not much more, just as a car is a description of a certain kind of vehicle.You can get all types of elaboration and also the reverse, a dawoo matiz all thw way to a Maybach Zeppelin - and some elements will not always function unless they are played on compatible programmes, but thats a nightmare we like to pretend doesnt exist.
The programme I use allows you to encode MP3s from an Audio CD at about 10 speed, i.e. for a 60 minute album it would take six minutes. Bascially the faster your CD drive, the quicker you can encode the music as the CD drive streaming it to your harddisk is the bottleneck (if you have a 3Ghz processor that is, on a slower processor it can only encode it as fast as it can process it). Some commerical programs claim they can encode faster, who knows, some do, some doent, but encoding arguably degrades at higer speeds - which it should not but is pricipally a compatibility issue. It is a concern if you have a lot of cds to encode and you are impatient I suppose. 6 minutes a CD is quick enough for me.
3) Why would I want it? (other than the fact the Car head unit will play MP3)
You can fit many more music files on your media when stored as MP3. Whether or not you want more music files at your finger tips is your choice. I have about 60 Gigabytes of MP3s, equal to some 13,000 tracks available to me over my home network whenever I want to listen to them. How many do I listen to? Probably 1 a month. If you want to store lots of music efficiently then it is an excellent way of keeping lots of music in a tiny space. Does it sound as good as the original? No. Can you tell the difference? Sometimes. It really depends on how lossy the compression is, you choose that by deciding what bit rate to use when encoding the files.
4) Why is MP3 a standad?
It is NOT an audio standard like Stereo, Dobly A, B or C. It is a way of storing audio data which can be read and played by an MP3 player. Just as ISO 9660 or Joilet are standards for storing computer data on CDs.This means it will not always work on all systems, but should on most-theoretically!