Data Transfer : Sound and Video Files

There are two related standards for storing and transferring video and music files. They are :

• MPEG File : MPEG files store video sequences in a highly compressed form. Compressing video makes it possible to store full length films on a single DVD and to view small videos over the Internet.
  
  
• MP3 File : MP3 files store music in a highly compressed form. In addition to the music itself an MP3 file can store information such as the name of the artist, song and album that the file was made from. Usually you can fit around 15 songs on a CD, but if the songs are stored in MP3 format it is possible to store 150. The MP3 system compresses music by removing unneccessary information such as sounds that a human would not hear from a recording. When you record an MP3 file you can choose the quality that you want to use for the recording. The higher the required quality, the more space the file will take up. A typical MP3 file containing one song will be about 4 megabytes in size. MP3 files can be played on home computers or portable MP3 players.

As MPEG and MP3 files are relatively small they can be transmitted quickly across the Internet. This has resulted in many people exchanging videos and music online. These are usually copyright, and downloading copyright material is illegal. The record producing industry in particular has suffered with record sales falling considerably as people illegally copy music for free.

Another standard for storing music files is MIDI :

• MIDI File : MIDI files store music. Unlike MP3 files which store the sounds made, a MIDI file stores information about the musical notes that make up a piece of music. MIDI files can be recorded by playing on a MIDI Instrument and played back on either a MIDI Instrument or through speakers connected to a computer. As a MIDI file contains information about the notes played in a piece of music it is possible to modify MIDI recordings easily. For example you could record a MIDI file on a keyboard then listen to it played back on a harp, change the order the notes are played in or the pitch of the music.

GCSE ICT Companion 04 - (C) P Meakin 2004