Guest | Media Streaming
What is meant by Audio Compression ?
An audio file in its purest uncompressed form is a wave file (file extension .wav). In particular a .wav file described as 16-bit PCM uncompressed 44.1KHz 2-channel stereo is equivalent to the contents of an audio track from an audio cd. It is also what most soundcards output. Such an uncompressed wav file occupies approximately 10MB of space per minute of audio. So a typical 4 minute song will be 30MB, much too big a file for using on the web, especially if all 40MB have to be downloaded and played in 4 minutes. Clearly that's not a good format to use on the web, even for high-speed internet users.
If we are compressing the above file to mp3 format, its compression scheme can reduce an audio source to just one-tenth of its original size. For instance, four minutes of high-quality music in WAV format requires 40 MB of disk space; as an MP3, the same file weighs in at just 3.5 MB! Read more about compression methods for audio formats. wma is a popular alternate choice for audio compression. Real format also used in few websites.
The choice of mp3 or wma can be based on this simple rule of thumb: for hi-fi audio, at 128kbps and higher, mp3 is a very good format. It is however only recommended for ultra-high speed internet connections. At lower bitrates, wma offers better quality than mp3 down to the lowest bitrate possible. It can be said that a wma at bitrates from 20kbps to 48kbps is roughly equivalent in quality to an mp3 double that bitrate (thus double the file size).
The mp3, wma and compressed wav formats will be playable through the default player (usually Windows Media Player) when embedded in a web page. Real Audio will be played through real Player.
The mp3 and wma formats are stated in terms of bits, bitrate, frequency and channels. The Real Audio format (.ra, .rm) are stated in terms of audiences.
