Unit 73 File Formats

Unit 73

File formats

Uncompressed:

WAV – waveform audio file. It is a Microsoft and IBM audio format. A WAV format is used on Windows systems for uncompressed audio.

AIFF – Audio Interchange File Format. AIFF is used for storing sound data for PCs. It can also stream multiple audio files

RIFF – Resource Interchange File Format. A generic file container format used for storing data in tagged chunks. RIFF is the same as WAV but it’s an older version, low quality audio.

AU – a simple audio file format presented by Sun Microsystems. It was used mostly on NeXT systems and early web pages.

SMP – SmartMusic Performance. Used in SmartMusic, it is a music practice application for a band, orchestra and voice.

Lossy Compression

MP3 – an audio coding format for digital audio which uses lossy data compression. MP3 file are most used for just audio just as a song or voice.

RA – a propriety audio format made by Real Networks. It was used for streaming audio by the BBC

Audio Sampling:

Resolution and bit-depth can constrain file size by the amount you use

E.g. if you look at the 2 pictures above you will see on the first one that the resolution is 72, the bit-depth is 8 and the image/file size is 452.2K. The second one is a blank A4 template, the resolution is 40, the bit depth is 32 and the image/file size is 1.77M. The further you lower the bit-depth and resolution the lower the file size will be.

Sample Rate – the number of samples of audio that are carried each second.

Mono – this means alone, so a song with a guitar solo is Mono

Stereo – Sound that is forced through 2 or more speakers so that it becomes surround sound.

Surround sound - Surround sound a realistic effect that makes you able to hear where sound is coming from. E.g. if you have headphones in playing a game and there’s an enemy to your right, you will be able to hear their footsteps through your right headphone.