Audio - file formats

Question 1

WAV

Answer 1

A standard audio file format on PCs. A raw audio file that converts analog signals to binary data. Uses containers to store audio data, track numbers, sample rate, and bit rate. Uncompressed lossless audio file format, resulting in large file size and requiring much storage space.
o 4 min WAV roughly = 40MB

Question 2

WAV benefits

Answer 2

Lossless: accurately reproduces recording without losing audio quality.
o Simple format means that files are easy to process and edit. Editing software is readily available for this file format.
o Professional format used in professional settings (studio recordings, mastering and pro- audio applications).
o Highly compatible - widely supported by audio editors.

Question 3

WAV limitations

Answer 3

Large file size, very large, impractical for mobile devices and streaming, limited to files under 4GB

Question 4

AIFF (Audio Interchange File Format)

Answer 4

An audio file format standard used for storing sound data for personal computers and other electronic audio devices, originally developed by Apple Inc. Supports uncompressed PCM data.

Question 5

AIFF (Audio Interchange File Format) benefits

Answer 5

outputs excellent sound quality, saves original audio in uncompressed format.
o Allows users to store Metadata Stores track information - index data.

Question 6

AIFF (Audio Interchange File Format) limitations

Answer 6

Uncommon file format

with extremely large file size

Question 7

MP3

Answer 7

a shortened name for MPEG-2 audio layer III. MP3 is a lossy format, which means that encoding audio in MP3 will result in reduced quality alongside reduced size. It is rooted in theories of psychoacoustics (how people perceive sound) and used these to mask quieter sounds if there are sounds that are loud and stand out, removing ‘hidden sound’.
o Resulted in an explosion of audio sharing sites.
o 4minMP3roughly=4MB

Question 8

MP3 benefits

Answer 8

Small file format can be easily distributed over the Internet (small file size is easily transferred over platforms and devices).
Has become consumer standard for purchasing music.
o Files are compressed with little differences to the original sound quality.
o Editing software is readily available. Highly compatible.
o MP3 files are indexed (already has the name of the song and artist on the file). Data is attached to the file.

Question 9

MP3 limitations

Answer 9

Little disadvantage,

however sound quality is inferior to lossless formats like wav.

Question 10

WMA

Answer 10

A lossy audio codec based on theories of psychoacoustics. Audio signals that are perceived to be incomprehensible to human hearing are encoded with reduced resolution during compression.
o A file extension that stands for Windows Media Audio. Few programs support it in comparison to MP3. Microsoft created WMA in order to avoid the licensing issues associated with MP3.

Question 11

WMA benefits

Answer 11

Digital Rights Management
o Maintains a higher level of quality at
a lower bitrate
o Is not limited by licensing issues
that are associated with MP3 file
format.
o Audio signals that are perceived to
be incomprehensible to human hearing are encoded with reduced resolution during compression, meaning that background noises are reduced in volume, making the louder sounds stand out and increasing audio clarity and cleanness. Sound is removed, but it is sound that humans can’t detect.

Question 12

WMA limitations

Answer 12

inferior sound quality to

other lossy formats like mp3.

Question 13

MIDI

Answer 13

Musical Instrument Digital Interface file. It connects to musical instruments. MIDI doesn’t contain actual audio, resulting in small file size. This is because they contain the computerised equivalent of sheet music, meaning that they contain the instructions on how to play a tune (the notes, pitch and volume), and which computer generated instrument could play it, eliminating factors that could influence an audio recording.
o EG: DJ’s

Question 14

MIDI benefits

Answer 14

instructions
o Very small file size allows for easy
storage and transfer over platforms
and internet.
o Allows musicians and audio file
developers exchange music and data independent of the computer system or platform.
o Allows for exact editing of the audio file.

Question 15

MIDI limitations

Answer 15

Cannot record human
voice and needs to be converted into another format to be played through most devices. Otherwise, midis need to be played through a MIDI player.

Question 16

purposes of different file formats

Answer 16

To account for the resolution on different devices
o some file formats are easier to transfer from devices than others
o to enhance usability for the user as well as application programmers
o used to store different types of data (audio, graphic)
o PDF files have more security
o JPEG images keep their quality and are the most common type of image file used for
sharing images on the internet