06-12-2012, 04:01 PM
Audio File Formats
PPT on Audio file formats.pptx (Size: 499.64 KB / Downloads: 27)
Audio and Audio File Formats
Audio is an electrical or other representation of sound.
An audio file format is a file format for storing digital audio data on a computer system.
It can be a raw bitstream, but it is usually a container format or an audio data format with defined storage layer.
Audio Format/Codec
It is important to distinguish between a file format and an audio codec.
A codec performs the encoding and decoding of the raw audio data while the data itself is stored in a file with a specific audio file format.
In other words, Codec contains both an ADC and DAC running off the same clock.
Categories of Audio Files
There are 3 categories in which certain Audio files belong to:-
Uncompressed: Audio files that are not compressed and are capable of having a large file size. Ex) .Wav
Lossless: Audio files that are compressed but doesn’t lose any quality to the file. Ex) .WMA
Lossy: Audio files that lose some quality when being compressed. Ex) .Mp3
Uncompressed Audio Formats
There is one major uncompressed audio format, PCM, which is usually stored in a .wav file on Windows or in a .aiff file on Mac OS.
Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals.
BWF (Broadcast Wave Format) is a standard audio format created by the E.B.U.as a successor to WAV.
BWF allows metadata to be stored in the file
Lossless Audio Formats
A lossless compressed format stores data in less space by eliminating unnecessary data.
Uncompressed audio formats encode both sound and silence with the same number of bits per unit of time.
In a lossless compressed format, the music would occupy a smaller portion of the file and the silence would take up almost no space at all.