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  1. 1.  Describe the various audio formats used in digital media
  2. 2. In This Chapter, you’ll learn on:  The basics of Digital Audio formats  Identifying of the Various file types such as MP3, AIFF, WAV, AAC, WMA and etc  The characteristics and use of the various audio formats
  3. 3. Basics of digital audio formats  An audio file format is a file format for storing digital audio data on a computer system. This data can be stored uncompressed, or compressed to reduce the file size. It can be a raw bitstream, but it is usually a container format or an audio data format with defined storage layer.  Hundreds of file formats exist for recording and playing digital sound and music files and most of these file formats are software dependant. While different operating systems have different popular music file formats, we will focus on those that are well-known and widely supported file formats.
  4. 4. File Format and Codec  An audio file format and audio codec (compressor/decompressor) are two very different things. Audio codecs are the libraries that are executed in multimedia players. The audio codec is actually a computer program that compresses or decompresses digital audio data according to the audio file format specifications.  Most of the publicly documented audio file formats can be created with one of two or more encoders or codecs. For example, the WAV audio file format is usually coded in the OCM format, as are the popular Macintosh AIFF audio files.  Although most audio file formats support only one type of audio data (created with an audio coder), a multimedia container format (as Matroska MKV or AVI) may support multiple types of audio and video data.
  5. 5. Using the right compression  There are different kinds of compression for different jobs. There are audio codecs (like MP3) that allow you to quickly download music via the Internet and store lots of songs on your portable player.  Most audio digital formats allow you to select different degrees of compression when you're creating, or encoding, a file. For instance, MP3 files can be encoded at different rates of compression for varying file size and sound quality. File resolution is measured in kilobytes per second (kbps) — that is, how many thousands of bytes it takes to store one second of music. This figure is known as the bitrate.
  6. 6.  The higher the resolution, the more information from the original source is retained. A 256kbps file, for example, holds twice as much data as a 128kbps file. Generally, the smaller the bitrate, the more a file is compressed and the more it will be subject to a loss of quality.  However, smaller files are easier to store and quicker to download or transfer. When you're downloading files or encoding your own, consider how you'll be using them, and choose from your compression options accordingly.
  7. 7. The above chart shows the relative file sizes of the same three-minute song saved in different formats, starting with the original CD track on the left.
  8. 8. The following table lists the music file types that are supported in Windows (Without installing any additional software)
  9. 9. Below are audio file formats and codecs that QuickTime Player can playback in Mac OS. (Without installing any additional software)