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Audio files are sound files, or files that play a sound when clicked on. One of the most common audio formats is the wave file, or [filenamehere].wav. Another is the MP3 file, or [filenamehere].mp3. The type of audio format used is indicated by the file extension – the last three letters following the dot. Standard audio players included with operating systems will play common types of audio files, but more exotic sound formats might require downloading codecs for the player to extend its capabilities.
The ubiquitous wave format was developed by Microsoft® and IBM®, with Apple® offering up a compatible standard known as the Audio Interchange File Format (AIFF). Both types of audio files will play on IBM and Macintosh computers. WAV and AIFF are two types of lossless audio formats, or audio files that store the original audio bitstream source without any loss of quality. These formats were originally used for operating system sounds, such as beeps, chimes and spoken messages. As people began customizing their systems, short sound clips from movies and television or favorite song snippets became widely available online as wave audio files.
A potential drawback of the lossless format is its large footprint due to its high quality. When people began copying music CDs to computer, they quickly learned that ripping to WAV could consume as much as 5BM per minute. A four-minute song might result in a 20MB wave file. Online multimedia content presented another problem, as a lossless audio stream was too bulky to easily download, especially over the standard connection of the day, which at the time was dial-up. Development of compressed audio files or lossy formats like MP3 answered the call.
A compressed sound file sacrifices some loss in quality (hence the term “lossy”) as a tradeoff for a smaller footprint or file size. MP3 audio files are a perfect example. A 20MB wave file can be converted to MP3 format, resulting in a file that’s just a few megabytes in size. Other lossy formats include Ogg Vorbis (.ogg), Advanced Audio Coding (.acc) or MP4 (.mp4), and Windows® Media Audio (.wma). ACC/MP4 files are slightly smaller in size than MP3s with an encoding scheme that purportedly results in higher quality sound than MP3s. However, many sources claim OGG generates the best lossy audio files, smaller than MP4s with equal or better sound quality.
Going from wave to a lossy format the loss of quality should be minimal though audiophiles will be able to discern the difference. For this reason, many music lovers choose to archive music in lossless formats like WAV or AIFF, then generate lossy files as needed from the originals. Lossy audio files are fine for use with portable players where storage is limited and quality isn’t as critical. Untrained ears likely won’t hear the difference between an original wave file and its slimmed down lossy counterpart, but keep those lossless originals for burning CDs or playing through the home entertainment center.
Other types of audio files are embedded in “container” formats used for movie files that include sound. Apple’s QuickTime®, RealNetwork’s RealMedia®, and Microsoft’s Audio Video Interleave® (AVI) are a few examples.