Uncompressed Formats
WAV (or WAVE)
This is a Microsoft and IBM Audio File format standard for storing audios on PCs. It happens to be the native digital audio format in Windows. In WAV files, 8-bit or 16-bit samples are taken at rates of 11 kHz, 22 kHz or 44.1 kHz. The highest quality (16-bit at 44,1 kHz) uses 88KB of storage per second of music. The WAV format is widely used as the medium for professional recording and editing. For creating audio CDs, WAV files are converted to the CDDA audio format. Both CDDA files and WAV files at their highest sampling rates take up a similar amount of storage space, an are not compressed (like mp3 is). But WAV is not the same as CDDA, as some people believe.
AIFF
Audio Interchange File Format is another format used for storing Audio data. It supports a variety of bit resolutions, sample rates and audio channels. This format is very popular on Apple platforms, and is widely used in professional programs that process digital Audio waveforms. The format was co-developed by Apple Computer based on Electronic Arts' Interchange File format (IFF). There is also the AIFF-Compressed AIFF-C or AIFC) format which supports compression ratios as high as 6:1.
AIFF is one of the two most-used Audio file formats on Mac Operating Systems. The other is Sound Designer II (SDII)
The extension for AIFF is .aif when used on a PC.
AU
The .au format, originally by Sun, isn't widely supported outside the UNIX community. “AU” is short of “Audio”. It is the standard Audio file format for the Java programming Language.
COMPRESSED LOSSLESS FORMATS
Lossless compression is a compression technique in which data can be decompressed back to its original form without any loss. The decompressed file and the original file are identical. For example, ZIP is used to compress the Documents, etc.; there are similar compression techniques used for Audio and Video. Apple Lossless, WMA Lossless and FLAC are examples of lossless compression applied to CD Audio. These methods can reduce a full Audio CD only to about half of its original size.
A word about containers is in order here. A container format is a file format that can contain various types of data, compressed in a manner of standardized codecs. The container file is used to be able to identify and interleave the different data types.. Simpler container formats can contain different types of Audio codecs while more advanced container formats can support Audio, Video, subtitles, chapters and metadata, along with the synchronization information needed to play back the various streams together.
Apple Lossless
Also known as Apple Lossless Encoder. ALE, or Apple Lossless Audio Codec (ALAC) this is an audio codec developed by Apple for Lossless compression of digital Music. Apple Lossless data is stored within a MP4 container with the filename extension .m4a. Apple claims that Audio files compressed with its Lossless codec will use up “about half the storage space” that the uncompressed data would require. Testers have found that compressed files are about 60 percent the size of the originals, similar to other Lossless formats. Compared to most other formats, Apple Lossless is not as difficult to decode, making it practical for a limited-power device such as an I-Pod.
FLAC
An acronym for Free Lossless Audio Codec, this I a popular format for Audio compression. It is suitable both for everyday playback and for archiving Audio collections. It was developed by the Xiph.Org Foundation ( www.xiph.org ), and is royalty-free.
WMA Lossless
Windows Media Audio actually is the name of Microsoft's Solution for Digital Audio. WMA codecs once were only lossy, but with the release of Windows Media Encoder 9 series in early 2003, Microsoft provides the option of Lossless compression by Windows Media Audio 9 Lossless Codecs. WMA Lossless is, formally, a digital Audio file format that compresses an Audio CD to a range of 206 to 411 MB, at bitrates of 470 to 940 kbps. It uses the same .WMA file extension as other Windows Media Audio formats. |
