Lossless and Lossy Audio Codecs

Digital audio file formats  fall into two categories, lossless and lossy. Lossless codec makes use of the simple bit operations for reducing the number of bits needed to store one sample and therefore lead to reduce the size of the whole audio file. Lossy Codecs does not decompress audio files to their original data amount. Lossless methods can provide high degrees of digital compression, but there is no loss in size or sound quality. Lossless codecs provide the highest audio fidelity, but the files they create are relatively large file size.

Lossless codecs Lossy codecs
 * Windows Media Lossless
 * Apple Lossless
 * Free Lossless Audio Codec (FLAC)
 * MP3 or MPEG-1 Audio Layer 3
 * Windows Media Audio WMA
 * Advanced Audio Codec AAC
 * Ogg Vorbis

Advanced Audio Coding  Advanced Audio Coding standard issued in 1997 and has three profiles, of which the Low Complexity  Profile was most widely deployed. Advanced Audio Coding (AAC) is a multi-channel perceptual audio coder that provides excellent compression of music signals while achieving transparent quality relative to a stereo Compact Disc original for audio material when coded at 128 kb/s. AAC technology can be used for coding audio files at medium to high bit rates.

The development of AAC began when researchers became convinced that significant improvements would be possible by abandoning backward compatibility to the earlier MPEG layers. AAC has now been formally embedded in both the MPEG-2 and MPEG-4 audio standards

High-Efficiency Audio Coding  The MPEG High Efficiency Advanced Audio Coding technology is a lossy compression system for digital audio and it was standardized in 2003, as amendment 1 to MPEG-4 (ISO/IEC 14496-3:2001/Amd 1:2003 Bandwidth extension). High-Efficiency Audio Coding has proven in several independent tests to be the most efficient audio compression scheme available worldwide.

There are two versions of this compression scheme: HE-AAC and HE-AAC v2. This coding enhancement technology, which is particularly good for streaming voice transmissions. HE-AAC v2 presented new audio enhancements like downmixing stereo to mono and spline resampling.

Audio codec formats 1- WAV, or Waveform Audio Format, is an uncompressed audio format that's great to use if you want to get the original recorded material without losing sound quality. It is commonly used for storing uncompressed (PCM). 2- Windows Media Audio is the standard audio format created by Microsoft and used by Windows Media Player and compatible hardware. 3- FLAC is an open-source lossless compression codec that delivers CD-quality audio in a file size smaller than an actual CD. 4- AAC is Apples offering to the audio format world and the file type you would expect when downloading from the apples store. AAC files are usually ADTS or ADIF containers. 5- Ogg Vorbis is an open-source and patent-free audio codec that's great for streaming over the internet without compromising speed. Vorbis offers compression similar to MP3 but is less popular. 6- AIFF is a standard uncompressed CD-quality, that's completely uncompressed and can be played on both Macs and PCs. 7- DSD was developed even before the year 2000 by Sony and Philips as the format for the Super Audio CD. It is even higher in quality than CD-quality and HD download formats such as FLAC and ALAC.