An audio file format is used for storing sounds (music, voices and more) in digital form. The industry has produced many formats for a primary or exclusive application or production, or preservation and dissemination. The program element that transforms the signal file is called a codec, short for coder-decoder. Users can also take advantage of a free online video converter.
Psychoacoustic audio encodings. They reduce the amount of information transmitted by limiting the description of the signal to the part that humans can perceive. All audio files limit the frequencies transmitted to the human ear.
For a smaller rate, codecs can take advantage of masking effects, frequency and time of human hearing, and the low spectral discrimination heights in the top two octaves of hearing. When reducing the amount of data, it may be necessary to define a permissible reproduction quality, which is distinct from the highest quality possible.
Some encodings work better with lengthy calculations, which take into account or in several passes, the entire audio segment and are thus unsuitable for applications in real time. At various points encodings thus compromise the cost of production, the bit rate and perceptual quality. Currently, the most used codec is by far the mp3, wma monitoring, and AAC.
Many files use the format (RIFF), which may contain a number of diverse elements (chunks). A header which occupies the first four bytes indicates the type RIFF, monitoring necessary information about the location of other elements, constructed recursively in the same way. These elements can contain any type of data.
Those that encode these elements indicate the sound codec in their header. The machine skips elements that it can not decode. Some systems and human users can use the extension of the file name data conventionally indicates the file format. However, this indication, mostly indicates a list of possible codes, not the encoding itself.
CDA (Compact Disc Audio) is a specific Microsoft Windows format, audio CD tracks as they appear when inserted into the CD-ROM drive. The sampling used for the CD technique is pulse coded (PCM for Pulse Coded Modulation). The file suffix .Cda is created.
Audio codec with lossless compression
The lossless audio compression like any other computer file identifies redundancies in audio files. With reference to the information theory of Claude Shannon, it is described as entropy coding. Lossless compression entails using an algorithm such that we can always recover the original data.
This file contains no useful information neither discernible frequency, level variation or rhythm, all the elements that make the difference between the signal and noise are based on repetition.