Updated April 10, 2017. In grammar, a demonstrative is a determiner or a pronoun that points to a particular noun or to the noun it replaces. There are four demonstratives in English: the near demonstratives this and these, and the far demonstratives that and those. This and that are singular; these and those are plural.
In the context of video compression, codec is a concatenation of encoder and decoderâa device that only compresses is typically called an encoder, and one that only decompresses is a decoder. The compressed data format usually conforms to a standard video compression specification.
1) In communications engineering, the term codec is used in reference to integrated circuits, or chip s that perform data conversion. In this context, the term is an acronym for  co der/ dec oder.. This type of codec combines analog-to-digital conversion and digital-to-analog conversion functions in a single chip.