A Codec is the software or hardware that encodes and decodes a stream of digital data, especially audio and video.

The name codec comes from the combination of the words encoder and decoder. It's a "two-pronged" system: Encoding (Encoder): Takes a large audio or video file and compresses or formats it to a smaller size, making it easier to store or stream. Decoding (Decoder): Takes the compressed file and decompresses it so it can be played. Think of it as vacuum-packing an item to save space (encoding) and then opening the package to return it to its normal size (decoding). There are codecs Analog (such as Dolby A/B noise reduction systems for tapes) and digital. In the digital world, codecs are essential for everything from listening to an MP3 or FLAC to watching a video on YouTube or Netflix.