- C, C++, C# — programming languages.
- C-Cube — C-Cube Microsystems is the leading global provider of digital video silicon and digital broadcast systems. This technology is used worldwide to enable digital video communications and consumer applications.
- CAVLC, CABAC — Context-Adaptive Variable Length Coding and Context-Adaptive Binary Arithmetic Coding are tools for entropy coding of the bitstream syntax (macroblock type, motion vectors + reference-index, etc.). CAVLC is a default compression method in AVC/H.264. CABAC is a more powerful compression method, which is able to bring down the bitrate additionally by about 10-15% (especially on high bitrates). Both these methods provide lossless compression and therefore never harm the quality, however using CABAC method slows down both encoding and decoding processes.
- Closed Captions — Textual video overlays that are not normally visible, as opposed to open captions, which are a permanent part of the picture. Captions are usually a textual representation of the spoken audio. In the United States, the official NTSC Closed Caption standard requires that all TVs larger than 13 inches include circuitry to decode and display caption information stored on line 21 of the video signal. DVD-Video can provide closed caption data, but the subpicture format is preferred for its versatility.
- Codec — coder/decoder or compression/decompression software or hardware module. Codecs are used to encode and decode (or compress and decompress) various types of data that would otherwise use up huge amount of disk space, such as raw sound and video files. Codecs can be used with either streaming (live media data) or files-based (AVI, WAV, MP4 etc) content.
- COM — The Component Object Model is an object-oriented programming model used by numerous applications.
- Communicator — personal Internet communicator - The PIC is a connecting device; a simple and accessible platform designed to work with existing service provider dial-up or broadband infrastructure that can deliver basic Internet functions such as e-mail, downloads, Web browsing, and more.
- CSS — Content Scrambling System is the data scrambling method used to garble the content of a DVD disc. According to most sources, CSS was put into use for the purpose of ensuring that copyrighted material placed in this format would only be usable with licensed DVD playback mechanisms. In some countries de-CSS playback support is illegal.