The different types of digital processing include image processing, audio processing, video processing, signal processing, and data processing. In the most basic terms, this process refers to any manipulation of electronic data to produce a specific effect.
Image processing is perhaps the best known example of digital processing. Used in the web graphics and photography industries, this form of digital processing allows the user to manipulate the data in the image to add watermarks, adjust the coloration, apply dithering, or perform other tasks to alter or enhance the image. Image processing is closely tied to video processing, which carries the process further, enabling the user to edit and manipulate full video files. By incorporating multiplexing during video processing, the user can add metadata, such as subtitles or closed captioning, that can be retrieved on demand and hidden when not in use.
Multiplexing is also used for signal processing. Digital television and telephone services rely on the use of multiplexing. In television, multiple channels on a single line can be provided using this technique. The telephone service industry also relies heavily on digital processing to be able to serve multiple customers on a small number of lines.
Audio processing is another form of digital processing that allows the user to clean-up or mix sound files. Using various processing techniques, the sound engineer can add tracks to a file, remove background noise, or otherwise enhance the audio files. It is even possible to add a digital watermark to sound files for purposes of copyright protection. In some cases, sound engineers also add noise to an audio track in a process called dithering, which serves to enhance the overall quality of the sound file by smoothing some of the harsh changes in the audio as sounds move up and down on the frequency waveform. This same technique is also used in image and video processing to smooth the finished digital images.
Digital processing is also used to manipulate or study data. In some cases, this data processing is used for public safety, as in the case studies of earthquake or hurricane activity. Digital data processing provides a much faster and accurate means of data processing, enabling increased warning times for impending disasters. It is also used in laboratory research of medicines and computer sciences to quickly work through the complex computations that once required hours of intensive research and manual processing.