Videotape came in a variety of formats and sizes. Some were reel-to-reel and some were videocassettes. Videotape has been replaced by digital media. Video editing in real-time occurs when a multicamera program is produced with the use of a video switcher. New digital technologies have replaced videotape as the recording medium of choice. Two videotape machines were used: the playback or source Videocassette Recorder (VCR), which contained the original videotape, and the record or editing VCR, which contained a blank videotape. With the advent of digital technologies, methods of video recording have changed. For most of the last half of the twentieth century, video recording was dominated by the process of magnetic recording onto videotape. Digital recording media include flash memory cards and devices, computer hard disk drives and video servers, and optical media like DVDs and Blu-Ray discs.