Short answers, pulled from the story.
High-definition video is video with considerably more than 480 vertical scan lines in North America or 576 lines in Europe. HDTV resolution is 1,080 or 720 lines, compared to 480 lines for NTSC-based standard digital television. There is no single internationally standardized definition of high-definition.
Japanese engineers at NHK developed the HighVision 1,125-line interlaced HDTV standard, also called MUSE, running at 60 frames per second. Sony's HDVS system based on this work was presented at an international meeting of television engineers in Algiers in April 1981. NHK then presented the full analog HDTV system at a conference in Switzerland in 1983.
Discrete cosine transform compression, first proposed by Nasir Ahmed in 1972, achieved a data compression ratio of around 100:1 compared to uncompressed video. Uncompressed 1080p video exceeded 1 bit per second in bandwidth, making it impractical without compression. Motion-compensated DCT was adopted in H.26x formats from 1988 and MPEG formats from 1993, and became the accepted HDTV coding standard by the early 1990s.
The FCC officially adopted the ATSC transmission standard in 1996, covering both HD and standard-definition video standards. The process began in 1987 at the request of American broadcasters. The standard included interlaced 1,080-line video at a maximum of 30 Hz and progressive 720-line video at a maximum of 60 Hz.
Toshiba announced on the 19th of February 2008 that it was abandoning the HD DVD format and would discontinue development, marketing, and manufacturing of HD DVD players and drives. Blu-ray Disc, developed by nine initial partners including Sony, Philips, and Pioneer, won the format war. Blu-ray holds 25 gigabytes on a single-layer disc and 50 gigabytes on a double-layer disc.
Progressive scanning, marked with a p, redraws every line of the image with each refresh cycle, while interlaced scanning, marked with an i, draws odd-numbered lines first and even-numbered lines on a second pass. Interlaced scanning yields full resolution when subjects are still but can lose up to half its resolution and produce combing artifacts when subjects are moving. The 720p format is generally more accurate for fast-action content because every frame is complete.