HDTV (high definition television) is a digital television standard that provides wide-screen picture along with CD quality audio. There are various HDTV standards:

• HDTV 1080p (1080 lines of progressive scanning, 16:9 aspect ratio)
  
• HDTV 720p (720 lines of progressive scanning, 16:9 aspect ratio)
• HDTV 1080i (1080 lines of interlaced scanning, 16:9 aspect ratio)

Most HDTV formats uses MPEG2 or H.264 as the video compression standard, while the latter has been adopted more widely because of its high compression efficiency.

Just like analog TV, HDTV can be delivered in various ways, including:

• Over-the-air broadcasts
• Broadcast satellite
• Cable HDTV
• High-definition disc - HD DVD and Blu-ray media

To watch HDTV, you need an high-resolution display monitor and an HDTV tuner either in one package or seprately. The tuner can usually receive both digital and analog over-the-air broadcasts. HDTV monitor can have either the squarish 4:3 aspect ratio or the widescreen 16:9 ratio.