What Is HD?
HD is short for High Definition Television commonly featuring 1080 horizontal TV lines. It is usually assumed that HD will be in the Widescreen 16:9 format and so therefore delivers 1125 by 1920 pixels per line (active pixels of 1080 vertical by 1920 horizontal pixels) that's about 2.2 million pixels and the closest digital format we have to 35mm film (which is not measured in pixels, but on the atomic level). Like 35mm, HD maintains its quality throughout the conversion process, whether it’s cross conversion to film or down conversion to PAL, NTSC, SECAM or DVD. With new media technologies ever-advancing, and the desire to cut down on cumbersome and costly 35mm film, HD comes as a versatile alternative for cinematographers to work with.
Four HDTV production systems are recognised for use in Europe:
- 1280 horizontal samples and 720 active lines in progressive scan with a frame rate of 50 Hz, 16:9 aspect ratio. Abbreviated 720p/50.
- 1920 horizontal samples and 1080 active lines in interlaced scan with a frame rate of 25 Hz, 16:9 aspect ratio. Abbreviated 1080i/25.
- 1920 horizontal samples and 1080 active lines in progressive scan and a frame rate of 25 Hz, 16:9 aspect ratio. Abbreviated 1080p/25.
- 1920 horizontal samples and 1080 active lines in progressive scan at a frame rate of 50 Hz, 16:9 aspect ratio. Abbreviated 1080p/50.