HDTV standards:
The HDTV-Standard – usually abbreviated as HD – describes two formats that differ regarding the number of vertical pixels: 720 pixels or 1080 pixels.

720 pixel formats: 720 horizontal lines (i.e. 720 vertical pixels) with 1280 pixels per each line

• 720p/50 format: 720 horizontal lines with progressive scan and a frame rate of 50 frames per second

1080 pixel formats: 1080 horizontal lines (i.e. 1080 vertical pixely) with 1920 pixels per each line

• 1080i/25 format: 1080 horizontal lines with interlaced scan image capture (i = interlaced) and a frame rate of up to 25 frames per second
• 1080p/50 format: 1080 horizontal lines with a progressive scan image capture (p = progressive scan) and a frame rate of 50 frames per second.

Advantages of HDTV

• Up to five times higher resolution than SDTV (Standard Definition: PAL, NTSC, and SCAM)
• Thus significantly higher image quality than with SDTV
• Widescreen format with a 16:9 aspect ratio