1080i is a shorthand name for a category of video modes. The number 1080 stands for 1080 lines of vertical resolution, while the letter i stands for interlaced or non-progressive scan. 1080i is a high-definition television (HDTV) video mode. The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels and a frame resolution of 1920 × 1080 or about 2.07 million pixels. The frame rate in hertz can be either implied by the context or specified after the letter i. The two frame rates in common use are 25 frame/s (in countries that use 50 Hz alternating current) and 30 frame/s (in 60 Hz countries), with the former (1080i25) generally being used in traditional PAL and SECAM countries (Europe, Australia, much of Asia, Africa), and the latter (1080i30) being used in traditional NTSC countries (e.g. United States, Canada and Japan). Both variants can be transmitted by both major digital television formats, ATSC and DVB. The European Broadcasting Union (EBU), prefers to use the resolution and field rate separated by a slash, as in 1080i/30 and 1080i/25, likewise 480i/30 and 576i/25.
Due to revision of the NTSC format when color became available, the frame rate of actual 1080i broadcasts is usually 0.1% slower than is implied. For example, a 1080i30 or "30 Hz" transmission actually displays about 29.97 frames each second. Both the straight 24/30/60 and 23.976/29.97/59.94 frequencies are supported by current standards.
For a comparison between 1080i and 720p, see the 720p article.
See alsoTelevision Portal
- High Definition (HD) Image Formats for Television Production (EBU technical publication)
- 720p vs. 1080p HDTV: The final word - CNET Review - December 5, 2007
v • d • eDigital Video ResolutionsDesignation Usage Examples
Definition (lines) Rate (Hz) Interlaced (fields) Progressive (frames)