Information About1080i |
| CATEGORIES ABOUT 1080I | |
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Some people prefer to use the line number of fields, which is half that of frames, in their nomenclature and thus call this mode 540i, likewise 240i and 288i . Others, including the European Broadcasting Union (EBU), prefer to use the frame rate instead of the field rate and separate it with a solidus from the resolution as in '''1080i/30''' and '''1080i/25''', likewise 480i/30 and 576i/25. 1080i is directly compatible with numerous CRT -based HDTV sets. 1080i is compatible with newer 720p - and 1080p -based televisions but must be Deinterlaced first in order to be displayed on those sets. Due to a curiosity of the NTSC format, the field rate of actual 1080i broadcasts is usually 0.1% slower than is implied. For example, a 1080i60 or "60 Hz" transmission actually displays about 59.94 fields 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.'' 1080I VS 1080P The progressive-scan versions of the 1080-line resolution is known as ). On the other hand, most consumer televisions in the world are currently not equipped to receive or decode a 1080p signal at any frequency. Moreover, displaying a p24 broadcast on an i50 system (such as PAL) requires the speed of video and audio be increased by over 4% (to 25 frames per second). Therefore a hybrid is often used for movies and the like: the frames (25 or 30 per second) are segmented into two interlaced fields with equal time index (''psf'', ''progressive in'' or ''with segmented frames''). The deinterlacer has to perform a simple ''weave'' only. This ensures compatibility with 1080i50/60 with only little less coding efficiency than 1080p25/30 and half the bandwidth requirement of 1080p50/60, but the SDTV problems of PAL Speed-up and Telecine Judder remain. It would be inefficient to transmit any signal with a frame rate significantly higher than its source’s, which is 24 Hz for movies. EXTERNAL LINKS |
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