EDTV

百科解釋

目錄·定義
·HDTV、 EDTV、SDTV
·示例
·EDTV vs HDTV

　　EDTV（Enhanced definition Television），即增強(qiáng)清晰度電視。
　　其水平掃描行數(shù)為500線-700線，主要是對應(yīng)現(xiàn)有電視分辨率量級，其圖像質(zhì)量為演播室水平。

HDTV、 EDTV、SDTV

　　　高畫質(zhì)數(shù)字電視(HDTV)與加強(qiáng)畫質(zhì)數(shù)字電視(EDTV)及標(biāo)準(zhǔn)畫質(zhì)數(shù)字電視(SDTV)有什么差別?
　　HDTV為英文High Definition Television的縮寫，意為高清晰度電視。高清晰度電視必須至少具備720線逐行(720p)或1080線隔行(1080i)掃描，屏幕縱橫比為16:9，音頻輸出為5.1聲道(杜比數(shù)字格式)，同時(shí)能兼容接收其它較低格式的信號并進(jìn)行數(shù)字化處理重放。
　　EDTV為英文Enhanced Definition Television的縮寫，意為增強(qiáng)高清晰度電視。要求電視至少具備480線逐行(480p)掃描，音頻輸出為杜比數(shù)字格式。
　　 SDTV為英文Standard Definition Television的縮寫，意為標(biāo)準(zhǔn)高清晰度電視。要求電視至少具備480線隔行(480i)掃描。該標(biāo)準(zhǔn)是高清電視標(biāo)準(zhǔn)的最低標(biāo)準(zhǔn)。
　　HDTV、EDTV與SDTV區(qū)分了數(shù)字電視機(jī)重現(xiàn)各種畫質(zhì)之?dāng)?shù)字電視廣播訊號的能力。電視臺可以用ATSC數(shù)字電視標(biāo)準(zhǔn)中18種畫面格式的任一種來播送數(shù)字電視節(jié)目，高畫質(zhì)數(shù)字電視機(jī)(High Definition Television，HDTV)能接收全部ATSC 18種數(shù)字電視畫面格式，并且用交錯(cuò)式1080條掃描線(1080i)或循序式720條掃描線(720p)的掃描方式重現(xiàn)高畫質(zhì)數(shù)字電視(HDTV)節(jié)目原來的品質(zhì)，不會將高畫質(zhì)的節(jié)目訊號降低品質(zhì)播出。加強(qiáng)畫質(zhì)數(shù)字電視機(jī)(Enhanced Definition Television，EDTV)能接收全部ATSC 18種數(shù)字電視畫面格式，并且用循序式480條掃描線(480p)的掃描方式播放顯示出節(jié)目畫面。標(biāo)準(zhǔn)畫質(zhì)數(shù)字電視機(jī)(Standard Definition Television，SDTV)能接收全部ATSC 18種數(shù)字電視畫面格式，而且用同于現(xiàn)有模擬電視的交錯(cuò)式480條掃描線(480i)的掃描方式來播出所有18種的畫面格式。這表示原本用高畫質(zhì)播送的數(shù)字電視節(jié)目品質(zhì)被大大降低以搭配電視機(jī)480條掃描線的品質(zhì)。

示例

EDTV vs HDTV

　　Confused by EDTV vs HDTV? We don&＃039;t blame you. The number of acronyms floating about with regard to digital TV is frightening. What&＃039;s even more worrying is that very often they are used by people who have little or no knowledge about what they mean. If the person selling you doesn&＃039;t know the difference between EDTV vs HDTV, how are customers supposed to decide which TV or projector to go for?
　　In our guide below, we&＃039;ve tried to distill the technical info into as few words as possible and make it as straightforward to understand as we can.
　　To properly explain EDTV vs HDTV, we need to step back a bit. Traditional TV has 525 lines of video which are interlaced. Interlacing just means that every frame of video is split into two fields and each field is shown alternately. Although there are 525 lines in the signal, only 480 lines contain video, so it is sometimes referred to as 480i (480 lines interlaced). This is known as Standard Definition TV, or SDTV. While this has worked well enough for fifty years, as TV sets have got bigger and projectors more popular, the quality deficiencies have become increasingly apparent.
　　The ultimate answer to improving the quality of the image displayed on your TV is HDTV, however, as a step on the road to HDTV, the industry came up with Enhanced Definition TV, or EDTV. This system contains the same 480 lines as SDTV, but they are progressive scan. Hence EDTV is also known as 480p. Progressive scanning just means that instead of splitting the signal into two fields and showing half the lines at a time, all 480 lines of video are shown at once. This results in a noticeable improvement in the quality of video.
　　The bad news in relation to EDTV vs HDTV is that you need a completely new TV or projector to display both EDTV and HDTV. Most DVD players on the market today are progressive scan, meaning they output EDTV signals, however, in order to view the progressive scan picture in all its glory, you need a TV or projector capable of displaying it and that, unfortunately, means getting a new TV.
　　In terms of content, there is very limited TV content available in HDTV format, and there is still wrangling about the standard for HD DVDs. However, every DVD disc on the market can be displayed in EDTV right now.
　　Bottom line? Pretty much every HDTV projector or TV on the market today will display EDTV as well. So even if you live in a country or area where HDTV content is limited or non-existent, it is worth it to watch your DVD collection in EDTV, the difference between SDTV and EDTV really is that big.
　　Kenny Hemphill is the editor and publisher of The HDTV Tuner - a guide to the kit, the technology and the programming on HDTV.

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