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發表於 2005-8-27 07:14:53
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<br><br><br><br><br><br><table cellpadding=0 cellspacing=0 border=0 WIDTH=94% bgcolor=#000000 align=center><tr><td><table width=100% cellpadding=5 cellspacing=1 border=0><tr><td BGCOLOR=#F8F8F8><font id=quote><b>下面引用由<u><a href="pop_profile.asp?mode=display&id=31" target=_blank>LibraC</a></u>在 2005/08/26 03:10:44 AM 發表的內容:</b>
越來越佩服Peter大哥了!
我到現在還沒到完全看懂大哥的分析!
很笨的問一下, 60Hz 跟 48Hz對流暢度影響?
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我修改一下,
我用一般的普通話語解釋,
原來的電影是24 frame,
當你要用每秒60 interlace field 來傳送或是表現時,
就要用到所謂的3:2 pull down,
利用運算製造出60張interlace 畫面,
之後又要轉化為原來的24張.所以會有不順的感覺.
(因為24張要如何均勻的分成60張之間?)
24 frame 要表現成48frame, 相對就簡單了,
只要改成多插一張就OK了.
24fps 的 film 在60Hz的TV表現如下,
如果高級DVD player 正確的解時,他也可以把 interlace 的多的 aaabbccc拿掉一個,變成
aabbcc組成progress scan A-B-C,(A 表整個圖, a 表interlace 半個圖)但是當它要秀60Hz時,又會有AAA-BB-CCC的呈現,所以我們會看到A*3 呈現1/20, B*2呈現 1/30sec,
重點是每張圖給我們的速度感會是每1/20秒與1/30秒show 一張圖,交替的時快時慢.Judder 由此而生.
http://www.hometheaterhifi.com/v ... essive-10-2000.html
This form of display gives us a moving image very close to the original film. It has a tendency to "judder" a bit though, as the frames alternate between being shown for 1/20th of a second and 1/30th of a second. Even our little synthesis of the final product, which actually contains 10 pieces, shows this judder. In the future, both the player and the display could increase their display rate above 60 fields per second, to 72 per second. At that point, the fields would only last 1/72 of a second, permitting the player to show every film frame three times (24 x 3 = 72), eliminating the motion judder. 72 fps will only work with film based sources though, as it is a multiple of 24. It will not work well with video sources which are 60 field per second. What we need are TVs which, like our computer monitors, can operate at a variety of frequencies, adapting to different sources, but that’s a subject for another day.
<font color="#000066">[這篇文章最後由Jeff Hsu在 2005/08/27 03:36:30 AM 編輯]</font> |
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