一般顯示器模擬觀看HDR效果
4K電視技術，進展到目前的階段已經越來越成熟完美，正在進行的HDR(High-Dynamic Range)技術，也就是高動態範圍，類似我們用相機多張不同曝光的照片疊加處理成一張明暗層次都都分明的影像，避免出現過亮或過暗的情況。下圖就是一個 HDR 照片範例。
左邊為原始照片，右邊為開啟 HDR 功能。
目前看到流出的HDR影片，總是灰灰無色彩，透過MediaInfo 最新版本，即可分析出影片結構。
MediaInfo 最新版本，可以識別 HEVC 的 HDR 資訊，包含 CEA 861.3 MaxCLL (最高內容亮度) 、 MaxFALL (平均格最高亮度)以及 SMPTE ST 2084
LAV Filters 0.67 + madVR 0.90.3 可以正確識別 ST 2084 資訊，達到一般螢幕模擬 HDR 效果。
現在外接含有HDR功能的顯示器會不會正常啟動 HDR?還有看播放器有沒有正確傳送 Metadata 給播放裝置，另外 ST2084 的 PQ Curve 雖然與 Dolby Vision 一樣，但是 Dolby 有再多包了一些 Metadata 進去，所以嚴格說起來兩者是不相同的，Dolby Vision 還是要給 Dolby 包裝。接下來就等4K Ultra HD Blu-ray的到來，才能實際做驗證了。
資料來源及圖文教學
本文章最後由 pp300 於 2016-3-10 09:22 編輯
目前電腦螢幕中並沒有像電視一樣 HDR 的解譯晶片及電路
不過透過最新的 LAV Filter 0.67 Beta 搭配 madVR 0.89.18 以上版本，已經可以順利的透過螢幕模擬出 HDR 的效果，並於 madVR 可以看到相關資訊顯示
目前製作 HDR 的問題是太多複雜的規格、製作技術的軟體的封閉，以及相關資訊嚴重缺乏即不透明
未來誰能一統江山，還要等再競爭才能得出結果
這個模擬工具，簡單說就是把 ST.2084 的訊源對應到 REC.709 上頭！
有點像是在拍 S-Log 時套 709 的 LUT 一樣
HDR 比較麻煩的就是不僅顯示端要支援，倒推播放端、製作端、拍攝端都要符合規範。但現在規範各家又還在「喬」... 真不知什麼時候才能「喬好」啊～ 本文章最後由 6hzzz 於 2016-3-7 14:49 編輯
madVR真乃神器也，PC的福音。
madVR HDR 設置爲120
madVR HDR 設置爲180
madVR HDR 設置爲265
madVR HDR 設置爲400
madVR HDR 設置爲600
問題來了，究竟哪個參數才正確呢？是否要匹配電視機的參數呢？
把顯示器亮度調到最高，效果更明顯。 本文章最後由 6hzzz 於 2016-3-7 14:51 編輯
轉貼：
The big keyword for this build is HDR. I suppose many users might not know how it works exactly, so some explanations:
1) First of all, this madVR build does *not* aim to send HDR content untouched to the display, to let a "HDR compatible" display do all the processing. Doing that might be supported by some future version (as an option). But for now what madVR does is convert the HDR content in such a way that it looks well on *any* display (new and old), regardless of whether the display officially supports HDR or not.
2) The key idea of HDR is to increase the peak white luminance, so that we can get brighter highlights, and more texture detail in bright image areas. HDR content uses 10bit (or more) instead of the usual 8bit, and it also uses an improved transfer (gamma) function, which means we also get better shadow detail at the same time.
3) HDR content is encoded using a totally different transfer ("gamma") curve. So playing HDR content with a media player and display which don't understand the new transfer function won't look good/correct. It will look totally washed out.
4) The new transfer function directly maps each pixel to a specific desired luminance value (in "nits" or cd/m²). Possible values are 0 nits up to 10,000 nits. However, videos don't have to use the full 0 - 10,000 range, they often top out at either 4,000 nits or 1,200 nits (from what I've seen).
5) UHD Blu-Ray will usually be encoded in BT.2020 color space, which is extremely wide. However, videos don't have to use the full BT.2020 space, they usually only use DCI-P3, inside of the encoded BT.2020 container.
6) Today's displays (even the best of the best) cannot really properly reproduce HDR content. E.g. many display's don't reach full DCI-P3 colors yet (let alone BT.2020), and no available display today comes even close to be able to output 10,000 nits! Which means that someone somewhere has to convert the HDR content down to something the display can handle. The consumer electronics world plans that the display will do this conversion (only new models, obviously) - and every TV manufacturer will write their own conversion algorithms because there's no standard for that! From what I've been told those conversion algorithms (at least for the first few HDR display generations) are probably not going to be very high quality.
7) madVR is able to compress both the luminance and the colors down to what your display can handle. It uses reasonably high quality algorithms for that. I might find even better algorithms in the future, but for now these algorithms should be a good starting point.
8) UHD Blu-Rays will come with an updated copy protection. So madVR will not be able to play them - unless the copy protection gets broken at some point.
If you want to test HDR playback, please update to a new LAV nightly build because only the latest LAV nightlies are able to pass some HDR metadata information to madVR!
下載：
http://madshi.net/madTestPatternSource.zip
下載LAV nightly build：
http://files.1f0.de/lavf/nightly/
6hzzz 發表於 2016-3-7 10:28 static/image/common/back.gif
madVR真乃神器也，PC的福音。
madVR HDR 設置爲120
其實應該沒有所謂的標準，畢竟只是模擬的，只要找到是最適合硬體顯示的參數
我的螢幕是使用 ASUS PA246Q，官方資料室寫料度最高可以達到 400 cd/m^2
所以我 madVR 就是把亮度設在 400 nits，之後把螢幕標準模式的亮度拉到最亮，口味重一點的話再加點對比度，把環境光調低，模擬出來的感覺還蠻強烈的
如果電視有動態對比 Local Dimming 的話，也可以開啟來加強效果
模擬畢竟是模擬，只有爽度問題，準確是另外回事 madVR真係好勁，模擬到HDR廣色域，啲片色水即刻靚左好多。
而且又有NNEDI3既升綫技術，舊片480p拉上1080p都睇得入眼。
所以小弟寫左篇madVR教學，希望大家容易啲入門
http://ppkkkp.blogspot.com/2016/07/madvr.html
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