"Dolby Vision" aims for a new HDR video experience.Will Ultra HD BD support soon? --Av Watch
On the other hand, the HDR technology used in Ultra HD Blu-ray is called "HDR10".HDR10 also uses PQ (ST2084), but it is stipulated for each title if the metadata is handled HDR10, and the Dolby Vision can be set for each scene.
In the current consumer display, the high -end models of LCD TVs are more than 1,000nit, and the brightness of 10,000 nits looks higher than necessary.In fact, the average screen brightness in movies is 25-40nit, which does not change even if it is HDR.However, there are many scenes that exceed 10,000 nits, such as one point reflection of one point with a screen.It is said that such differences in expressions such as small light sources can lead to the difference in overall image quality and texture, so it is not unnecessary specifications.
In HDR10, each title has static metadata such as "maximum brightness of 1,000 nits", and the brightness of each scene is determined by relative value.On the other hand, in Dolby Vision, you can have metadata such as brightness information for each scene, and if you control more detailed control, you can also have metadata for each frame, and use that data for LED backlight control.Say.Therefore, it is possible to increase the dynamic range more accurately and efficiently.
In addition, by using metadata, the brightness data can be efficiently down mapped, so if it is compatible content, it can be expected to improve image quality, such as a low -cost LCD TV of about 400nit, which approaches 1,000nit.It is also a feature of Dolby Vision.Furthermore, if the content is created assuming 4,000 nits, if the performance of the TV is improved to 1,500 nits and 2,000nit in the future, if you buy a TV, you can bring out the same content.It will be like that.
In Japan, Netflix launched HDR distribution in Marcopolo's Dolby Vision method (combined with HDR10).Hikari TV will also be compatible with Dolby Vision this summer, and Amazon videos will soon be available.
On the other hand, Ultra HD Blu-ray (UHD BD) requires HDR10 and Dolby Vision is optional.Dolby Vision -compatible UHD BD players and titles have not been released, but preparations are progressing.
In Dolby Vision, the basic information called a base layer (BL) and the additional information called the enhancement layer (EL) are also transmitted.If Dolby Vision is not supported, only BL is applied, output as a normal SDR, and in the case of Dolby Vision, BL+EL is transmitted, and output as Dolby Vision HDR.The capacity of EL is 25%or less of BL.
Dolby Visionのデコーダ/コンポーザー構成In the case of UHD BD, HDR10 is output based on 10 -bit HDR10 and Dolby Vision compatible devices.In the case of a compatible device, add an EL and metadata to the signal of the HDR10, equivalent to 12bit, and outputs Dolby Vision.However, in order to handle two HEVC data in BL and EL, it is necessary to respond to the video processing chip side.In order to decode two layers, 4K/60p UHD BD content requires two HEVC decoders, and there are issues on the player's side.However, if it is 4K/24P, one chip processing by time -division processing is possible, and the corresponding chip has already been completed.
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