“Not one sound”: How Dolby Vision makes the world brighter

    We recently talked about Dolby Atmos technology (we discussed it in more detail in our podcast ), which brings new audio sensations when watching movies. In this regard, it is worth mentioning one more technology, which is the second component of Dolby Cinema - Dolby Vision.

    Dolby Vision OgreBot / CC photography is a standard for high dynamic range (HDR) video. The essence of HDR video is not in high resolution; Realism is more accurate color and contrast than standard dynamic range (SDR). That is, the image becomes brighter, but only in the right places.

    About how this technology differs from HDR-photos can be read here . But if in brief - to get a wide dynamic range in the photo you need a few shots taken with different settings. In the situation with video, the emphasis is on a more detailed display of images at the same time in bright and dark places.

    What else is from HDR video

    There are other standards developed by different companies. In general, they can be divided into two main subgroups: PQ (Perceptual Quantizer) and HLG (Hybrid Log Gamma) - the latter is developed jointly by the British BBC and the Japanese broadcaster NHK. Technology Dolby Vision, as well as standards Prime Single (from Technicolor and Philips) and HDR10 belong to the first group - PQ.

    HDR10 and Dolby Vision support the technology of the electron-optical transfer function (EOTF), which was developed by Dolby. The Society of Film and Television Engineers (SMPTE) has standardized PQ technology called ST.2084.

    HLG technology is used for television broadcasting, as it can combine SDR and HDR into one channel, and the desired signal will be used depending on which receiver is the end user. You can read more about HLG technology here , but we already wrote about other types of HDR and how to use them in our blog .

    But how does Dolby technology relate to other standards? In 2016, the UHD Alliance developedThe new standard UHD Premium. Televisions that meet this standard, support 4K video, can give a brightness of at least 1000 nits, etc. This specification stipulates the use of different standards, including SMPTE ST.2084 and 2086, but the exact technology to be used depends on the choice of the manufacturer. Dolby Vision technology TVs must be labeled with a special logo. A list of specific devices is presented on the Dolby website in the Products tab .


    In order to see the HDR image, you need a device that supports this format. SDR TVs are limited to the Rec.709 standard, and the image on them looks fainter. LCD and OLED displays may reflect the DCI-P3 cinema standard used by the HDR10. But Dolby Vision supports the Rec.2020 standard, which makes the color more voluminous (of course, this is a subjective assessment).

    Theoretically, a display that fully complies with this standard could reproduce the full color saturation, which is 75% of the visible color spectrum. Only here there are no TVs that can fully convey such a color space. And today, Dolby Vision TVs, like the HDR10, only support about 90% of the wide color gamut of the DCI-P3 standard (whichis 42% of the visible spectrum).

    So which displays are more suitable for Dolby Vision? There is no single answer to this question. OLED TVs have one indisputable advantage - the perfect black level, which helps to achieve the desired contrast. On LCDs, black looks brighter. In addition, it was difficult to get a rich color on them, because of the filters used, which simply made the color darker, not brighter. But in modern LCD-TVs to achieve a wider color range (WCG) turned out thanks to the " quantum dots " (although at the moment it is rather a marketing name), therefore, Dolby Vision technology is quite compatible with these two types of displays.

    But another difference that can be seen on the existing equipment is the difference in peak brightness. Dolby Vision can use brightness up to 10,000 nits, and devices with HDR10 have enough brightness of 4,000 nits. Dolby Vision can adjust to the screen of any brightness level, but it turns out that according to the characteristics of peak brightness and color spectrum this technology is more promising.

    A little more about color and brightness. On conventional televisions, 256 shades (8 bits) are available for each of the three primary colors. HDR uses 10 bit sampling, which is 1024 shades for each color. And the color depth of Dolby Vision images reaches 12 bits, although 10-bit sampling is recommended for home viewing. Due to this, bright areas begin to stand out and are perceived as more realistic. Compare the image of HDR10 and Dolby Vision on the example of a frame from “Mad Max” here .


    But the main difference between these two formats is not what devices are required for their transfer. Dolby technology is built in at all stages from content production to the moment of playback on a specific screen. During the creation of video content, the director and colorist work on it separately to achieve the desired colors. And the difficulty with HDR TVs is that they can change the palette at their discretion (depending on the algorithm). And guess what the picture will see the end viewer is almost impossible.

    Dolby Vision solves this problem in the following way: when creating video content, colorists can use a control monitor developed by Dolby. Later, along with the signal to the TV that supports this technology, metadata is transmitted that tells the TV what the picture should be.

    Unfortunately, there is not a lot of suitable content, but as we have already said, Dolby Vision and HDR10 are based on one ST.2084 standard. Therefore, content producers can first create videos in the HDR10, and then add dynamic metadata for Dolby Visio.

    How Dolby technology influenced Star Wars: The Force Awakens:

    But it is not necessary to wait for the release of new paintings. Many films shot in the last 10 years have a much wider dynamic range compared to what televisions were capable of displaying. Therefore, even old movies on new devices can "play with new colors."

    Many streaming studios already support Dolby Vision, for example, Amazon Prime Video, Netflix and Vudu. And in 2017, a UHD Blu-ray player with Dolby Cinema technology will be released. Find out which films were removed from the Vision Dolby and Dolby support the Atmos can be here , and to choose what to look at strimingovyh platforms can be directly on the site Dolby on Movies & TV tab.

    PS Another fresh stuff on our GT blog -Entertaining music: Number 5 and a little bit about how the usability and the programmer “see” the music .

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