The Xiaomi 2021 spring new product launch conference was held on March 29/30, and four smartphones of the Xiaomi Mi 11 Pro / Ultra / Lite and Xiaomi Mi MIX FOLD were released. All these models support Dolby Vision format, which can bring better video performance.
Xiaomi published an article today detailing the HDR format of Dolby Vision. In general, this format means that the amount of information recorded by a single pixel is larger; it provides a higher dynamic range and a wider color gamut; the theoretical brightness can reach 10000nit and it supports 12bit color depth. At present, mainstream smartphones have popularized high refresh rate screens, and many flagship models also support 8K resolution video shooting. The Dolby Vision HDR format complements the last shortcoming of picture quality.
Xiaomi said that due to the limitations of traditional video transmission and cinema standards, most of the video content we have seen has been produced and played back within a relatively narrow color gamut and brightness range for a long time. Say, most common ones currently are in the SDR standard. The TV and Blu-ray content has a maximum brightness of 100 nits and a minimum brightness of 0.117 nits. However, the color and brightness range of the natural world is wider than the color and brightness range supported by most current broadcast, blue light, and cinema systems, and the brightness gap between bright and dark parts has reached 100 times.
Such a brightness and light-dark gap is far beyond the range supported by the traditional SDR format. It is reflected in the eyes of the audience that the color is missing, the black is white and the dark part does not go down, and the highlight part is dim and not bright enough. The upper limit of SDR content has been lower than the brightness that the current playback device can provide. When the playback device displays SDR content, the simple solution is to simply and roughly stretch the brightness, the surface brightness is increased, but the black field display is worse.
Dolby Vision vs HDR
In the article, Xiaomi showed the simulation effect of the difference between the Dolby Vision format and the traditional SDR content. The Dolby Vision HDR format can fully retain the details of highlights and shadows, and the dynamic range is better.
In addition, the color content that was lost in the past beyond the color space will also be retained in the Dolby Vision format. The most important point of Dolby Vision is to support dynamic metadata. The so-called dynamic metadata is the ability to individually set the most appropriate brightness, contrast, color and other picture effects for each scene of the video content in the unit of scene, instead of using a fixed parameter to run through it. This is also the most important difference between Dolby Vision and HDR10.
Dolby Vision can help content creators to meticulously grade each scene of film and television dramas to realize their creative intentions. Dolby Vision format content has the application of Dolby Vision technology in production, distribution and terminal playback.
As a reminder, the Mi 11 Pro and Mi 11 Ultra have a peak brightness of 1700nit, support 10bit color, and have a 2K resolution + 120Hz refresh rate, which can well realize the playback of Dolby Vision format content. The Xiaomi Mi 11 Lite has an FHD+ resolution and a global brightness of 800nit, but it also supports P3 wide color gamut and 1.07 billion color display.