What you should know about HDR and Dolby Vision

March 10, 2020 | Grading & Production

High Dynamic Range (HDR) is considered one of the most important technological trends in the television, film and cinema sector. HDR provides greater colour depth and brightness range of the captured images. Thanks to HDR, image reproduction is even more realistic.

Quite a few consider the quality leap from SDR (Standard Dynamic Range) to HDR to be one of the most significant improvements in motion display in recent decades, alongside the increase in resolution. Therefore, HDR is also one of the most frequently advertised features of new TV sets. On the consumer side, various formats such as HDR10, HDR10+ and Dolby Vision compete with each other.

In the following article, you will learn what the technical features of HDR and Dolby Vision in particular are, what advantages Dolby Vision offers and what else you as a filmmaker should know in this environment. Magenta TV from Wiesbaden is an expert in HDR post-production and your partner in editing, mastering and color grading of HDR film material.

What is HDR?

The abbreviation HDR stands for High Dynamic Range. It is a technique that delivers high contrast images, usually in combination with higher colour depth. The image representation approximates the vision of the human eye and the actual brightness values in nature. Dark picture elements actually appear black and bright elements radiate intensively. If one looks at the brightness measure of the image representation, the so-called luminance usually indicated in Nit (candela per square meter - cd/m²), this becomes specially clear. Conventional television pictures are limited to a brightness of 100 Nit. Some SDR televisions reach up to 500 Nit, but under certain circumstances they display the 100 Nit picture material with brightness distortions. Modern HDR televisions already reach 1,000 Nit and more. In the future, picture reproduction with up to 10,000 Nit (PQ transfer characteristic) should be possible.

The colour space that can be displayed is also increasing. In theory, conventional SDR mostly uses eight bits for up to 256 different gradations of the primary colours red, green and blue. This results in 16.7 million displayable colours. With HDR formats such as HDR10 or Dolby Vision, the bit depth per channel is ten or 12 bits. With 10 bits, up to about 1 billion, with 12 bits up to about 69 billion different colours would be theoretically possible. However, the representation of colours is limited by another factor in video technology - the colour space. While the ITU-R BT.709 standard currently displays approx. 40% of the colours visible to the human eye, the ITU-R BT.2020 standard will in future display approx. 75%.

In summary, the combination of high-contrast images with an extended colour space makes the HDR experience a true movie experience.

Where and how can HDR currently be experienced?

HDR can already be experienced today. Numerous series or cinema films have been mastered in HDR. Provided an HDR-capable television or monitor is available, these series and films can be streamed via streaming providers such as Netflix or Amazon Prime Video.

Blu-rays with HDR film material are also available, which can be played with a corresponding player and TV. In addition, there are the first Dolby cinemas that implement the Dolby Vision specifications in movie playback. In the computer environment, modern game engines, graphics cards and monitors support High Dynamic Range.

What is HDR10?

One of the first and most widely used HDR formats on the consumer side is HDR10. The abbreviation "HDR10" stands for High Dynamic Range with ten bit colour depth. It is a static HDR format that delivers the metadata for color representation statically and only once defines what contrast range a complete film should have. This means that individual images cannot be adjusted individually, but the basic data for the complete film remains the same. Although HDR10 delivers a better picture than SDR, it does not allow different metadata for individual scenes during playback in a different contrast ratio. HDR10 is a license-free standard and is supported by many manufacturers and content providers.

What is Dolby Vision?

Dolby Vision is an HDR format developed by Dolby Laboratories that is the first to enable dynamic data delivery, allowing the brightness and color of scenes and frames to be adjusted to suit individual needs. By mastering and color correction / color grading, individual contrast values can be determined for each film frame. This prevents dark scenes in a film with many bright scenes from dropping in the quality of the color and contrast display.

The metadata for Dolby Vision is generated by colorists and editors during mastering and color correction / color grading. This allows the image to be delivered as originally intended by the filmmaker. The colour depth for Dolby Vision is 12 bits.

What is HDR10+?

HDR10+ is based on HDR10 but, like Dolby Vision, allows dynamic data delivery and thus individual adaptation of individual scenes for playback. HDR10+ was originally introduced by Samsung and Amazon in 2017. Other manufacturers such as Panasonic or film studios like 20th Century Fox also support the format. As with HDR10, the color depth of HDR10+ is ten bits.

The main differences
between Dolby Vision and HDR10+

Although both HDR10+ and Dolby Vision are HDR formats with dynamic data delivery, Dolby Vision offers much more in terms of workflow for filmmakers and output results for consumers.

The technical parameters can be considered almost identical today, as today's 1000 Nit TVs are considered HDR-capable. The latest models reach 2,000 to 4,000 Nit and sometimes more. The possibilities of the TVs regarding colour depth are also limited. Displays that display twelve bits of colour depth and support the modern BT.2020 colour space hardly exist.
However, two aspects already make a significant difference today and will continue to make a significant difference in the future.

For filmmakers, DolbyVision has developed a workflow that makes the HDR footage available in the most efficient and best possible way for both SDR and HDR devices with a certain nit number. On the consumer side, and thus on the playback side, the hardware data of the display is matched and the most suitable trim including dynamic metadata is played.

Learn more about the Dolby Vision Workflow >>

Another difference between Dolby Vision and HDR10+ is the licensing model. Dolby Vision is a Dolby Laboratories format and therefore requires a license. HDR10+ is a license-free HDR format.

The competition between HDR10+ and Dolby Vision

Currently, the two dynamic HDR formats Dolby Vision and HDR10+ are competing in the market. Samsung introduced HDR10+ in 2017 in partnership with Amazon to compete with Dolby Vision in a royalty-free format. Other companies such as Panasonic and 20th Century Fox also support the HDR10+ format.

Some television manufacturers such as Samsung or Panasonic initially relied exclusively on HDR10+, others such as LG or Sony on Dolby Vision. In addition, many manufacturers are also dual-track and support both formats. In the meantime, Panasonic, for example, also offers Dolby Vision. It is not yet clear whether one of the formats will prevail. Some experts assume that both formats will continue to exist in parallel, others assume that Dolby Vision will prevail. In the area of streaming providers, Dolby Vision has gained Netflix and Apple as allies.

They already stream numerous series and formats in Dolby Vision. In the meantime, more and more members of the HDR10+ alliance are also including Dolby Vision in their portfolio and are focusing on multi-HDR. Even 20th Century Fox, one of the founding members of HDR10+, is now releasing its first films in the form of 4K Blu-ray in Dolby Vision. This could be a sign that the HDR10+ alliance is crumbling.

Requirements for HDR on the television set at home

Similar to the introduction of the high-definition film and television formats HD and Ultra HD, HDR requires the adaptation of technology from film production and distribution technology to playback and display devices. Televisions must be HDR-compatible and be able to reproduce the moving image in the respective HDR format. Of course, film and television studios must produce the content in High Dynamic Range.

Ultra HD Blu-ray can store the additional data required for HDR and play it back via a Blu-ray player. The connection between player and display device is provided by HDMI, which supports both HDR10+ and Dolby Vision as HDMI 2.0. If HDR is to be received via conventional television channels, the transmission and reception technology must also be adapted accordingly. Streaming providers must provide HDR content via their streaming platforms.

Challenges of HDR in linear live TV

Linear live TV faces special challenges due to High Dynamic Range, since the HDR signal must be delivered in real time. It cannot be processed in advance for TV broadcasting and adjusted in colour and contrast as in film productions.

A live production may have to provide content in HD-SDR, HD-HDR, 4K-SDR and 4K-HDR simultaneously. The corresponding 4K-HDR production techniques have to be integrated by the production companies into their production environment, which leads to additional costs. Solutions now exist to produce 4K-HDR, 4K-SDR, HD-SDR and HD-HDR content simultaneously in a single workflow. One solution for HDR in live TV is the HLG (Hybrid Log Gamma) developed by the BBC (UK) and NHK (Japan). HLG will be used as early as the 2020 Olympic Games in Tokyo and will bring live images in up to 8K-HDR to TV sets. The standard is not fully backward compatible as the color space has to be converted.

SDR and HDR devices receive the same 10-bit signals, but interpret them differently. The advantage of this technique is the saving of bandwidth and expensive satellite capacity. The disadvantage is the unpredictability of the reproduction. The creative intention of the filmmakers is probably not reproduced correctly.

It is important to know that HLG is a standard for broadcasting and does not yet compete with HDR10+ or Dolby Vision in this environment. HDR10+ and Dolby Vision are still reserved for streaming services and Blu-ray technology.The majority of UHD TVs are already HLG-compatible. In general, it can be assumed that most HDR-compatible TVs produced after 2017 will be suitable for HLG. When and how Dolby Vision and HDR10+ will come into linear TV is not yet foreseeable.

Advantages for filmmakers through HDR

For filmmakers, HDR offers the great advantage that motion pictures become even more realistic and offer much greater dynamics in brightness and color representation. The result is a lively film experience with great colour depth and high contrast ratio. The colorist can rework each individual scene as he or she imagines the image and communicate this to the display device via the metadata. On the consumer side, the viewer receives the best possible picture for his or her end device. More about HDR in the postproduction >>

Benefits for filmmakers by choosing Dolby Vision as HDR format

Filmmakers who rely on Dolby Vision for High Dynamic Range are given powerful creative options in addition to twelve-bit colour depth and luminance of up to 10,000 nit.

Films can be adapted to the producer's ideas and the dramaturgy of the film by means of colour correction / colour grading frame by frame and scene by scene. Even if today's display devices such as televisions are not yet capable of displaying 10,000 Nit and a colour depth of 12 bits, with Dolby Vision filmmakers are opting for a future-proof HDR format.

In addition, in the Dolby Vision workflow, both the HDR master and the SDR master can be created efficiently and creatively controlled. On the consumer side, the broad support of Dolby Vision offers the advantage of an equally high-quality film experience on different platforms and end devices. More and more device manufacturers are opting for Dolby Vision and numerous streaming services as well as TV and film production companies are choosing Dolby Vision.

Conclusion

It is undisputed that High Dynamic Range will revolutionize the picture quality and movie experience in the TV and film industry. In terms of dynamic formats, the license-free HDR10+ and Dolby Vision, developed by Dolby Laboratories, are currently competing with each other. Numerous devices such as televisions or Blu-ray players support HDR. Already today, HDR and Dolby Vision content can be enjoyed via various streaming services or via Blu-ray. There are a number of indications that Dolby Vision will be able to prevail over the competing format. It opens up enormous creative possibilities for film-makers. With Dolby Vision, filmmakers are choosing a powerful and future-proof format

  • High Dynamic Range will revolutionize the picture quality and movie experience in TV and film

  • In the field of dynamic formats, HDR10+ and Dolby Vision are currently competing with each other

  • You can already stream content with HDR and Dolby Vision or enjoy it via Blu-ray

  • There are several signs that Dolby Vision will be able to prevail over the competing format

  • It opens up enormous creative possibilities for directors, producers and film studios

  • With Dolby Vision, filmmakers are deciding on a powerful and future-proof format


Magenta TV - Dolby Vision zertifiziert
Dolby Vision Workflow

Magenta TV in Wiesbaden is the first Dolby Vision-certified post-production company in Germany to offer you an efficient and future-proof workflow, providing film production according to the ideas of producers and directors in the best possible way.



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