Topics covered in this article:
- Video output settings
- HDR and Target mastering displays
- Waveform monitors / scopes
Video I/O Settings
It is important to set up the video output, networking, and routing within the facility to support the highest-quality video for HDR color grading and monitoring.
- Progressive or Progressive Segmented Frame Scan – It is recommended to create Dolby Vision content using a Progressive frame rate (1080P, 2160P, etc.).
- Color Encoding – It is recommended to create Dolby Vision content using RGB color encoding.
- Video Subsampling – 444 video subsampling is recommended for highest color fidelity and reproduction.
- Signal Range / Data Levels – Dolby recommends using full range video for Dolby Vision content creation. Dolby Vision metadata when exported from the color corrector will always indicate full range unless the XML is manually modified by the user.
Bit Depth – We recommend using the highest possible bit depth while creating Dolby Vision content. Most color correction systems work in 16 bits internally but will be limited to 12-bit video output for monitoring.
[Refer to the article How-To: Dolby Vision Legal Range workflows for home distribution for more information about legal/full range workflows and deliverables]
It is recommended to use a video output card that supports the highest-quality RGB, 444, 12-bit, full range video out of the color correction system.
Monitoring for HDR grading and Dolby Vision
It is important to set up the right monitors for the Dolby Vision content creation process. It is popular practice to use two separate monitors, side by side for Dolby Vision work. Some facilities and colorists prefer to work with a single monitor to avoid any discrepancies that may occur between two physical displays. It's important to match the input settings of these displays to the output settings of the video I/O of the color grading application. Ensure that both the mastering as well as the target display are set to full range.
Single monitor or dual monitor setup
Some colorists prefer to use two separate displays to better match the mapped version to the intended HDR grade and to continuously check the mapping. Using a single display eliminates potential impacts of using a different display technology on one or the other display and for sure both have the same size. As the size of a display has an effect on the perceived contrast this effect might be taken into account.
The HDR Mastering Display
The HDR Mastering Display is the primary display that is used to monitor the progress of the HDR grade. This display must be a reference-grade monitor that can display images in P3 (or Rec2020), D65, RGB, 444, 10/12bit, and full range. The monitor must have a high contrast ratio with deep blacks and the ability to display highlights up to at around 1000 nits.
[Refer to the article FAQ: What monitor should I use for creating Dolby Vision? for more information about monitoring in HDR]
The Target Display
The target display will be required to monitor the output of the eCMU/iCMU during the Dolby Vision trim pass. The target display must be able to display Rec709, 100-nits, Gamma 2.4, 10/12-bit, full range video as SDR/100-nit trims are mandatory for all Dolby Vision projects. Some studios request additional trims at 600-nits, in which case the target display will have to be able to display P3/Rec2020, 600-nits, PQ, 10/12-bit, full range video as well.
While many facilities and colorists prefer to use a dual monitor configuration, it is also possible to work with a single monitor that can be switched between HDR and SDR modes, which would serve as the HDR mastering monitor as well as the SDR/HDR target display.
The surround illumination has a huge impact on how we perceive contrast and color. The surround illumination should come from a light source that matches the color temperature of the display. Usually this is D65 for both HDR and SDR. The surround light level is specified to be at 5 nits for SDR and HDR. Please refer to SMPTE ST.2080-3 for more info on viewing environment requirements.
Waveforms and Scopes
It is highly recommended to use PQ Waveforms and Scopes to monitor the Dolby Vision content creation process.
While grading the HDR master, it is important to monitor the image on the HDR Mastering Reference Monitor as well as the scopes, as the monitor/display will not be able to display the entire PQ range of 0 to 10,000 nits.
During the trim pass, we recommend using a second set of scopes to monitor the mapping and the response to the trims as they are applied by the colorist.
[Refer to FAQ: What monitor should I use for creating Dolby Vision? for more information on Monitors for Dolby Vision content creation]