Importance of High-Res Waveform Monitors in UHD/4K Production
By Alan Wheable FISTC, MITOL, Senior Technical Author, Omnitek.
The humble waveform monitor has always been the tool of choice for anyone working in the video industry. Waveform monitors are used for everything from system design, manufacturing, installation setup, outside broadcast, grading, through to quality control. And that’s only to touch on a few areas.
There has been a significant change in demand since existing HD and 3G-SDI waveform measurement technology was developed. There is now a demand for equipment that can cater for all the possible physical interfaces, myriad video formats, new colour spaces and High Dynamic Range. This is just a few of the challenges facing the industry.
With more and more manufacturers developing 4K products and significant program makers demanding all program content be created at 4K with high dynamic range, there is an increased need for equipment to support new production workflows.
Working with HD and 3G-SDI waveform technology may have been a solution in the early days of UHD/4K to display the waveforms from individual square division feeds, but it does not help if you cannot see the combined image at an appropriate size, resolution and correct colour space, or the waveform monitor doesn’t have the required physical connections.
It can be challenging to ensure the quality of UHD/4K program material if the required tools are not available. The importance of waveform monitor technology in UHD/4K content creation and distribution increases with the need to ensure conversions between link types (for example between QL 3G-SDI, 6G-SDI, 12G-SDI, HDMI and IP), between encoding methods (such as square division and 2 sample interleave), between different bit depth formats and between colour spaces (i.e. BT.709 and BT.2020) are correct before even touching on the complexities introduced by images with high dynamic range.
Rather than providing confidence that the picture is present at the correct levels, the waveform display must now be expandable to pixel level to observe any digital level issues (e.g. when converting between 8-, 10-, and 12-bit video), image construction issues (e.g. when converting between link types and encoding methods) and colour space issues that may otherwise go unnoticed on T&M equipment with small, low resolution displays.
Ideally the waveform display needs the ability to view the waveform of the composite image as well as the waveforms of individual links to make it easy to identify issues with 2-sample interleave and square division images that may otherwise go unnoticed in an environment using existing HD/3G infrastructure to deliver 4K/UHD material.
Although some T&M equipment may boast 4K/UHD waveforms, these are often low resolution displays, with sub-sampled waveforms, that give a level of comfort and familiarity but will hide any underlying issues.
What is required is waveform monitor technology that has been designed specifically to meet the exacting needs of 4K/UHD environments while supporting all of the different video formats that will be present in the industry for many years to come. It needs to be able to display waveform, CIE gamut charts and vectorscope instruments to pixel level. This is regardless of the physical link over which it is delivered, and needs to be future-proofed to accommodate the emerging needs of the industry.
The new high resolution waveform monitor available as standard on the Omnitek Ultra XR and as an option on the Ultra 4K Tool Box supports video formats from SD up to 4K/UHD at frame rates up to 60Hz and supports both BT.709 and BT.2020 colour spaces. BT.2020 extends the viewable palette of colours (for 4K/UHD formats above 60Hz) and improves dynamic range and the CIE Gamut display allows this to be viewed.
The region of interest functionality of the waveform display allows it to be expanded to see any digital level issues, image construction issues and colour space issues that may otherwise go unnoticed on some other T&M equipment. This is especially important to anyone working with different colour space material or the conversion of program content from one domain to another.
The Omnitek Ultra XR debuted at NAB 2016 is configured specifically for content creators, colourists, post-production editors and other processors of DI, and working with ultra high resolution UHD images delivered over QL 3G, DL 6G or 12G SDI and HDMI links.
The Ultra XR provides all the traditional tools needed to work with DI – high-resolution waveform display, vectorscope, CIE chart and so forth – but engineered specifically with 4K/UHD in mind. The Ultra XR supports 12-bit 4:4:4 SDI input formats in YCbCr and RGB, along with Wide Colour Gamut RGB – ITU-R BT.2020 and High Dynamic Range (HDR) inputs – ST2084/PQ and Hybrid Log Gamma.
The Ultra XR has the same small form factor as the Ultra 4K Tool Box which makes it ideal for any environment, especially where space, power, and weight need to be kept as low as possible. The range of input, output and monitoring connections mean it can easily integrate into all environments.
The Ultra XR supports SD, HD, 3G and 6G-SDI as standard, with 12G-SDI as an option. The ability of the Ultra XR to monitor different physical links, as well as square division and 2-sample interleaved sources ensures the signal can be viewed and checked regardless of how it actually arrives. This flexibility makes the Ultra XR an ideal fit for existing installations as the technological landscape continues to evolve.
Intuitive user control and monitoring is provided via HDMI, SDI, or web browser connections. The use of an optional mouse and keyboard allows the control surface to be configured exactly as required, and presets can be used to quickly recall previously saved settings.
In addition to the high resolution waveform monitor, provided on the Ultra XR, traditional instruments such as vectorscope are included. Although this basic tool provides a level of usefulness in 4K/UHD applications, other tools such as CIE Gamut charts (supporting SMPTE C, EBU, BT.709, BT.2020, and DCI colour spaces) are provided to ensure the colour space rendition of the image is always correct.
All the waveform instruments can be viewed as tiles, or as full screen, which is ideal for grading and quality control applications where detail is vitally important.
The demand for the best possible user experience has fired up display screen and camera manufacturers to develop equipment that offers the ability to do this. One of the challenges for content providers is to be able to deliver this ‘user experience’.
The tools within the Omnitek Ultra XR and 4K Tool Box are available now to help deliver the best possible user experience.
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