Author: Dave Guerrero, VP Technical Services, WLVT-TV
We have been led to believe that in today’s broadcast production environment, quality is determined when employing an automated measurement device analyzing and reporting problems using SNMP traps, email, SMS text and/or etc. The question is whether the information collected, and later generated by these ’Quality Analyzers’ is sufficient to ensure the quality of our content being delivered to our viewers or from a post-production facility.
I have read (and in some cases written) articles summarizing as much. I have found via more years of experience than I care to share, that automated analysis is limited to sets of rules used to determine compliance to a suite of parameters ensuring both standards compliance (quality of service) and subjective criteria (quality of experience). It is very difficult to understand that rules can be written covering every potential image issue: For example, the wrong light temperature shining through a window on the production set.
What I find when looking for a device to ‘monitor my content’ is a variety of products each capable of a particular set of analysis criteria, albeit a few capable of displaying all required analysis criteria. For example, many of the current generation of picture monitors include some rudimentary test and measurement displays in addition to the picture. Other monitors are very heavy on picture and audio bar graphs but offer very little in the features that actually help my operators understand the quality of the image.
I find that the only true means of evaluating overall image quality is somewhat ‘old-fashioned’, and relates to someone actually viewing the content while using this tool called ‘a monitor’ to assist in determining that the image (and signal) produced by the camera or edit system is ready for air. Remember a 3G/DH/SD/2K-SDI or fiber video signal is not just providing an image; the image is carried within the ‘signal’ along with metadata and related information.
I always use the analogy for monitoring audio: Until someone figures out how to place a TOSLink or AES port in my head, I need to hear sound from a source producing analog audio. The same is true with an image. Until my knowledge of images, image artifacts and subjective quality is placed in a device that replaces my eyes and experience, I will need to view an analog representation of the image to determine its quality.
In the world of field production it is imperative, and goes without saying, that a monitoring product offer battery (DC) operation. Field monitors also need to be light weight, include some means to mount on a camera tripod or lighting stand and be rugged. A requirement that is usually overlooked in field monitors is their ability to truly reproduce the camera’s image quality, be it a 4K SDI camera or DSLR with HDMI.
Above all, the field monitor MUST provide the confidence to the production team that the content being captured will survive the post-production process and be acceptable to any level of distribution. A monitor that is not truly producing an image can fool even the best producer while working in the field.
The cinematographer working with the producer may also need to verify that the image’s dynamic range is not compromised. Image attributes clipped on the high or low end cannot be corrected after recording and also must be verified on location. The embedded test and measurement displays are used to monitor exposure/contrast levels.
The field monitor provides a multitude of information for the remote production team. On Screen Display of safe title, safe action, clean aperture, image center, title safe, etc., are not ‘nice to have’ – they are a must have for any professional. Timecode burn (including userbits) and custom source ID are always useful features to look for when acquiring a field monitor.
In post-production, more attributes are verified prior to rendering the final file for distribution (post-production QC). At this point audio and video levels must be monitored for quality, including audible loudness. Metadata may have been added to the final clip, including closed captions, VChip, and second language support.
Today’s technologies across 2K, 4K, HD and other formats require fairly complex monitoring to ensure standards compliance and subjective acceptance by the distribution network. I have found a relatively new ‘standard of quality’ with monitors from Plura Broadcast, a company offering wonderful monitoring products that include every bit of quality and performance needed by field and post-production.
Every production team desires the flexibility of using the same family of monitors in the field as well as in the post to ensure image consistency. Using Plura 9” and 17” monitors in the field; and 32” in the edit suite ensures that there will be no questions from any production team on image quality.
I‘ve seen many companies add a variety of test displays having low quality to monitors; resulting the user purchasing of features, that in the real world, are not of much use. In general today’s waveform monitor is used mainly to ensure proper exposure (no clipping), black level, and gamma. Many video attributes can be corrected in post, however getting the camera exposure correct will go a long way in reducing the amount of time spent correcting the images later.
Plura monitors have a great quality of rasterization, ensuring very usable waveforms, while also offering the ability to present SDI data in a textual format. Not many operators understand that the engineering behind the fact that image data, like the SAV, may be placed improperly, but what he is concerned with is more from a high level – that the camera connected is operating properly (or not).
Audio bar graph displays and the ability to monitor (earpiece) any of the 16 embedded audio signals are expected features in any monitor. However, the Plura SFP model adds CALM certifiable loudness measurement, a must for post-production facility.
The first day I showed a Plura monitor to my production team, they literally would not give it back. They had been waiting for something lightweight and battery operated, offering features of the most expensive monitors. They could now take the monitor out on single camera and/or fly-pack shoots and be assured of the image quality without waiting to return to the office and view in the edit suite.
Unsurpassed quality, simple operation, and flexibility; that’s all they’ve every asked for, and with Plura it’s finally…in the house.