Renard Jenkins evaluates UHD codec performance with the Video Clarity ClearView 4K system.
ARLINGTON, VA.—With more than 350 member stations, PBS offers all Americans the opportunity to explore new ideas and new worlds through television and online content. Our 2013-2014 season brought the fifth-largest primetime household rating among all broadcast and cable networks. In 2014 alone, Americans viewed more than 4.5 billion videos across all PBS digital platforms. Ours is a massive broadcast and content distribution operation, with much of the content produced by independent entities and member stations. The goal is to deliver a solid product to our member stations so they can provide a topnotch experience for their viewers.
GETTING READY FOR UHD
In order to do this, we have to protect our product from degradation as it goes through processing and distribution. We’re also looking at advanced formats, such as 4K, and testing those new technologies to determine what combination of products, codecs, and methodologies will yield the best quality for the lowest bandwidth.
A big part of our testing involves new compression standards such as HEVC. We need to test HEVC along with H.264, J2K, and VP9 codecs to determine our best approach to 4K and UHD delivery. There are many directions we could go, and this makes testing all the more critical.
Currently, we’re using Video Clarity’s ClearView 4K analyzer in our Advanced Formats Center at National Public Radio. This is a collaborative effort with our public media partner in which we’ve created a test environment with a “mini ecosystem” of advanced formats and production and distribution methods. ClearView 4K allows us to test the quality of 4K video when processed with different encoding technologies. Besides being the first analyzer to deal with 4K and other advanced formats, the ClearView 4K lets us do several things that we were hard-pressed to do before.
Its A/B split-screen presentation allows us to do side-by-side comparisons of different compression codecs, and even different “flavors” of HEVC. We can make quality measurements throughout the processing chain, from origination through delivery using different encoding methods at various bit rates, frame rates and other variables. ClearView 4K’s complete set of full-reference tests allows us to test any given scenario with complete confidence.
HIGH FRAME RATE TESTING TOO
The ClearView 4K can also test 4K UHD content at high frame rates, including 60 fps and greater, and it provides a set of audio tools that lets us analyze how 4K and UHD codecs affect audio—a critical part of the viewing experience.
Video Clarity’s ClearView 4K also saves us time and money by doubling as a remote testing system. Not only can we use it in our Advanced Format Center, but our distribution team can access the box anytime via VPN to perform remote tests of their own.
The testing results obtained with Clear- View 4K are helping us to develop and recommend production techniques that our independent partners can follow for 4K origination. These results are also helping us understand the effects of 4K encoding technologies on program delivery so that we can continue to refine the audience quality of experience.
Renard T. Jenkins has been with PBS for four- and-a-half years and has worked in broadcasting for 28 years. He may be contacted at rtjenkins@pbs.org.
For additional information, contact Video Clarity at 888-748-8072 or visit www.videoclarity.com.
