As video equipment becomes more complex and release cycles shorten, quality assurance (QA) and quality control (QC) testers have less time to test more features. Testers often scramble just to perform basic feature testing. So what happens to video quality testing? How do you know if your system is introducing artifacts and distortions?
Video quality testing in design and manufacturing
With the advent of digital television (DTV), video processing has changed significantly. Almost all videos are compressed, scaled, broadcasted or IP delivered, and decompressed. This has created many opportunities for video technology manufacturers.
These opportunities appear at breakneck speed, however. The average time to market from concept to delivery for high-tech equipment has shrunk from five or six years in the '90s to one or two years today. The first manufacturer to introduce a high quality product gains a sustainable competitive edge. As companies race to introduce more features in less time, the controlling factor for product introduction has shifted from the speed of development to the speed of validating that the system works.
To answer this demand, some testing organizations have adopted scripting in hopes of saving time. While running test scripts is faster than manual testing, how do you automate video quality analysis? Unfortunately, video quality testing has not kept up. Most companies employ testers with "golden eyes" to verify that the quality is acceptable. In addition, many talented testers prefer manual testing so that they can spend their time devising creative test cases rather than becoming proficient with complex scripting languages.
Video Clarity created a breakthrough approach to video quality testing that empowers equipment manufacturers to increase coverage and spend more time on creative testing. This technology, termed ClearView, is a scriptable, automated video quality testing system. ClearView combines an uncompressed video server, a video recorder, a video player, and a quantitative video quality scorer. By providing all of these in one unit, ClearView becomes a complete, testing system for advanced video quality scoring and comparisons.
ClearView video quality analysis
Video Clarity's ClearView system offers a set of video quality analysis tools for software developers, hardware designers, QA/QC engineers, video researchers, and production/distribution facilities. ClearView plays, records, displays, and analyzes video sequences. The device can capture video content from virtually any source-file or digital or analog source such as SDI, HD-SDI, DVI, VGA, HDMI, component, composite, or S-video. Regardless of the input, ClearView can ingest and convert it to fully uncompressed 4:2:2 Y'CbCr, 4:4:4 RGB, ARGB, or RGBA. This allows codecs to be easily compared and scored relative to each other.
ClearView provides many mathematical models that approximate results of subjective quality assessment. Objective mathematical methods are classified based on the availability of the original video signal, which is considered to be of high quality:
- Full Reference Methods (FR)
- Reduced Reference Methods (RR) and
- No-Reference Methods (NR)
Have you ever wanted to compare your H.264/VC-1 & MPEG-2 algorithms relative to each other? Now you can. You can also measure video delay and audio/video lip-sync.
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Figure 1: ClearView GUI with pass/fail results
NEXT: Digital compression issues
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