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Video Quality Research |
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National and International Standards National Standards: From 1994 to 1997, Institute for Telecommunication Sciences (ITS) personnel played a key role in the development of four American National Standards that can be used for gauging the quality of digital video systems. In 2003, ANSI T1.801.03-1996 was revised and reissued as ANSI T1.801.03-2003. These standards are:
ANSI T1.801.02 provides a dictionary of digital video performance terms and impairments. This standard includes a video tape that illustrates common digital video impairments such as tiling, smearing, edge busyness, error blocks, and jerkiness. Thus, this standard gives end-users and service providers a common language for discussing digital video quality. ANSI T1.801.03 defines a whole new framework of objective parameters that can be used to measure the quality of digital video systems. For a tutorial of the original ANSI T1.801.03-1996 video quality metrics and their application for measuring compressed digital video impairments, see our ANSI Video Quality Tutorial. In 2002, a "General" ITS-developed video quality metric (VQM) was prepared and submitted to the ITU Video Quality Experts Group (VQEG) for independent testing and verification. Of all the international VQM proponent submissions, the ITS VQM submission was the only VQM that was in the top performing group for both the 525-line and 625-line video tests. For the U.S. standard 525-line video test, the ITS VQM achieved a correlation coefficient to the subjective data of almost 95%, near the theoretical limit. These test results are even more remarkable because the ITS VQM submission was a "reduced-reference" measurement system whereas the other proponents submitted "full-reference" measurement systems. The ITS VQM submission only requires approximately 1/20 of the reference data to make a measurement. As a result of these international achievements in 2003, the ITS VQM was standardized by ANSI in July 2003 (ANSI T1.801.03-2003), which replaced the original ANSI T1.801.03-1996. ITU-T Study Group 9 and ITU-R Working Party 6Q have also included the ITS VQM in their Recommendations (see the International Standards section given below). To assist companies and potential licensees in the deployment and use of the patented ITS VQM technology, evaluation software that implements the above national and international standards has been posted on the ITS web site. The fourth standard, ANSI T1.801.04, defines measurement methods for audio delay, video delay, and audio-visual synchronization. These performance parameters are important for interactive (i.e., two-way) telecommunication services. For copies of these standards, contact the American National Standards Institute (ANSI). National Technical Reports: From 2000 to 2003, ITS personnel also helped develop a series of five technical reports (TRs) that have been published by Committee T1 - Telecommunications, Alliance for Telecommunications Industry Solutions (ATIS). These technical reports can be downloaded directly from ATIS:
ITS personnel are active participants in the video quality standards development process of the International Telecommunications Union (ITU). Currently, the most active area of participation is in the joint ITU-R / ITU-T Video Quality Experts Group (VQEG) which is evaluating video quality measurement methods for MPEG-2 and other video services. ITS maintains the VQEG Web Page, the VQEG reflector (ituvidq@green.its.bldrdoc.gov), and the VQEG document archive (ftp://ftp.its.bldrdoc.gov/dist/ituvidq/). Companies and organizations that would like to participate in VQEG activities should send a subscribe message to the above reflector. The "General" ITS VQM, standardized by ANSI T1.801.03-2003 (see above) has also been included in the following two ITU Recommendations:
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