One of the most common picture problems associated with IPTV networks is the random “Blocky” artifacts that occasionally cut through a crystal clear picture like a crayon stroke across a fine painting. As disruptive as the annoying static of two decades ago found on TV screens during lightening storms, these high-tech artifacts can severely frustrate viewers. Today, most viewers are accustomed to very consistent images and the robust quality they receive from current broadcast providers.

Given our conditioned expectations of clear and consistent picture quality, there will be no waiting for the storm to pass. Viewers will not hesitate to call their service providers to complain. An excessive amount of poor picture quality, or even a single instance during an important broadcast, could be enough frustration for a viewer to drop the service and switch to a competitor, or even worse, head back to cable TV. Having a tool that can identify, isolate and diagnose the problem will be key in preventing churn, reducing truck rolls, and of course keep the monthly revenue growing.

Typically these problems come from packet loss, delay or data corruption in the IP transport network. The trouble starts when bandwidth limitations, network stability, or equipment failures cause loss or corruption of the video packets, which ultimately causes the video decoders to fail. Without all of the video data, decoders have no choice but to spit and sputter garbage to the screen.

Identify the existence of a problem
All video problems are at least mildly annoying and very aggravating during important video events like the World Series. Being able to detect perceived quality in real-time or historically is the first step in identifying a low quality IP video broadcast. Spectra2|Video Quality Measurement (VQM) shows a real-time and historical MOS (Mean Opinion Score, a perceived quality metric) for individual video streams. By tracking MOS, a service center can see exactly when the degradation is occurring or verify past problems. Spectra2|VQM can rate the quality of the video stream as would be perceived by the viewer on a scale from 1(bad) to 5 (good), as well as report individual metrics for blockiness, jerkiness, and blur that can help identify the types of problems the viewer is experiencing.

A typical MOS score over time might look like the following:

In this example, Spectra2|VQM is verifying that a viewer is actually seeing video that is less than acceptable during three separate occasions where the MOS score dips below an acceptable value of four. Consistently lower MOS scores over time will statistically indicate the loss of a customer. Tracking MOS over time can eventually be used as a customer barometer indicating how responsive the service group must be in resolving a problem before losing a customer due to poor quality.





Isolate the problem
There are many areas where the quality of service can be affected as video streams traverse a network to the home. Being able to measure and locate the degradations in quality at different positions in the network allows a service group to pinpoint the location of the problem.

By monitoring the video streams at key points in the network, users can determine where the
degradation in quality is occurring.

1. Poor quality at the head-end could indicate actual poor content, or could be an indicator of faulty content or invalid transport encoding. Spectra2|VQM can detect both types of quality degradation.
2. Equipment failure or bandwidth issues at the central office could be detected using Spectra2|VQM transport analysis metrics like packet loss and jitter.
3. Proximity errors with DSL or DSLAM failures can be detected between the neighborhood and the home by monitoring bit error rates and content quality.
4. Finally, network equipment or set top box failure could indicate a problem within the home itself.

Diagnose the problem
Detecting specific problems is at the core of Spectra2|VQM video monitoring. Correlation between MOS and other factors that include Packet Loss, Delay and Jitter along with MPEG transport priority statistics, gives a technician the tools necessary to determine the problem. Integrated reporting analysis tools provide interactive views of all Spectra2|VQM video metrics. Video data capture and decode also ease the troubleshooting activity. Spectra2|VQM allows a technician to view the actual video in progress for a visual indicator of quality.

The ultimate goal will be keeping the viewers pleased with high quality and consistently robust video service that they will refer to their friends. Of course, reducing truck rolls and customer complaint calls will also be crucial to controlling expenses. Spectra2|VQM provides a comprehensive toolset for monitoring video quality metrics and their associated factors that will solve video problems quickly and keep your customers satisfied with this important and exciting new media technology.