New Wireless Video Quality Assessment Tool from VeriWave

WaveVideo helps enterprises, service providers, and manufacturers quantify and visualize 802.11n network and device HDTV-readiness.

802.11n’s high data rates can support many demanding multi-media applications, from video conferencing at the office to media distribution throughout the home. But ensuring quality HDTV delivery to tens or hundreds of Wi-Fi devices in a variety of potentially RF-hostile venues is no small feat. Success requires careful product engineering and network planning—and the ability to test network and client performance in a meaningful, scalable, and reliable manner.

To help Wi-Fi device manufacturers, media service providers, and enterprise IT staff meet this challenge, VeriWave this week released WaveVideo. At $7500 per licensed WaveTest port, this plug-in extends VeriWave’s WaveQoE suite to send hundreds of independent HDTV, SDTV, or VGA streams through APs, media gateways, set-top boxes, and other network/client devices.

What you see is what you get

“Our tests allow users to precisely measure streaming video quality and to actually see what viewers will see on their end—from pixilation to video jitter and loss of synchronization between audio and video,” said Eran Karoly, VeriWave’s VP of Marketing.

Media Delivery Index (MDI) scores are used to quantify each stream’s quality. But since abstract scores can be difficult to grasp, WaveVideo also offers a side-by-side replay of any video stream, captured before and after a system under test. By combining objective and subjective test results, testers can get a feel for real-world impacts and how they translate into service level objectives.

Furthermore, because video is typically delivered over shared WLANs, WaveQoE can mix video clips (selected from an included library) with other application flows to create realistic test traffic. Using this kind of methodology, developers, installers, and IT admins can quantitatively and qualitatively assess the video-readiness of network infrastructure (e.g., switches, APs, gateways) or clients (e.g., set-top boxes, IP cameras). If defined scores are not achieved, changes can be made and identical tests can easily be repeated to evaluate effectiveness.

Covering all the bases

According the Craig Mathias, principal at Farpoint Group, an automated test tool like WaveVideo can benefit many different WLAN engineering efforts. “Anyone building products across the value chain (chips, boards, systems, and integrated installations) will need this,” said Mathias. However, test configuration depends upon the type of system under test.

Specifically, WaveVideo is not a stand-alone test tool. Every WaveVideo test starts with a VeriWave WaveTest engine—a traffic generation chassis outfitted with network blades. Dual Ethernet devices like media gateways can be tested using GigE blades, while 802.11n devices like APs can be tested using either SISO or MIMO 802.11abgn blades.

Video traffic may be generated in either downstream or upstream directions – for example, distributing HDTV or SDTV streams through a gateway under test to simulated clients, or receiving VGA video feeds from an entire test network of wireless cameras. To measure the impact of video on other applications and vice versa, competing “ecosystem” traffic can be injected by another WaveTest blade.

Pre-defined video traffic can be generated in the upstream direction by running WaveAgent executables on each client under test. WaveAgent currently supports Win32, WinCE, and Linux-based clients. “Fortunately, most of the devices we’ve seen thus far run some variation of WinCE or Linux,” said Karoly. “But we can tailor WaveAgent to run on [each customer’s] set-top box.”

The bottom line

WaveVideo builds upon VeriWave’s WaveTest, WaveQoE, and WaveAgent products while providing the added depth and simplicity really needed to optimize video network design and trouble-shoot end user experience.

Once these pieces have been assembled, users select a video clip, specify a minimum acceptable service level, and start the test. After the test is completed, reports document per-stream results, including coding, frame rate, aspect ratio, average latency, average jitter, MDI score, and pass-fail outcome (i.e., MDI above/below expected service level). Troubled streams can then be investigated by right-clicking to view a bar graph of corrupted I/P/B frames (plotted at 10 second intervals) or replay video in and out (viewed through any standard VLC player).

“High quality video is clearly the next ‘killer app’ for Wi-Fi and many vendors and service providers have been waiting for 802.11n to become officially ratified to fine-tune new offerings,” said Karoly. Clearly, VeriWave is hoping that WaveVideo will prove to be just the ticket for this emerging, but potentially very large audience.

Lisa Phifer owns Core Competence, a consulting firm focused on business use of emerging network and security technologies. A 28-year networking industry veteran, Lisa has been involved in the design, implementation, and testing of wireless products and services since 1996.

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