4-Up Set-Top Box NIWeek Demonstration

At NIWeek 2012, one exhibition demonstration showed a test system for Internet protocol television (IPTV) set-top boxes for both a production application and picture quality analysis.

1. IPTV Set-Top Box Test Demonstration Video
2. Demonstration Explanation
3. Preparing for the Future of Multimedia Test
4. Related Links

IPTV Set-Top Box Test Demonstration Video

Demonstration Explanation

The device under test (DUT) for this multimedia test demonstration is an Amino A140 IPTV set-top box, which streams in multimedia content over the Ethernet port and converts it into various multimedia interfaces. 

Figure 1. System Diagram of the Hardware for the Set-Top Box Tester Demonstration

This demonstration breaks into two parts: one showing a production line-styled test of six interfaces off the IPTV set-top box and the other showing objective, automated test of the picture quality performance of the IPTV set-top box on its HDMI signal. 

Production Test of the IPTV Set-Top Box

In this test, the NI PXI-based multimedia test system tests six interfaces on the IPTV set-top box:

• High definition multimedia interface (HDMI)
• Component video
• Composite (RS170) video
• Optical SPDIF digital audio
• Analog audio
• Internet connectivity

Figure 2. An NI LabVIEW Front Panel Showing the Status of the Various Multimedia Interfaces Under Test on the Device Under Test

This demonstration uses NI TestStand, a powerful sequencing program for production test applications, as the main test engine that pulls in different code modules in parallel to optimize hundreds of measurements and analysis. Check out more on TestStand.

Figure 3. Part of the Operator Interface on the LabVIEW Front Panel Showing the Parallel Test Architecture and Status of the NI TestStand Sequence

The full IPTV set-top box test system contains the following main elements:

• NI PXI system, including various PXI instrumentation modules to match the various multimedia interfaces under test
• NI BNC-2178 VideoMUX for switching through the four composite and 12 component video signals coming from the set-top boxes
• NI CB-2180 digital audio accessory for the optical SPDIF 
• Touch screen for demonstration purposes.

Figure 4. A LabVIEW Front Panel Showing the NI Test Instrumentation Status for the Various Multimedia Interfaces Under Test

This test system performs hundreds of measurements on the set-top boxes including:

• Color Bar to ensure accurate reproduction of colors coming from the video
• Single Tone audio tests to ensure all audio channels are functional
• Timing measurements on the analog video channels to ensure the signals are formatted properly for each video standard 

Capturing the raw waveforms and analyzing these from scratch might take months of development for a team. By using National Instruments hardware and software, a single engineer can now develop a full multimedia test sequence in a matter of hours or days, which saves a significant amount of time and money for the company.

Picture Quality Analysis of the IPTV Set-Top Box

With the introduction of high-definition audio and video, multimedia signal paths increasingly undergo compression and decompression or transcoding before reaching the eyes of a consumer. Consider for a moment the amount of compression that takes place in getting 1080p/60 Hz high-definition content over a standard home Internet connection (Figure 5).

Figure 5. Comparison of the Original Data Bandwidth of High-Definition Content With the Bandwidth of a Standard Home Internet Connection

Clearly, this substantial compression can cause many problems for video or picture quality issues in the form of defects such as visual or audio artifacts, dropped frames, pixelation, and lip sync. Previously, such defects were tested manually by human operators or engineers. However, because human testers can make only subjective, nonreproducible judgments, they may let low-quality products slip by, which inflicts costly returns on their organizations.

But with NI Picture Quality Analysis software, you can create objective, high-throughput, and reproducible tests for these kinds of defects while automating the acquisition and analysis of the incoming multimedia stream using the same PXI hardware in the production test demonstration.

In addition to the set-top boxes which decode the compressed signal being tested, another device that needs to be tested is the device encoding the signal. With each new generation of compression algorithms and hardware, codecs like MPEG2, H.264, H.265, etc. need to be tested for performance.

This demonstration shows different aspects of the tools and tests around picture quality, ranging from the basics of referenced picture quality tests to simulating defects and the resulting picture quality metrics from them.

Figure 6. Screenshot of the LabVIEW User Interface Showing a Low-Quality Test Stream, a High-Quality Reference Stream, and the Resulting Picture Quality Measurements

Preparing for the Future of Multimedia Test

Over the past several years, the consumer electronics industry has been flooded with multimedia featuring higher resolutions, faster refresh rates, and deeper colors. Demand for these features is only growing, especially in the world of mobile devices. On top of that, traditional multimedia devices, such as set-top boxes, have added new technologies such as wireless connectivity.

Test engineers struggle to integrate testing new technology into their processes without significantly increasing their test times and overall test costs. Multimedia outputs on new devices present one of the most significant test challenges in maintaining low test times because a video signal contains much more data than most other signals. Many manufacturers use traditional box instrumentation for these measurements, but with these instruments, they must transfer data over slower buses like GPIB, USB, or Ethernet, which can often take several seconds or even minutes for a single measurement. Besides the low data throughput, traditional box instruments can be challenging because of the difficulty in automation and the lack of flexibility due to their fixed functionality. The traditional box instrument approach does not scale well for testing these new devices in terms of cost and integration.

Figure 7. Mobile devices present one of the most complex testing challenges due to their many I/O points and need for getting to market fast

By choosing a test platform that incorporates all of the relevant I/O points in a high-performance, modular system, a company can gain a competitive advantage by maintaining a high level of adaptability and quality in test.

Related Links

View a pre-configured test system for multimedia devices

Evaluate NI multimedia test software: NI Picture Quality Analysis, NI Video Measurement Suite, or NI AudioMASTER

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