Overcoming QA challenges in smart multimedia device manufacturing with state-of-the-art video testing

Testing requirements of smart multimedia video

Testing of smart multimedia video has grown from analyzing captured image quality to various items and supports specifications including EDID (Extended display identification data)/DDC, HDCP (High Definition Content Protection) and PSNR (Peak Signal to Noise Ratio) and OCR (Optical character recognition) etc. Through the aforementioned tests and standards, video transmission performance and accuracy can be made more consistent for a higher quality product

• EDID/DDC support (Plug & Play system):

EDID (Extended display identification data) is usually kept at the display end EEPROM, which stores resolution and scanning frequency, as well as device brand and serial numbers, supported by the display device.

DDC (Display Data Channel) is a standard specification launched by VESA that informs both sender and receiver of the other’s capacity. Once the display end's EDID data is received at the host, the display and host communicate through the DDC channel to establish the appropriate resolution. This Plug & Play system enables the host and display to detect and set the ideal resolution to avoid manual adjustment by the user.

EDID/DDC’s support of commercially available devices with an advanced image capture card for testing is increasingly important. If the existing EDID / DDC configuration fails to comply with the testing device, the editing and updating capacity of EDID/ DDC are crucial considerations for versatility and expandability.

• HDCP (High Definition Content Protection) support:

Developed by Intel, HDCP is aimed at preventing illegal copying or recording of digital videos when transmitted through HDMI or DVI interfaces. The HDCP mechanism requires both source and display ends to be equipped with built-in HDCP key chips to display any HDCP protected video content, otherwise the user will only see videos with reduced image quality or noisy image. To test HDCP encrypted video content, the image capture card used by the testing equipment must have a HDCP key chip built in.

• PSNR (Peak Signal to Noise Ratio) testing:

PSNR is a popular and widely accepted objective image quality evaluation measure based on the ratio of maximum image signal value vs. noise contained in the image. The higher the PSNR value the better the image quality will be. In general, a PSNR value lower than 30dB represents unacceptable image quality. That is, the PNSR value must exceed 30dB in most cases. Only uncompressed images of high resolution and frequency can help testing equipment owners use the PSNR algorithm for automatic image testing once the image data is acquired.

• OCR (Optical character recognition) testing:

Smart multimedia devices are characterized by their cloud-based remote monitoring & control services. That is, smart multimedia devices rely on networks to fulfill their functions, such as storing data and accessing apps. The device and its display screen must have WiFi streaming for wireless multimedia video playback. As such, the WiFi data, such as IP address and transmission volume, are mandatory testing items. IP address and transmission volume checks were done manually in the past, which often led to unstable results due to inaccurate and/or slow testing processes. Identifying characters with the OCR function improves testing performance significantly by immediately detecting any WiFi data transmission abnormality.

• Automatic video testing is more accurate, efficient and cost effective

The complexity of video testing means that manual video testing can lead to inconsistent results due to subjectivity, eye fatigue and attention deficit, not to mention the fact that some information can only be detected with instruments rather than the naked eye. Automating the testing of multimedia video devices with high-resolution HDMI Video/Audio capture cards supporting multi video I/O interfaces combined with good quality, easy to develop, flexible testing recognition software can lower labor costs and reduce testing errors while enhancing efficiency and yield.

• Two-in-one video testing

Multimedia device video signal testing covers not only video but also audio signals. The video data capture card supports specifications including HDMI multi-channel, one or multiple channel surround sound and high sampling rates. Uncompressed high-zero distortion is another key criterion in selecting testing products as shown in Figure x.

• Software requirements for video testing

Software support for testing may cover image capture, testing and recognition. The key factors for developers are: user friendliness and short learning cycle, enriched API templates, support for popular third party applications including Microsoft DirectShow, NI LabVIEW and Euresys Open eVision, easy testing function customization and easy user interface enablement. Development tools that meet the above conditions can help fine-tune a testing program to meet the requirements of various multimedia devices while improving testing efficiency and automation.

Single Video/Audio capture card for both HD video data retrieval and testing

ADLINK's PCIe-HDV62A high-resolution HDMI Video/Audio capture card features Full HD (1920x1080p) image support, uncompressed, and up to 60 frames per second streaming data capture, integrated multi-source digital audio data capture, HDMI, D-Sub, YPbPr, CVBS/SVideo, AV terminal enriched all-in–one input interface, EDID/DDC programming and updated support, HDCP digital content encryption for PSNR, OCR and image alignment testing for automatic image signal alignment and testing. The PCIe-HDV62A supports HDMI 8-channel uncompressed and surround sound at sampling rate up to 96 kHz for Spdif, RCA/Toslink for fiber optic lossless sound source transmission, enabling video capture by most commercially available multimedia devices, including smart TV streaming dongles, network streaming TV boxes, analog/digital set top boxes, Blu-ray players, KVM image quality control and VGA／HDMI image output testing from notebooks, handhelds and tablet computers.

The proprietary ViewCreatorPro application is included with the ADLINK PCIe-HDV62A and features video and audio recording, color space conversion, and image cropping function testing through simple parameter configuration and GUIs without any coding. It is the perfect tool for easy image capture and configuration verification. Compatibility with Microsoft’s DirectShow enables enriched support for third party software and enhanced flexibility and expandability. Customers may adopt GraphEdit and VLC & AmCap for preliminary tests and evaluations. To develop an exclusive user interface, the PCIe-HDV62A's standard C++ DLL library is available for developers. It also features VB, .NET, C#, BCB, and MFC template programs to shorten the development schedule and supports NI's LabVIEW, Euresys' Open eVision, and OpenCV for image analysis and recognition.

Conclusion

Multimedia video is an unstoppable wave as a new generation of consumer demand for video entertainment continues to grow. When 1080p Full HD is adopted as a standard specification, multimedia video devices will have to adopt HDMI as the primary output interface. Selecting easy to learn and highly expandable industrial HDMI video data capture and testing products with enhanced standards support will help automate and expedite the HDMI testing schedule to stay ahead of competitors while still producing quality products for this dynamic market.

PCIe-HDV62A:
Dual 1-CH PCI Express® HDMI Video & Audio Capture Card(formerly HDV62A)

Related ADLINK Links:

• More about ADLINK PCIe-HDV62A
• More about ADLINK Vision Products