VideoMASTER Getting Started Guide

NI VideoMASTER is a suite of video test solutions that covers a wide variety of video standards and formats for both analog and digital video generation and acquisition.  NI VideoMASTER offers various solutions for analog and digital video generation and acquisition. 

This getting started tutorial will focus on configuring the NI VideoMASTER solutions for analog video acquisition and analysis using the interactive step types in NI TestStand. This guide can also be used to learn how to use the NI VideoMASTER soft front panel (standalone executable) which is very similar to the NI TestStand step types. Not discussed in this tutorial is the programming of NI VideoMASTER using the LabVIEW API (or driver) to program video measurements.

One example of an automated test solution would be performing functional tests on a set top box.  Dozens of tests on a signal need to be evaluated to ensure the system meets internal and industry standards.  If done manually, these tests could take several minutes or hours along with the potential of human error involved.  Instead of manually performing each measurement and validating it meets specifications, a VideoMASTER Setup step could be used.  The measurement could be taken, compared to a given set of criteria, and a pass/fail for the system can be done in a matter of seconds.

In this tutorial we will go through the steps needed to develop an automated test solution using NI VideoMASTER.

Using NI VideoMASTER in TestStand

Introduction to TestStand

NI TestStand is a test management software designed for the development of automated test applications. Using NI TestStand, you can develop test sequences that integrate code modules written in any test programming language. These sequences also specify execution flow, reporting, database logging, and connectivity to other enterprise systems. You can deploy test programs with user defined operator interfaces..  Using the NI VideoMASTER steps for NI TestStand you can interactively configure your measurements and define pass/fail limit criteria in order to perform various tests on video signals.

To start a video test application in NI TestStand launch the NI TestStand Sequence Editor (Start >> Programs >> National Instruments >> TestStand >> Sequence Editor) and find the microLEX folder in the Insertion Palette on the left side of the screen.  Depending on what is installed, you will see a variety of subfolders for VideoMASTER, VideoMASTER Generation, Digital VideoMASTER, and Digital VideoMASTER Generation.

Fig 1) Left -  The VideoMASTER setup step in TestStand can be found in the microLEX folder of the Insertion Palette. Drag and drop the VideoMASTER Setup step into your program to start configuring video tests

We will now configure our system to acquire the analog video signal we want to test.  To start an application, simply right click on the “Insert Step Here” dialog in the sequence editor and go to Insert Step >> microLEX >> VideoMASTER >> VM Action >> VideoMASTER Setup.  Another option is to drag a VideoMASTER Setup step from the VideoMASTER folder onto the sequence editor.  *You will insert a new step for every measurement (colorbar, frequency sweep, multiburst, etc…)*.  The VideoMASTER Setup step can be renamed to match the measurement it will make by left clicking the title.  To launch the VideoMASTER User Interface, right click the step and go to Edit VideoMASTER. *This may take a few moments to load the first time. The VideoMASTER Setup step is now ready to be configured for acquisition and performing measurements of the video signal. Tip: If taking several measurements using similar configurations, you can also copy and paste steps within TestStand.  By copying and pasting a previously configured NI VideoMASTER step you will reduce the number of configuration changes that need to be made.

The left side of the user interface contains five different tab controls that allow you to configure various parts of your automated test application.  These tabs include: File Control, Measurement Control, Filters Control, Test Sequencer Control, and Acquire/Instrument Hardware Control.

Fig 4) The Controls section of the VideoMASTER User Interface consists of five controls: File Control, Measurement Control, Filters Control, Test Sequencer Control, and Acquire/Instrument Hardware Control.  These five controls contain all the necessary features to manually test the video signal and take measurements, and also to configure the steps for an automated application.

File Control  – The File Control tab gives you the ability to load previously acquired waveforms and also allows you to save the current waveform to file for offline analysis.

Measurements Control  – The Measurements  Control is used to configure settings for the measurement to be made (colorbar, multiburst, etc…).  The Measurements Control will be covered extensively in the Performing Measurements section.  This section will be uniquely configured for the given measurement desired in each VideoMASTER Setup step.

Filters Control  – The Filters Control provides the ability to set software filters on the video signal.  Filter classes include: Butterworth, Chebyshev, Inverted Chebyshev, Bessel, Elliptic and FIR.  Filtering is activated by selecting a Filter Type different than “None” on the Filter Control.

Test Sequencer Control  – The Test Sequencer Control defines what information flows between NI TestStand and the VideoMASTER Setup step.  Depending on your measurement, you may want to send different information to NI TestStand.  For example, one test may require the whole waveform to be sent to NI TestStand for reporting purposes, but for most you will probably only pass the specific measurement values. 

Another component of the Test Sequencer Control is the ability to force initialization, acquisition, and closing the hardware connections.  For an application that performs multiple measurements you will only need to initialize your hardware on the first measurement, rather than on each measurement.  The Test Sequencer Control allows you to Force Initialization, Force Acquisition, and Force Close the connection to the hardware in each VideoMASTER Setup step.  More information on the Test Sequencer Control will be covered in the Setting Up an Acquisition section.

Acquire/Instrument Hardware Control  – When preparing an application to acquire the video signal, the hardware settings need to be configured for acquiring the video signal.  Settings such as sample rate, video signal type (NTSC, PAL, etc…), input channels, number of lines to read, etc…are configured in the Acquire/Instrument Hardware Conrol.  These settings ensure the VideoMASTER Setup Step configures the hardware correctly.  The Acquire/Instrument Hardware Control will be covered more extensively in the next section.

Setting Up an Acquisition

 

Fig 5) The Configure button launches a window (right) that shows how the hardware is configured for the acquisition and which channels have an active signal connected.

On the Acquire/Instrument Hardware Control you will find the Configure and Initialize buttons.  Click the Configure button to launch the Configuration window so you can choose the hardware used for the acquisition. It also indicates which channels have active video signals connected.  Clicking the Initialize button launches a window that allows you to initialize the Analog and/or Digital VideoMASTER hardware.  After the OK button is pressed, the Initialization window opens and explains how all the hardware is initialized.  Once the hardware is initialized, the Acquire Once and Acquire Continuously buttons will no longer be grayed out in the Acquire/Instrument Hardware Control.

The Acquire Once button will take a single acquisition of the video signal and update the Waveform graph in the VideoMASTER Setup User Interface.  Go to the Picture tab and click Refresh and the video display that was captured will be displayed.  The Results tab will contain the results of the measurement taken.  Taking measurements will be covered in the next section so this tab will be empty until a measurement is configured.

 

Fig 6) The Waveform and Picture tabs display the video signal acquired.

Automating the Initialization and Acquisition Steps

The configuration and initialization steps can be run manually by pressing the buttons, which is ideal during development and debug of the application to ensure that the VideoMASTER Setup step is configured properly.  During the automated test this is done programmatically through the Test Sequencer Control when running the TestStand sequence.  Initialization should be configured for the first VideoMASTER Setup step in an application and also for any steps that require a change to the signal types (NTSC, PAL, YUV (Component), etc…).  By default, the driver will execute an acquisition for each VideoMASTER Setup step, but if the acquired video signal from the previous step is valid for the current measurement step, the Force Acquisition should be unchecked to improve test execution time.  By initializing and acquiring only when needed, you will significantly reduce the test execution time of your application.  For more information on when to force actions, see the VideoMASTER help by clicking the “?” on the top right hand side of the screen.  The force actions will be under VideoMASTER Sequence Interface  >> Controls and Indicators >> Initialization and Acquisition.

Fig 7) The Test Sequencer Control provides the ability to Force Acquisition, Force Initialization, and Force Closing of the hardware connections (Left).  This is extremely beneficial for automated test sequences that contain tens or hundreds of measurements (Right).   Tens or hundreds of measurements can be performed in a matter of a seconds, making VideoMASTER an ideal solution for automated video test applications.

Taking Measurements

*In order to configure a measurement, there must be a video signal acquired or loaded from file. 

The measurements are configured in the  Measurements Control tab.  The two main parts of the Measurements Control are the Locations File and the Measurement Group.

The Locations File contains information on where in the signal, in time, the measurement should be taken.  A Locations File is created for each different video standard (NTSC, PAL, YUV (Component), etc).  For example, the location in the signal that a color bar measurement will be performed on an NTSC signal will be different than the location of the measurement on a PAL signal, so these would have different Locations Files.  Several Locations Files are included with VideoMASTER for common test patterns and video standards, but you can create user defined Location Files for custom test patterns that fit your specific test requirements. 

First select the Locations File to be used by pressing the Select Locations button and choosing the Locations File corresponding to the video standard to be measured.  Next, ensure that the Locations File configuration complies with the video waveform being measured.  Click the Edit Locations button to launch the Measurement Locations Editor window.  *If the Edit Locations button is grayed out, it means no signal has been acquired yet and an acquisition is needed.

Fig 8) For the ColorBar Measurement, the three locations that must be set are the where the white starts, where the color starts, and where the color ends.  These can be chosen by moving the cursor on the graph to that location of the signal.

At the bottom of the Measurement Locations Editor there is a tab for each measured test element in the video signal (Color Bars, Color Multiburst, Bar, etc…).  Information on making edits to each of these locations can be found in the VideoMASTER Help Document under User Interface >> Measurement Locations Editor, under VideoMASTER Data Files >> Measurement Locations and also under Video Measurements.  Once the locations have been verified, press the Close button to exit the Edit Locations window. 

The measurement can be tested manually by clicking the Measure Once button on the Measurements Control.  The Results tab will then populate for the measurement specified.  The information from the Measurement Results section of the Results tab is also passed to TestStand where it can then be evaluated to see if the system meets requirements.

Fig 9) The Results tab contains all the relevant results from the measurement performed on the video signal.

Generating Pass/Fail Tests with the Limit Editor

In order for a video test system to pass the automated test sequence, the individual tests must be compared to company or industry standards and requirements.  This is accomplished for each measurement using the Limit Editor.

To launch the Limit Editor, click on the VideoMASTER Setup step in the sequence editor of TestStand.  At the bottom of the screen you will see an Edit Limits button.  This will launch the Limits Editor and allow you to change limits for that test.  Another option is to right click on the VideoMASTER Setup step and go to Edit Limits.

Fig 10) The Limits Editor is launched from the TestStand sequence editor and is used to compare the VideoMASTER measurement results with internal requirements or industry standards.

The scroll bar on the left side of the window scrolls through all the measurement results that can be evaluated.  The Minimum Limit and Maximum Limit columns can be edited to ensure the measurements meet requirements. 

The defined set of limits will be saved with the NI TestSTand sequence file.  However, the limits can also be saved to file and then reused in other test applications.  For example a company may define its limits for general types of products.  When developing a new test application, you can load the limits from a file that already exists.  The Limit Editor also has the ability to dynamically load limits, allowing you to dynamically load limits from file.

Developing an Automated Video Test Application

Developing an automated video test application combines the previous sections into a single application.  For this example, an application will be set up to automate the testing of an NTSC signal that has a test matrix that consists of a colorbar (test lines 0-130) and a multiburst signal (test lines 131-261).

Fig 11) The test matrix being generated can contain several patterns that need to be measured against internal and industry standards

In this example, there are two test patterns that will be measured and tested. The first part is to insert two VideoMASTER Setup Steps into the TestStand Sequence Editor.  These can renamed to Colorbar and Multiburst to fit the measurement they will perform.

Next, the first VideoMASTER Setup Step (Colorbar) User Interface should be opened and configured for the measurement and the hardware should be initialized.  Open the VideoMASTER User interface for the first measurement and go to the Acquire/Instrument Hardware Control.  Choose NTSC for the signal type and Port 1 for the signal (the signal is connected to Channel 0 of the digitizer), then click the Initialize button and choose ANALOGUE – including Digitizer…  Since this is the first measurement being made, the hardware must be programmatically initialized, so the Force Initialise and Force Acquire boxes on the Test Sequencer Control must now be checked.

Now that the hardware is configured and a signal has been acquired the measurement can be configured.  *Note, you must manually acquire the signal once to set up the Measurement Control.  Go to the Measurements Control and select the NTSC –TPG Locations File since this is an NTSC signal.  Enter the line number that will be measured below the Waveform Graph (any line from 21-131 will work).  Choose the Color Bar measurement, and click Edit Locations to verify the locations file is configured correctly.  Click the Colour Bars tab and go through the Update from Curser list to ensure that the locations for start white, start of color, and end of color are correct.  When finished, click Close.  Click OK to exit the ColorBar measurement step.

The next step is to configure the Multiburst measurement step.  Open the VideoMASTER User Interface for the Multiburst measurement step.  Since the hardware was initialized in the first step, you can uncheck the Force Initialize and Force Acquire boxes on the Test Sequencer Control.  Go to the Measurements Control to choose the Multiburst measurement setting and choose the measurement line (any line 131-262 will work).  After taking another manual acquisition of the signal go to click on Edit Locations and ensure that each section of the Update from Curser list is correctly configured.  When finished, click Close.  Click OK to exit the Multiburst measurement step.

In TestStand, open the Limits Editor for Colorbar measurement step and make the lower limit for the White Luminance Amplitude 700mV and the upper amplitude 800mV.  Click OK to exit the Limits Editor.  Open the Limits Editor for the Multiburst measurement step and change the Burst 1 Amplitude lower limit to 400mV and the upper limit to 420mV.  Click OK to exit the Limits Editor.

Fig 12) The Run UUTs button will run the automated video test application.

Click on Run UUTs in the TestStand menu and the automated test will run and show whether the system passed or failed within seconds.  A report is also generated of all the measurements taken and which tests passed or failed.

The ability to quickly configure a set of tests to evaluate the quality of a video signal combined with the ease of automation of NI VideoMASTER is making video test much easier for engineers throughout the industry.  The combination of faster test times with faster development times makes NI VideoMASTER a powerful solution for video test.

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