NI 5431 Composite Video Generator
Creating Insertion Test Signals Using YUV Mode

Create YUV Color Sweep Insertion Test Signal shows you how to create an ITS data file based on YQI/YUV data. Some test patterns are easier to create using the two chroma components (Q and I for NTSC, or U and V for PAL) than using an RGB approach. In other cases, you simply cannot create the test signal using RGB signals.

This example VI creates a color sweep test pattern and saves the data as a file calledtest create YUV ITS.its. The file can then be recalled using Intermediate Insert ITS in Composite Signal.

You can access this example VI by selecting Functions»Video Generation»Generator Examples»Create YUV Color sweep Insertion Test Signal.

To generate and save a color sweep test pattern, complete the following steps:

1. Launch the example VI.
2. On the front panel, use the operator tool and the up and down arrows on the Video type control to select the appropriate video format.
3. Verify that the module ID control value matches the value assigned by MAX during configuration of the module.

Note  This VI has predefined parameters for demonstration purposes. If you have not installed the software in theC:drive root directory, correct the file path of the ITS signal to be saved on the front panel so that it matches the installation.

4. Run the VI. The YUV Insertion Test Signal appears in the front panel and the ITS data are saved on the disk.

A YQI/YUV ITS is defined as three data arrays (Y, Q, and I for NTSC; Y, U, and V for PAL; or Y, Db, and Dr for SECAM) of 16-bit data. The luma Y signal is represented by a 16-bit unsigned array (U16) while the chroma components (Q and I or U and V) are represented by 16-bit signed arrays (I16). The size of the arrays depends on the selected video format and the specified active video duration, which you can modify using the Image duration (µs) attribute. The default value for an NTSC signal is 52.2 µs, corresponding to approximately 1,044 samples at the nominal sampling frequency of 20.013 MHz. For B-PAL or SECAM, the default active video duration is 52.0 µs, corresponding to 1,040 samples at the nominal sampling frequency of 20.000 MHz. Refer to Attribute List for more information.

The default size of the array is 1,044 for M-NTSC and 1,040 for 50 Hz-type PAL or SECAM. For the luma signal Y, the data is scaled so that zero corresponds to black or 0 IRE (if no setup is applied), and 65,535 (the maximum value for unsigned 16-bit data) corresponds to white or 100 IRE. For the chroma component signals, the data is scaled so that ±50 IRE corresponds to ±32,767 (the maximum and minimum values for signed 16-bit data).

Note  For SECAM users, the terminology used in this example VI is based on the PAL chroma components U and V. However, these components are internally scaled so that they correspond to the usual Db and Dr components when a SECAM image generates.

The scaling factors used internally are in order as follows:

Db = 1.505 * (Eb - Ey) = +3.0527 * U

Dr = -1.902 * (Er - Ey) = -2.1688 * V

Also, because a modulation is always present in SECAM, even if the U and V components are set to zeros, an option for generation of the Y component only (without the FM subcarrier) is available on the front panel. Enable Kill Chroma Modulation if you do not want the FM subcarrier signal to generate on the test signal.