Resolve the cropping offset of the conference camera VGA signal input

Resolve the cropping offset of the conference camera VGA signal input

About the situation where the camera VGA signal is input to other terminal equipments, such as being cropped, offset, or black border, related to the term “line-field synchronization”, and the VGA signal can generally be described as R, G, B, H, V, five. The signals, respectively, transmit red, green, blue, line signals, field signals, wherein the line field signals are used to ensure that the signal receiving display device can maintain the same frequency as the signal transmission end, thereby correctly reproducing the image.

What is a line synchronization signal

In order to synchronize the line scanning and field scanning rules of the receiving end, the television signal sending end sends a pulse signal to the receiver after the line (field) scanning is normally completed, indicating that this line /H (field/V) has ended, this pulse The signal is a line (field) synchronization signal.

When the VGA output of the conference camera is connected to the computer monitor, some resolutions may not be synchronized and the screen size may be abnormal. However, most of the functions of the screen can be automatically adjusted through the monitor. If the back-end VGA The signal receiving end does not have an automatic adjustment function, and it may not be able to correctly reproduce the image at certain resolutions because the input line and field signals are not synchronized with the output frequency of the display device, and the main performance is as shown in the figure.

When this problem is encountered, the resolution can be switched first. If the problem is solved, if the problem is solved, if it is still invalid after the switching, you need to modify the program to adjust the line and field signals of the camera.