Interlace video with fast movement may display double images.

Issue

Interlace video with fast movement may display double images.

Product Line

Pelco Cameras

Environment

  • DVR's
  • Analog Cameras

Cause

Double images displaying when viewing video.

Resolution

Most digital video recorders (DVR’s) process video signals by using the progressive scan output from a camera. Analog cameras output either progressive scan or interlace scan video. If the video from a camera that is received into a DVR is interlace, or if the frame of the progressive scan is not the same as what the recorder is set up for, the video may look jagged on the edges. Video with fast movement may display what looks like double images.

The progressive frame is either an odd or even frame and, when matched, will give a clearer picture. Some cameras such as the Spectra IV 35x, have the option to change the even or odd frame in the progressive mode. The Spectra-Mini IP, IP110 and IP3701, do not have the option.

Some DVR’s may also have the ability to change the even or odd frames. If neither the camera nor DVR has the ability to change to an even or odd frame, there is very little that can be performed to solve the jagged image issue. If this issue occurs, check to see if the camera, or the DVR, can be adjusted to match the even or odd frame. Changing the monitor or DVR resolution will sometimes change the frame scan, which may improve video.

Source: TT091009SP