If a camera supports multistreaming, you can select the quality of the video stream that you want to display in the Surveillance window.

To select the video stream quality, do as follows:

  1. In the context menu of the Surveillance window, select the Select quality item.

  2. Select the quality of the video stream that you want for display in the Surveillance window.

    Menu item

    Description

    Auto (GreenStream, default)

    Algorithm for displaying a video stream in the Surveillance window if there are several streams in the camera (see Camera):

    1. a suitable video stream is selected using the following algorithm:
      1. determine the available space for video output on the layout;
      2. select the video streams for which the Use for GreenStream option is enabled (see Camera) and sort them in ascending order of the original video width;
      3. for each stream:
        • reduce the original height and width while maintaining the proportions so that the new height and width do not exceed the available space for video output on the layout;
        • if the size of the stream after inserting it into the output area does not exceed 110% of the original size, select this stream for further output.
    2. select the stream that has the highest frame rate among other suitable video streams of the same resolution;
    3. if several video streams were selected in the previous steps, select the video stream with the maximum bitrate among them.

    If a stream was selected based on the maximum bitrate, then another stream will be selected only if its bitrate is more than 5% higher than the current one (to eliminate frequent switching if the values are approximately equal).

    When changing the characteristics of video streams, the decision to change the stream to display is made only if the need for a change is confirmed within 35 seconds. This measure is also intended to eliminate frequent switching of video streams.

    When the Surveillance window is enlarged, it switches to a high-quality video stream.

    You can specify the GREEN_STREAM_SCALE_RATIO environment variable (see Appendix 9. Creating system variable), which allows you to change the resolution depending on the required video stream quality.

    • To decrease the resolution (display a video stream of lower quality), set the value of the GREEN_STREAM_SCALE_RATIO variable greater than 1. For example: 1.25, 1.5, 2, or 3.

    • To improve the resolution (display a video stream of higher quality), set the value of the GREEN_STREAM_SCALE_RATIO variable less than 1. For example: 0.75, 0.5, or 0.25.

      You must select the values of the variable empirically.

    High quality

    Algorithm for displaying a high-quality video stream in the Surveillance window if there are several streams in the camera (see Camera):

    1. select the video streams for which the Use for GreenStream option is enabled (see Camera);
    2. among the selected video streams, select those that have the highest resolution;
    3. among the selected video streams with the highest resolution, select the one with the highest frame rate;
    4. if several video streams were selected in the previous steps, select the stream with the maximum bitrate among them

    Low quality

    Algorithm for displaying a low-quality video stream in the Surveillance window if there are several streams in the camera (see Camera):

    1. select the video streams for which the Use for GreenStream option is enabled (see Camera);

    2. among the selected video streams, select those that have the lowest resolution;

    3. among the selected video streams with the lowest resolution, select the one with the highest frame rate;

    4. if several video streams were selected in the previous steps, select the stream with the minimum bitrate among them

    Other

    You can select a specific video stream from a video camera to display in the Surveillance window

  3. Click in the area between Surveillance windows.

Selection of the video stream quality in the Surveillance window is complete.