VideoWriter

Prerequisites:

  • bonsai Vision Library

Category: Sink

Brief: Writes the input image sequence to a compressed .avi file

Input (OpenCV.Net.IpIImage) - 2D matrix of pixels, such as that produced by CameraCapture or the Image output of other camera source nodes

Properties:

  • Buffered (bool) - indicates whether writing should be buffered
  • FileName (string) - name of the output file or full path to the output file if the desired path is different from the current working directory
  • FourCC (string) - the four-character code of the codec used to compress video frames, e.g. FMP4
  • FrameRate (double) - playback frame rate of the image sequence
  • FrameSize (OpenCV.Net.Size) - frame size in the output file
    • Width (int)
    • Height (int)
  • Overwrite (bool) - indicates whether the output file should be overwritten if it already exists
  • ResizeInterpolation (OpenCV.Net.SubPixelInterpolation) - interpolation method used to resize video frames, e.g. NearestNeighbor
  • Suffix (Bonsai.IO.PathSuffix) - optional suffix used to generate file names: None, FileCount, Timestamp; generates new files even if Overwrite is set to True

Output (OpenCV.Net.IpIImage):

  • IsInvalid (bool)
  • ElementType (int)
  • Size (OpenCV.Net.Size)
    • Width (int)
    • Height (int)
  • Depth (OpenCV.Net.IpIDepth)
  • Channels (int)
  • Width (int)
  • Height (int)
  • WidthStep (int)
  • ImageData (System.IntPtr)
  • ChannelOfInterest (int)
  • RegionOfInterest (OpenCV.Net.Rect)
    • X (int)
    • Y (int)
    • Width (int)
    • Height (int)
  • IsClosed (bool)
tip

How to get real-time playback rate? Without a hardware trigger, the acquisition frame rate might be unstable. If the playback seems vastly different from real-time, one can place TimeInterval after VideoWriter to measure the real frame rate and then specify the corresponding frequency in the FrameRate property of VideoWriter.

With a hardware trigger, one can set the FrameRate property of VideoWriter equal to the (known) trigger frequency.

caution

Runtime Error: A valid file path must be specified

Occurs when the FileName property is left empty or not specified properly.

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