how to save pcap file after extracting groud plane

Hello,

I extracted ground data using 'segmentGroundFromLidarData(ptCloud)' form 3D lidar (Velodyne) data. How to save ground segmented data as a pcap file to use for the further process?

I tried to save using as below but it is not working out.

  save('pointCloudTest.mat','ptCloud') 
  save GroudData.pcap groundPtsIdx 

Please find the code:

  veloReader = velodyneFileReader('lidar.pcap','VLP16');
  for i = 1 : 597 
         % Read current frame.
         ptCloud = veloReader.readFrame(i); 
         
         % Create label array.
         colorLabels = zeros(size(ptCloud.Location,1),size(ptCloud.Location,2)); 
 
         % Find the ground points.
         groundPtsIdx = segmentGroundFromLidarData(ptCloud);
 
         % Map color ground points to green.
         colorLabels(groundPtsIdx (:)) = greenIdx;
         
         % Map color nonground points to red.
         colorLabels(~groundPtsIdx (:)) = redIdx;
         %save('pointCloudTest.mat','ptCloud') 
         %save GroudData.pcap groundPtsIdx 
         view(player,ptCloud.Location,colorLabels)
     end