Get the figure handle from the player object produced by pcplayer.
Use VideoWriter to create a VideoWriter object and use getframe to write the figure frame on each iteration to the video.
v = VideoWriter("myvideo.avi");
cleanupVideo = @()close(v);
open(v)
player = pcplayer([0 1],[0 1],[0 1]);
fig = ancestor(player.Axes,'figure');
for i = 1:100 % <-------------here's your update loop
if ~isOpen(player)
continue
end
ptCloud = pointCloud(rand(1000,3,"single"));
view(player,ptCloud);
frame = getframe(fig);
writeVideo(v,frame)
end
clear('cleanupVideo') % not needed if this is in a function
