cls1,37,Media.vdenc.abcunit,media_vd
cls2,7,Media.Wigig.plsunit,media_vd
cls3,27,Media.vdenc,media_vd
cls4,47,Media.hevc,media_vd
cls5,57,Media.ENC,media_vd


##</code><code>##

#!usr/bin/perl

my $file = $ARGV[0] or die "Please provide csv file \n";

open(my $data , '<', $file ) or die "Cannot open csv file $!\n";

while (my $line = <$data>){
	chomp $line;
my @col = split ",",  $line;
push (my @cluster, $col[2]);

  foreach my $field (@cluster){
	  my @cls = split ".", $field;
	  print @cls;
  }
}

##</code><code>##

Output should be :
cls3,27,Media.vdenc,media_vd
cls4,47,Media.hevc,media_vd
cls5,57,Media.ENC,media_vd