You could do it all with a regex, a bit like this...

use strict;
use warnings;

while (<DATA>) {
    print unless /[^,]+,\d+,([^.]+\.){2}[^,.]+/;
}

__DATA__
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
[download]

Output

cls3,27,Media.vdenc,media_vd
cls4,47,Media.hevc,media_vd
cls5,57,Media.ENC,media_vd
[download]

Though that is not the most readable way :)

Cheers,
R.