Crash was introduced in 3e73ad2a8ab6d5e50ea80025d364edbe7ead1d1b (subsdelay filter) and
occurs when user or init methods set subsdelay to 0.
(cherry picked from commit fd9f59ec7cbda944c729118302c7434e5696896a)
Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>