It is not obligatory to offer expiation for watching movies, rather it is obligatory only to repent sincerely

What you have to do is to repent sincerely to Allaah, by
regretting this sin, giving it up and resolving not to return to it. You
should also pray a lot for forgiveness, and do a lot of righteous deeds,
because Allaah says (interpretation of the meaning): 

“Verily, the good deeds remove the evil deeds (i.e. small
sins)”

[Hood 11:114]

This is what will expiate
for your sin of looking at and listening to haraam things. With regard to
those who say that you have to offer expiation – such as the example you
mentioned – for watching movies, he has to produce evidence for that,
because it is not permissible to impose something upon the people without
sound evidence. Whoever imposes something on people that was not enjoined by
Allaah has ordained something in the religion for which Allaah has not given
leave. It is not permissible to invent expiations for sins and to specify
their type and number without evidence from sharee’ah. 

Fasting in general terms, without specifying a particular
number of days, comes under the heading of good deeds which wipe out evil
actions. May Allaah help us and you to repent sincerely..