Mplayer doesn't stream from stdin without cache setting

I just noticed that mplayer no longer wants to stream from stdin when I unrared my files straigth to mplayer using

unrar p -inul some_multipart.rar | mplayer -

like I’ve often done before, giving me errors like this instead:

Cannot seek backward in linear streams!
Seek failed

This behaviour has probably existed for a while, however I haven’t noticed it before since I’ve actually been using a workaround for this anyways. To play streams from stdin, a quick fix is to set cache size manually. E.g. like this:

unrar p -inul some_multipart.rar | mplayer - -cache 8092

Cache size can be set to whatever you like it to it seems, so feel free to customize it to your own preferences and bandwith.