decode_mpeg: fix various bugs spotted by Bernhard Ehlers
decode_mpeg: fix various bugs spotted by Bernhard Ehlers


UIKit0/libdvbpsi,cotdp/libdvbpsi,garbear/libdvbpsi,cotdp/libdvbpsi,garbear/libdvbpsi,mwgoldsmith/dvbpsi,paraeco/libdvbpsi,mwgoldsmith/dvbpsi,garbear/libdvbpsi,avble/libdvbpsi,Boxee/libdvbpsi,vlc-mirror/libdvbpsi,krieger-od/libdvbpsi,mkrufky/libdvbpsi,vlc-mirror/libdvbpsi,avble/libdvbpsi,hiroshiyui/libdvbpsi,mwgoldsmith/dvbpsi,avble/libdvbpsi,paraeco/libdvbpsi,hiroshiyui/libdvbpsi,Boxee/libdvbpsi,mkrufky/libdvbpsi,paraeco/libdvbpsi,hiroshiyui/libdvbpsi,krieger-od/libdvbpsi,vlc-mirror/libdvbpsi,mwgoldsmith/dvbpsi,mkrufky/libdvbpsi,paraeco/libdvbpsi,UIKit0/libdvbpsi,krieger-od/libdvbpsi,UIKit0/libdvbpsi,Boxee/libdvbpsi