Move RV3/4 frame type check upper, so 1-slice unanchored B-frames are checked too
Move RV3/4 frame type check upper, so 1-slice unanchored B-frames are checked too

git-svn-id: a4d7c1866f8397a4106e0b57fc4fbf792bbdaaaf@17031 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg,prajnashi/ffmpeg