only write trailer when state says so, should fix issue #646
only write trailer when state says so, should fix issue #646

git-svn-id: a4d7c1866f8397a4106e0b57fc4fbf792bbdaaaf@15398 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

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