Reuters
I think I know the video you mean. I saw several on Reuters this morning, and it might be this one:
http://www.reuters.com/video/2014/07/17/amateur-video-shows-smoke-billowing-from?videoId=324263506&videoChannel=1&channelName=Top+News
I have it paused on a frame in which four streaks are visible. Letting it run, it's clear that this is dropping debris trailing smoke, and not rocket plumes.
It's unlikely that plane came down by accident in that location at that time. Somebody fired one or more rockets at it, but currently Ukrainians and Russians are pointing the finger at each other. Good forensic work by somebody like the NTSB will eventually prove whose finger is telling the truth.