It looks fake. The victim was vocalizing after his mouth was covered with dirt and rocks. If it was real, we would hear choking sounds, or at least see the dirt around the victim move as his body goes into convulsions from coughing and gagging. The edit was sneaky - the last shovelful of dirt rearranged the stripes on the victims head gear, which was the natural point of reference for telling if the filmmaker swapped the "victim" with a dummy for the last ten seconds.

Another reader:

In the article you linked to, it says the man being buried "is then accused of carrying a camera to capture footage of Assad's forces to send to television networks". I'm wondering why they would do themselves what the victim was accused of doing, which was videotaping Assad's atrocities and releasing to the pubic. Doesn't make sense. Plus the voice seems dubbed in, and the jump cut, as you said, looks fishy.

Another:

I do a bit of volunteering for Syria Tracker (though do not claim to speak for them), so have seen a number of violent videos in the course of tracking human rights abuses. All videos like this must be taken seriously until definitively proven otherwise, but the video doesn't ring true to me.