BWC video indicates Mark Gaskill was holding his phone as police shouted "gun"

The Rochester Police Department shot and killed 28-year-old Mark Gaskill of Rochester early Friday morning.  According to the RPD, the ShotSpotter alarm went off in the general area, indicating that a gun may have been shot.  The RPD then pulled over a car with Gaskill in the backseat and began questioning the driver and front passenger.  Both stated that they were driving to the hospital because the driver was pregnant and experiencing pains.  After about 15 minutes, one of the officers asked to open the back door to talk with Gaskill who had been on his cell phone for most of the stop.  As the officer opened the door, he suddenly shouted "there's a gun", at which point the officers fired at least 9 times at the car.  Gaskill was pronounced dead on the scene.
 
After the shooting, the RPD claimed that Gaskill was "brandishing" a handgun, but it's unclear what that means.  Are they saying that he was he holding the gun or that a gun was visible in the car?  It's extremely unlikely that he was pointing the gun at anyone since the RPD has not specifically said that.
 
The police released body worn camera footage from the incident during the weekend.  The BWC footage does not conclusively tell the story of what happened inside the car, however an analysis of the video seems to indicate that Gaskill was still holding his cell phone when the officers began yelling "gun".  Presented below are still frames from the video WROC posted to YouTube.
 
Just before the fatal shooting, Gaskill can cleary be seen holding his phone.  At this point one of the officers can be heard saying, "You good if I open this door to talk to you?" (timecode 24:33:09).

 
At that point, the camera shakes as the officer moves to open the door.  The next frames that show Gaskill are blurry and difficult to see, but position of his hands appears very similar to how you would hold a phone.  Also, the object in his hand certainly seems phone-shaped.  It's not clear from these images if one or two hands are holding the object, but when viewed frame-by-frame it certainly seems like two hands.  The officer begins shouting "gun" right when these images were captured (timecodes 24:54:81 and 24:54:85)
 

View video frame-by-frame

After this point, the camera goes shakey again as the officer runs for cover as other officers open fire and kill Gaskill.  At the end of the footage, one officer goes into the car with evidence gloves on, presumably to retrieve a gun, although I couldn't see what they took out when watching the video.

I'd like to note again that the footage is difficult to intepret and the video quality is not ideal -- especially since it has been re-encoded for YouTube.  Rochester Indymedia has made a FOIL request to the City of Rochester for a copy of the original file.