Based on that video and other comments I'm guessing that it was a much higher percentage of Philly fans. Lucky for us that they picked Baltimore this year, maybe next year they won't travel as much as their team falls apart.
Watched a bit of that video clip and the Orioles supporters certainly do look outnumbered.
As it did at the Capitals, winning should drop the opposition turn-outs. The Orioles are only selling to 54.7% of capacity this season - better than last year's 48.3% but still only good for 26th in the majors (full 2012 list:
http://espn.go.com/mlb/attendance/_/sort/homePct) so naturally they'd be vulnerable to invasions. Meanwhile, the Nats attendance continues to rise (32k on a Thursday afternoon for the Mets finale with the smallest Met turn-out I've ever seen here???) - if the winning continues and becomes real playoff contention, locals will snap up more tickets (not least through growth in the STH base) and Preparation H Park at Camden Yards will be a much better option for the Philly legions.
