Parking in the Japantown area or the lower pacific heights neighborhood (around octavia/laguna) then walking to the fillmore (10 to 15 minute walk) may be your best option. There's also a few parking garages in Japantown (not sure of the rates though) that may be another good option to explore. But in my opinion, if you don't need to drive, then just take an uber or a lyft.
The parking garages in Japantown or up thr hill from the theater on Fillmore
Outside street parking is in a busy and safe area
I parked along the street and was perfectly fine. Just have to grab an open spot.
Thanks! Your answer is awaiting moderation.