Sounds normal but it got your attention for some reason, maybe it didn’t hiss before and you just noticed it? Could be a bad brake booster, I had one go out on a truck of mine, it’s not common but it does happen.

The system is under vacuum so there is normally going to be a little noise when the pedal is moved up or down (while car running), normal sounding like your video. However a hissing noise likely means a vacuum leak, I didn’t hear that in your video. I would start the car (so the engine creates a vacuum), then press down the break pedal and hold it down… if there is a constant hissing sound while the pedal is depressed/held down then that is likely a leaky seal or diaphragm, both part of the break booster (bad break booster). The whole system is under vacuum, when depressing the pedal, the opposite end of the pedal pushes on a diaphragm inside the brake booster.

Your video of your car’s pedal makes the normal sound while pressed in and released although I would take another video and post it again and have someone look at the car just to be safe because a lot of noise could be the start of a vacuum me leak.