Second, is it legal to put the footage on YouTube? Well, if the material is 100% your own, putting the material on YouTube is definitely legal. Even if the material itself shows you committing an illegal act. But I don't think the police is going to investigate you for having an exterior camera, based on YouTube videos alone. (Although the police have investigated more serious crimes based on YouTube/Facebook videos.)
I used to think this until I posted a video on YouTube showing a shocking display of airmanship - namely the ATC between a flight instructor and the Tower. In this case, the FI and his student established themselves on a 4 mile final at an international airport, within a Class D airspace, WITHOUT even making contact with the tower.
After being contacted and cleared to land, they then bimbled down the runway with other traffic on final and upon being asked to expedite, they then BACKTRACKED down the active runway, causing another flight to be forced to go around. Then they got themselves hopelessly lost 3 times until Ground then sent them a "Follow Me", you could hear the exasperation on the radio.
I then posted this video on YouTube but was soon approached by the local government and was advised that posting extracts from Air Traffic Control was illegal in Germany and also in most European Countries, so was "requested" to remove the video or face the consequences of a prosecution under the German "Fernmeldegeheimnis" laws which prohibit (amongst others) listening in to Radio Transmissions. A successful prosecution, I was advised, would not only cost me money but could cause me to lose my licence due to the obligatory "Zuverlaessigkeitsueberpruefung" which we are regularly subjected to.....
So my tip: if it's ATC talking to YOU, you should be ok. If it's between third parties, this is a severely dark grey area.....