Based on the noise, I also assume that the compressor is installed in the indoor unit. The air conditioner is much quieter than monobloc units but slightly louder than other split units I have heard.
The refrigerant is pumped outside to dissipate the heat. Everything has advantages and disadvantages: The outdoor unit is extremely quiet in this model. Complaints from neighbours are therefore almost impossible. What also convinces me about this model: The indoor unit is very slim and has a place in our house where a classic split unit would be too deep/thick.

The compressor of a split air conditioner should always be mounted outside, as the heat exchange takes place in the compressor and this part must not be placed in a room.