Whining sound while driving

Did I get something wrong?There is a humming sound in the car while driving. It is very obvious when the speed is 50km/h, and it can also be heard at other speeds. It does not seem to be related to the accelerator. I took a video.

 

This is a used car. I don't know what the previous owner did. I have adjusted the toe and lubricated the brake caliper guide and piston. I suspect the sound comes from a bearing. I wonder if this sound is normal?
The whining sound is actually more obvious than in the video

 

There seems to be no change in pitch, no pitch change like do fa, only a change in volume. Sound volume is related to speed. It is most obvious at 53km/h. Above or below this speed, the noise will be attenuated. The noise has nothing to do with the throttle. When accelerating or decelerating at the same speed, the frequency of the noise will not change. I even suspected that the noise was caused by gear meshing in the gearbox. Paradoxically, neither RPM nor vehicle speed can affect the frequency of the noise. If it is wheel bearing noise, does its frequency change with vehicle speed?

 

Yes, the tires are worn. The first two have been used for about two years and have a mileage of about 20Kkm. The rear two have not even been replaced. I don’t know the mileage. The tread wear is close to the life indicator bar. Even if there is no eccentric wear, it has become It's very hard, maybe that's a problem with it。