Nissan Primera P12 - Engine sound when on idle

Sounds exactly like the noise mine made when the exhaust front mount broke. The exhaust was just about tapping on the crossmember under the front. Local exhaust place welded it for ten quid. Grab the exhaust (when it's cold) and see if it rattles about.

Yesterday i was at the mecanic and said that if it was a bearing the sound should be present alawys and not intermitent as mine. First he was thinking that the noise is hearing from EGR, he disassembled and cleaned it out (it was very dirty), and with this occasion it resolved my other problem with hessitation (thoug i still sensed last night only once a little hesitation in third gear at 3200 RPM, but only once after all the testing on the road ) and now it runs a lot better still need to test it this days to see if the hessitation completely dissapeard. So after all the testing with the mecanic in the car and with tester conected as we stopped at his workshop i said to him to accelerate as i did in the video and the noise still could be heard but this time very little and between 1200 - 1000 RPM as it dropped. I popped the hood and said to him that the noise when i was first heard it was from the left side of the engine drom alternator area, and he said someting about " that someting from rotor of the alternator or something it slips " and this is the cause of this. I would have to go back to him to check that out because he didn't have the time yesterday. After i left from him i drove about 20 km and stopped the car then i rev the car as before and the sound appeard again as show in video. Honestly iot drives me crazy, i rezolve one problem and then another appears :)))) so i will take your advices into consideration and try to shoot from engine area but i don't thing it will hear the sound much better (i'm filming with a iphone 4s).
I will come back and tell you what i discovered. THX :D

@p11primeragt, i made a video of the top of the engine from camsaft, to me it look like its getting oil, it is good ? (link below) As for the sound i didn't hear it from last night when i was testing the car for hessitation and today aswell i start the car almost 10 times and tried to reporduce the sound and its gone for now. If it will appear again i will take a recording from engine area and try the metode with the screwdriver.

https://www.youtube.com/watch?v=xdcYXBetuzk&feature=youtu.be  

I looked with the engine OFF, after i did the earth fix to the both of the rear headlights, so after 40 min - 1 hour but the engine wasn't warmed up, from home to the place where i did the earth fix i maked 800 m. I don't think that is the blets or bearing issue because i didn't hear the sound from last night and today. We'll see if it will show itself again these days, hope not :))

You will need to pull and push on various points of the exhaust to see if you can hear it hitting something.
The sound also reminds me of a drive belt dancing on the overrun, again pull and push on the alternator and the a/c compressor to see if there is any movement caused by a broken bracket or loose bolts.
A stretched belt will also dance on the overrun.