When i was a child in Instanbul, this chant was sung from the neighborhood mosque to announce a death in the community. It was a signal to become still and offer a prayer for the departing soul. I have always loved its peace.
For the misunderstand .. That is not the Azan which is the call for the prayer to Allah .. That is a prayer for the Prophet .. "Alsalatu waassalmualik ya Rasula Allah" literally mean Allah's prayer and peace upon you Prophet Mohammed (SAW)
Thank you