This is a video on "The Great Vows of Avalokiteshvara Bodhisattva and Maha Karuna Dharani (Great Compassion Mantra - 大悲咒)". It's sung by Chyi (Qi Yu - 齊豫). Qi Yu is a singer who also popular for singing Buddhist songs. In fact, when you type a Buddhist keyword in Mandarin, you may probably find a video of her singing Buddhist song. She has her style in singing Buddhist song, quite different from others.
This video consists of two parts with Avalokiteshvara Bodhisattva's images. The first part is "The Great Vows of Avalokiteshvara Bodhisattva (觀世音菩薩發願文), and the second part is Maha Karuna Dharani (大悲咒).