Barack Obama's speech at the Democratic National Convention pulled in a bigger US TV audience than the Beijing Olympics opening ceremony, this year's American Idol final and Oscars coverage.

Latest Nielsen ratings figures show that Thursday night's speech, in which Obama accepted the Democrat presidential nomination, pulled in a total of 38.4 million viewers in the key 10pm hour across various channels that covered the event live.

Cable network CNN was the best performing of any of the channels covering it, beating the main broadcast networks.

By comparison, last month's Olympics opening ceremony attracted 34.2 million, the American Idol final in May pulled in 21.7 million and the February Oscars broadcast to 31.6 million.