Aug. 13 (Bloomberg) -- The broadcast of the Beijing Olympics opening ceremony used computer-generated fireworks, including a fake shake to simulate helicopter filming, because of the city's hazy skies, Chinese officials said.

General Electric Co.'s NBC, which spent $894 million for broadcast rights, used some of the fake footage, MSNBC reported on its Web site. About 2.3 billion television viewers watched the Aug. 8 opening ceremony, said MindShare, a unit of WPP Plc.

``People feel like they eat a great meal and later on you tell them there was a fly in it,'' Xiao Qiang, director of the China Internet Project and an adjunct professor at the University of California at Berkeley, said in a telephone interview yesterday.

Minutes before the ceremony, directors replaced a 7-year- old singer with an older girl considered prettier, musical director Chen Qigang told Beijing Radio on Aug. 10.

``The reason was for the nation's interest,'' Chen said in the interview. ``The child on camera should be flawless in image, internal feelings, and expression.''

The incidents add to the controversies in an Olympiad that China says is its coming-out party on the world stage. Foreign media have prodded Olympic organizers about the haze sitting over the capital and restrictions on accessing Web sites related to Tibet and China's human rights record.

Real and Fake

Shortly after the ceremony started, broadcasters used previously recorded footage of footprint-shaped fireworks running south to north over Beijing, said Wang Wei, vice president of the Beijing Olympic organizing committee.

The fireworks were launched for those attending the ceremony, yet those appearing on TV screens were different.

``On the day of the ceremony, there were actual footprint fireworks from the south to the north of the city,'' Wei said at a news conference in Beijing yesterday. ``However, because of the poor visibility, some of the previously recorded footage may have been used.''

The practice was similar to ``other big events,'' Wang said, without being more specific.

Greg Hughes, a spokesman for NBC Sports in New York, wrote in an e-mail that hosts Matt Lauer and Bob Costas discussed the matter during the broadcast. The ceremony was overseen by film director Zhang Yimou.

`Cinematic Device'

``You're looking at a cinematic device employed by Zhang Yimou here. This is actually almost animation. A footstep a second, 29 in all, to signify the 29 Olympiads,'' Lauer said, according to a transcript Hughes provided.

Costas replied: ``We said earlier that aspects of this opening ceremony are almost like cinema in real time. Well this is quite literally cinematic.''

China spent $17 billion to improve air quality during the games. The government has restricted cars to driving on alternate days, closed construction sites and ordered polluting factories to cut production or shut down.

The state-owned Beijing Times reported Aug. 9 that the 29 footprints were mostly produced digitally. The actual fireworks were difficult to film for reasons including air traffic restrictions, the paper said, citing Gao Xiaolong, who worked on the ceremony's visual effects.

The 55 seconds of broadcast footage were created during the course of a year by using weather information to recreate the nighttime haze, the paper said. Camera shake was added to give the effect of filming from a helicopter flying above the National Stadium, known as the ``Bird's Nest.''

``Seeing how it worked out, it was still a bit too bright compared with the actual fireworks,'' Gao told the newspaper. ``But most of the audience thought it was filmed live -- so that was mission accomplished.''

Party Orders

Producers of the opening ceremony also decided 15 minutes before show time to replace 7-year-old Yang Peiyi, who was scheduled to sing ``I Sing For My Country.''

They instead chose 9-year-old Lin Miaoke, who wore a red dress, to lip-synch to Yang's recording, state-run China Central Television reported yesterday. Chen, the music director, told CCTV the switch was made because Lin looked better on television while Yang had a better voice.

``I think it is fair to both,'' he said. ``We have a perfect voice, and a perfect image and representation.''

Recordings of the two girls were circulated all the way up to members of the Communist Party's Political Bureau, whose 25 members represent the country's top leaders, and ceremony organizers were ordered to replace Yang with Lin, Beijing Radio reported.

`Responsibility'

The song was played to welcome China's flag into the National Stadium.

``We have a responsibility to face the audience of the whole country,'' Chen said, according to a translation. ``This is an extremely important, extremely serious matter.''

The revelations sparked debate on Chinese-language Web sites about the values reflected in the show. Stories about the switch elicited more than 2,100 comments on Sina.com yesterday and hundreds more on the portal 21CN.com.

``Hasn't China for a thousand years emphasized having a beautiful heart? This Olympic fake singing really makes China lose all face,'' one poster wrote. ``This is an insult to harmonious society!''

To contact the reporter on this story: Li Yanping in Beijing at yli16@bloomberg.net; Dune Lawrence in Beijing at dlawrence6@bloomberg.net

Last Updated: August 12, 2008 20:18 EDT