BEIJING — The trailer for “Doctor Strange” from Marvel Studios has ignited outrage against what some people call another example of Hollywood’s racially insensitive casting. It reveals that a Tibetan character from the comic book, the Ancient One, is played by Tilda Swinton, a white British actress.

It turns out that the filmmakers scrubbed the Tibetan origins of the character from the comic book altogether, in large part over fears of offending the Chinese government and people — and of losing access to one of the world’s most lucrative film markets, according to one insider account.

In an interview last week, C. Robert Cargill, a screenwriter, offered that as an explanation for why the Ancient One was no longer Tibetan.

The Tibetan issue is one of the thorniest involving China and other nations. The Chinese Communist Party and its army occupied Tibet in 1951, and Chinese leaders are well aware that many non-Chinese believe that Tibet should have independence or greater autonomy.