According to Vietnam Centre for Protection of Music Copyright (VCPMC), the Vietnamese composer informed them the American TV documentary series "The Vietnam War" had used his song without permission.

With 76 collective management and publishing contracts across 116 countries, VCPMC subsequently collected VND700 million ($30,192) in royalties from the production company. As the series remains on air, the copyright fee is set to increase, meaning the musician would receive greater pay in future.

A helicopter from 336th Aviation Company sprays chemicals over a Mekong Delta
jungle during the Vietnam War, a legacy still affecting local residents today.
Photo by Shutterstock/Everett Historical.

VCPMC explained the American producers had mistakenly assumed the Vietnamese composer to have passed away as the song was composed over 50 years ago, hence failing to seek permission.

The song was performed during several occasions by a band featured in "The Vietnam War" and in another American movie, which acknowledgement the Vietnamese songwriter.

"The Vietnam War" is an 18-hour documentary TV series created by American filmmakers Ken Burns and Lynn Novick. 

In the 10-part series, Burns interviews decision-makers and rank-and-file soldiers. He also spoke to those who did not fight in the war, which set off a protest movement in the U.S., divisions of which can still be felt today.