Meji Alabi is 37, born in London to Nigerian parents. He directs Beyoncé videos. He went back to interview his grandfather about the war. The result is now on BBC iPlayer, in Igbo, Hausa, Pidgin, Yoruba, and French.

There's a version of Nigerian history that exists in the generation that lived it. The soldiers, the civilians, the people who were on both sides of a front line that divided families as cleanly as it divided the country. And there’s the generation after them. The children and grandchildren who inherited the silence.

Surviving Biafra, a 75-minute BBC Africa Eye documentary directed by Meji Alabi, was released on Monday on BBC iPlayer and YouTube. It's available in five languages. Alabi, who won a Grammy for co-directing Beyoncé's Brown Skin Girl video and has directed Burna Boy and Davido, turned this project toward something different from his music video work. He interviewed his grandfather, Godwin Alabi-Isama, a former army commando who fought on the federal side against the Biafran secession. He also spoke with soldiers and civilians who fought alongside his grandfather, and against him.

The war lasted from 1967 to 1970. Between 600,000 and three million people died, many from famine. Allegations of war crimes and genocide have never been properly reckoned with. There has been no truth and reconciliation process. No official Nigerian accounting. The history sits in living rooms and family silences, not in state records.

Alabi said what he made the film because fewer survivors remain every year. "It is now the responsibility of younger generations to preserve these stories before they disappear forever."

The timing of the release is not neutral. IPOB, the secessionist movement in the Eastern Region, remains active. The political temperature in the South-East is not cool. A film that puts federal soldiers and Biafran civilians in the same frame, asking for testimony from both sides, is not a comfort piece. It's a mirror.

What makes Alabi's position interesting is exactly what makes it uncomfortable. He was born in London. He grew up partly in Texas. He made this film because his grandfather's story was his story, even though he didn't live it. That's the diaspora situation in sharp form. You inherit a history you didn't experience. You carry a wound you didn't receive. And at some point you have to decide whether to keep carrying it silently or to ask out loud what actually happened.

He asked out loud. The BBC helped him broadcast it in five languages.

For the diaspora Nigerian watching this from a living room in Peckham or Birmingham, the film arrives as both personal and political. The civil war is not ancient history. It's the reason some families don't speak to other families. It's the reason some conversations at Christmas dinner go quiet when certain topics come up. The wound is still there. Alabi didn't try to close it. He filmed it.

The documentary is free to watch on BBC iPlayer and YouTube. It was released yesterday. It has already started several conversations that were too awkward to have before.