US performance artist Laurie Anderson pays tribute to her late husband Lou Reed in "Heart of a Dog," a cinematic contemplation of love and death that also covers the loss of her mother and her beloved pet terrier.

Anderson, who was married to the Velvet Underground singer for 21 years before his death in 2013, has made loss the central theme of her first film since 1986's "Home of the Brave."

"As an artist I have made music, paintings, installations, sculpture and theatre," she said after the premiere of her new work at the Venice film festival on Wednesday. "But most of all I am a storyteller.

"Making Heart of a Dog was a way to translate my work into a form I've never used in this way."

Anderson's voice is a constant presence in a challenging, experimental documentary which blends strands including stories of her dog Lolabelle, her mother, her childhood fantasies and her Buddhist-influenced philosophical theories into a visual collage set to a soundtrack of her own music.

From the raw materials of her life and art, the 68-year-old artist seeks to examine how stories are constructed and told and how they can help to give meaning to life.

She recounts her own life, her childhood in Illinois, her memories of 9/11 in New York and also the final days and last breath of her blind dog.

"You should try to practise how to feel sad without actually being sad," her Buddhist teacher would tell her, articulating one of the dominant themes of a film which, without ever mentioning Reed by name, is nonetheless an ode to his memory.

"The spirit of Lou is very present in the film," she said. "I wanted to do something that was a homage to my husband but also respected part of his personality. In particular, I wanted the film to reflect his great energy."

- Childhood memories -

Anderson was originally commissioned  to produce the film by Franco-German public television station Arte as part of a series featuring artists talking about the meaning of life and work.
The version shown on Wednesday is longer and underscores Anderson's lifelong fascination with language and technology.

Much of it was shot on her iPhone and other small digital devices.

From an imaginary sequence in which she gives birth to her dog to a section in which the narrator describes the final moments of her mother's life, much of the film has a dreamlike quality.

While viewing family footage from her childhood she remembered an episode in which she saved her twin brothers from drowning in a frozen lake, and she also recounts an accident in which she broke her back in a swimming pool.

Another story describes how Anderson arranged for music and painting lessons for Lolabelle when she started to go blind.

And Reed provides the final note with his song "Turning Time Around," playing over the closing credits.