Amazon.com Inc. is considering an advertising-supported streaming television and music-video service, a departure from its strategy of linking video to its $99-a-year Prime subscription service, according to people close to the company.

The proposed service, as Amazon has outlined it to potential partners, could launch in the coming months and could feature original and licensed content, these people said. As part of the service's development, Amazon has held talks with the creators of "Betas," a series about a...