June 13 (Reuters) - Synthesia, a UK-based artificial intelligence (AI) startup, said on Tuesday it has raised about $90 million at a valuation of $1 billion from a funding round led by venture capital firms Accel and Nvidia-owned NVDA.O NVentures. "While we weren't actively looking for new investment, Accel and NVIDIA share our vision for transforming traditional video production into a digital workflow," said Victor Riparbelli, co-founder and CEO of Synthesia. AI startups have emerged as a bright spot for investments this year amid a wider slowdown in funding caused by rising interest rates and high inflation.