CD Projekt Red used AI to alter the voice of Geralt's original Polish actor in Witcher 3: Songs of the Past

In The Witcher 3's Songs of the Past expansion, CD Projekt Red utilized AI to modify Jacek Rozenek's voice, Geralt's original Polish actor. Rozenek experienced a stroke in 2019 that left him unable to speak, necessitating six to seven hours of daily voice training for his recovery. He briefly returned to voice Geralt in the 2022 next-gen update but found it exhausting. CDPR sought his voice again for Songs of the Past, acknowledging that his voice had changed significantly over the past 12 years.

CDPR's localisation producer, Mikołaj Szwed, stated that the difference in voice could disrupt the experience for players. To address this, they turned to Ukrainian AI company Respeecher, with Rozenek's consent. Rozenek expressed trust in the game's creators, acknowledging the difficulty of achieving a voice close to his younger self. CDPR had previously worked with Respeecher to recreate the voice of Miłogost Mięciok, who voiced Viktor Vektor in Cyberpunk 2077 after his death in 2021.

Respeecher trained an algorithm on Rozenek's 2014 recordings to adjust his current voice. The process required dozens of hours, addressing AI artifacts and capturing Rozenek's emotional range, including shouts, groans, anger, fear, and laughter. CDPR's contracts ensure they won't use an actor's voice with AI without consent. Szwed believes this approach demonstrates ethical AI use with consent, for a positive purpose.

The use of generative AI in voice acting remains a contentious topic, with Japan Actors Union releasing new guidelines and UKIE partnering with law firm Sheridans to provide an AI Compliance and Accreditation Service.