A former music teacher has been jailed for at least 22 years for sexually abusing 11 girls and filming the assaults on hidden cameras.

Colin Doo, 51, from Romsey in Victoria, pleaded guilty to 36 counts of abuse, including rape and procuring a minor for child pornography.

Victorian Supreme Court Justice Paul Coghlan on Friday said viewing some of the video of Doo's abuse was "one of the most unpleasant tasks" he has had to undertake in his legal career.

Justice Coghlan sentenced Doo to 25 years and seven months in jail, with a minimum term of 22 years.