A former music teacher has been given a 25-year sentence in jail for the hundreds of child sex offences he has committed for more than 12 years.

Colin Doo, from Romsey in Central Victoria, pleaded guilty last March to 39 counts of child sex abuse, which was done between 1996 and 2008.

They include rape and procuring a minor for child pornography.

The court has heard that Doo was a music teacher and video editor. He made friends with the families of his 11 victims in a local primary school.

Most of his offences were recorded through the cameras hidden all over his makeshift bedroom.

Judge Paul Coughlan said that he considers this case to be one of the most obnoxious he had ever dealt with in his entire legal career.

He said that Doo's behavior was a "sophisticated, gradual and long-term process of grooming."

It is one of the longest sentences given on a pedophile in Victoria's history.

Doo may apply for parole in 22 years and has been registered as a sex offender for life.