Pontypridd graduate Owain Thomas groomed children online
An aspiring barrister pretended to be a child and used an online gaming currency to persuade children to carry out sex acts on camera.
Owain Thomas, 29, recorded more than 170 hours of material from nearly 150 children - many were under 13 and came from the UK, Europe and United States.
Merthyr Tydfil Crown Court heard it was "merciful" he was caught the first time he approached children in the street.
Thomas, from Pontypridd, admitted 158 child sex charges.
He will be sentenced at a later date.
The charges included causing or inciting children to engage in sexual activity, and watching sexual activity, possessing indecent photographs and distributing indecent photographs.
The court was told the Aberystwyth University law graduate used software to adopt the persona of children and pretended to be girls or boys as young as eight in order to incite others into sexual activity.
The court heard a victim would think they were in a chat with several people when in fact they were just talking with Thomas.
'Like a drug'
Matthew Cobb, prosecuting, said some of the victims were live-streamed to other paedophiles online.
Thomas also used online gaming currency Robux to offer payment to some children to carry out sex acts on camera.
One boy became so accustomed to the procedure that he started to set his own price in Robux, the court heard.
Thomas was caught in November 2018 after approaching two boys, aged six and eight, in the street and repeatedly asking them to expose themselves.
It was reported to police and he was traced through his car's number plate.
When officers called at his home, the court heard that he told them: "I need help, I know I need help. I can't go to prison, I can't cope."
Andrew Taylor, defending, said: "The predatory paedophile interest he had in girls and boys was almost like a drug to him."
He said it was "merciful" Thomas was arrested after the first time he went out to make face to face contact with victims.