The court ruled in favour of Dallas Buyers Club LLC's request for access to the customer details of 4,900 people who downloaded the film over peer-to-peer services over a seven-week period in 2014.
However, the ruling sought to balance the filmmaker's right to be protected from copyright infringement against the privacy rights of the customers.
The possibility of the film's rights holders sending out speculative invoices and claiming large sums of money was not a good enough reason to refuse to give IP addresses, Justice Nye Perram said. However, templates of letters to the alleged pirates must be sent to the court for approval, to protect the privacy of the individuals concerned.
The court accepted evidence given by expert witness Dr Simone Richter who told the court that software can be used to identify accurately the IP addresses of users and the time of data transfers, and that the use of dynamic IP addresses does not affect the accuracy of that identification.
It is plausible that a person who downloads a film using a peer-to-peer network is infringing Australian copyright law, Justice Perram said, even if the person does not have access to the full film, or a substantial part of it.
"I am comfortably satisfied that the downloading of a sliver of the film from a single IP address provides strong circumstantial evidence that the end-user was infringing the copyright in the film," he said in the judgment.
"It is sufficient that the contemplated suit has some prospect of succeeding, that is to say, it is a real case which is not fanciful …. I do not regard as fanciful the proposition that end-users sharing movies on-line using BitTorrent are infringing the copyright in those movies. Indeed, if there is anything fanciful about this, it is the proposition that they are not," Justice Perram said.
Technology law expert Luke Scanlon of Pinsent Masons, the law firm behind Out-Law.com, said: "Rights holders will see this as a step forward in their efforts to fight against online infringement and gain some comfort that the court has taken an approach consistent with that of courts in other jurisdictions. ISPs will now need to revisit the protections they offer or claim to offer their customers in terms of keeping their personal information private."