Magnotta, 29, was arrested in Berlin while reading about himself at an Internet cafe on Monday after an employee recognized him from a newspaper photo and flagged down a police car.
A copy of the video viewed online by The Associated Press did not show anyone eating the body but did show a man using a fork and knife on it.
Magnotta appeared before a German judge in the afternoon and was ordered held pending extradition, police spokesman Thomas Neuendorf said. He was then transferred to a Berlin prison from a police detention center.
He will have to go before a German court for an extradition hearing once Canada formally requests that he be returned for trial, Neuendorf said.
"I assume there will be no problems," he said. "According to his statements to prosecutors he will not fight his extradition."
That means Magnotta could be returned to Canada as early as this week, according to authorities. The Canadian Embassy in Berlin declined to comment on when Ottawa may file the official papers seeking extradition.
Magnotta arrived in Berlin on Saturday on a bus from the French capital, Paris, said Martin Steltner, a spokesman for Berlin prosecutors. He would not elaborate on what Magnotta did in Berlin between his arrival and the time of his arrest, citing the ongoing investigation.
Magnotta is wanted by Canadian authorities on suspicion of killing Jun Lin, a 33-year-old man he dated.
Authorities allege Magnotta filmed the slaying in his Montreal studio apartment and posted it online. The video shows a man with an ice pick stabbing another naked, bound male. He also dismembers the corpse and performs sexual acts with it.
The case's full horror emerged when a package containing a severed foot was opened at Canada's ruling Conservative Party headquarters on May 29.
That same day a hand was discovered at a postal facility, addressed to the Liberal Party of Canada. And a torso was found in a suitcase on a garbage dump in Montreal, outside Magnotta's apartment building. Police in masks combed through the blood-soaked Montreal studio apartment last Wednesday.
As they unraveled his background, police discovered that Magnotta changed his name from Eric Clinton Newman in 2006 and that he was born in Scarborough, Ontario. He is also known as Vladimir Romanov.
Montreal police on Tuesday said DNA tests have confirmed that the parts mailed to the political parties were those from Lin's corpse, and that they have footage of him mailing the two parcels that were sent to Ottawa.
"The head is still missing," Lafreniere said. "And one hand and one foot is still missing."
He said they had no indication those parts had been shipped anywhere, however.
Zheng Xu, a press spokesman at the Chinese consulate in Montreal, said press attache at consulate, said Lin's family has been contacted and wants to come to Canada as soon as possible. He said he was not able to give any further details without the family's approval.
In Germany, surveillance camera footage of the cafe, obtained by The Associated Press, showed Magnotta casually entering the shop at noon local time wearing jeans, a green hoodie sweater and sunglasses. He briefly spoke to the counter clerk, then walked to his assigned computer where he was later spotted reading news about his case.
About two hours later, seven German police officers walk into the shop, without any haste. The footage shows three police officers accompanying the handcuffed Magnotta a couple of minutes after they first entered the cafe. Magnotta calmly walks alongside them.
Police say he at first tried giving fake names but then conceded: "You got me."
In recent days, French authorities were growing increasingly confident that Magnotta would be caught, especially after an Interpol alert meant photos of him were distributed in newspaper pages and TV screens worldwide, and via the internet to PCs and mobile phones.
A National Police official told the AP that French authorities went over closed-circuit video footage from an international bus station in Bagnolet, northeast of Paris, and turned up images of Magnotta getting on bus bound for Berlin. The official spoke only on condition of anonymity because of judicial secrecy in the case.
Christophe Crepin, a police union official, said German officials had already been alerted that Magnotta might be in Berlin at some point ahead of the arrest, but he did not specify when.
At times, however, French investigators grew frustrated with leaks in the media notably a French TV report indicating police had used technology to track his mobile phone's whereabouts. As a result, he turned it off, Crepin said.
"He had closely monitored what we police were doing to concoct his strategy."