A spokesman for the Office of Criminal Investigation in the western state of Hesse did not elaborate on the contents of the videos stored on the computer's drives, saying only that they were of a violent nature and related to Islamist extremism.
Detectives spent much of Saturday combing through documents and data processors that were seized during a search of the couple's Oberursel flat near the city of Frankfurt earlier in the week.
"It will take days or even weeks," the spokesman said.
Authorities arrested the 35-year-old German with Turkish roots and his 34-year-old wife during the raid. A pipe bomb, ammunition, a G3 assault rifle, a grill grenade for a bazooka, and chemicals that can be used to make explosives were also allegedly found at the property.
Detectives believe the couple had been preparing to carry out a bomb attack on a professional cycle race that was to take place on May 1 around Frankfurt. The race was canceled due to the terrorist threat. Police are now trying to determine if the couple had accomplices.
Officers carried out a search along the competition's route on Friday but found nothing suspicious.
Susanne Schröter, director of the Frankfurt Global Islam Research Center, told German news agency DPA it was unlikely the pair acted alone.
"Anyone can build a bomb, but as a rule it is the case that Salafist perpetrators have support around them," she said.
Salafism is the most widespread form of Islamist extremism in Germany, and calls for a return to the way Muslims lived during the Prophet Mohammed's era.
The male suspect is reported to have close ties with the extremist scene in the Rhine-Main area in western Germany, including the Islamist Sauerland group. In 2012, four members of the group were convicted of planning terrorist attacks.
nm/jil (AP, dpa)