A teenager has told a County Court jury he was "scared and panicked" when he filmed a Victoria Police officer allegedly punching his friend in the jaw, after the pair were falsely accused of committing burglaries.

Stuart Laird was 16 years old when he and his friend, Kyan Foster, 17, were walking home from a party where they had smoked marijuana in the early hours of Christmas Day, 2014.

The teens were approached by police officer Simon Mareangareu as they waited at traffic lights on Canterbury Road, in Ringwood in Melbourne's east.

"It was a bit strange, never been approached by police," Mr Laird told the court.

"I pulled out my phone and started recording."

The court released video of the incident to the media on Friday, noting it was not complete, did not capture the whole incident, the video had been enhanced, and the audio was not properly synchronised with the video.

In the footage, Mr Mareangareu demands the teenagers' names and addresses, telling them they were suspected of committing burglaries.

He then grabs Mr Foster's jumper, after accusing him of being a "smart arse".

When Mr Foster protests, Mr Mareangareu is seen swinging his arm towards the teenager and tackling him to the ground.

It's alleged the officer punched Mr Foster in the jaw.

"It was real loud," Mr Laird told the court.

"He went down, and fell to the ground."

Simon Mareangareu (left) and Dennis Gundrill have pleaded not guilty. ( Supplied: Eddie Jim/The Age )

Mr Mareangareu has been charged with intentionally causing injury over the alleged punch.

Mr Mareangareu and fellow police officer Dennis Gundrill have also been accused of deleting the video footage of the incident, or assisting in the deletion of the footage.

The pair are facing charges of false imprisonment, attempting to pervert the course of justice and perjury.

Both men have pleaded not guilty to the charges.

Teen was 'scared and panicked'

The court heard the footage does not show the point of contact during Mr Mareangareu's alleged punch.

The first part of the footage comes to an end after a voice is heard saying, "get rid of [the] video right now".

"I was a bit scared and panicked," Mr Laird told the court.

"I just wanted the situation to stop."

Mr Laird said he started recording again about 10 seconds after pressing pause.

"I just realised I don't have to stop this," Mr Laird told the court.

Mr Laird was found to have 1.75 grams of marijuana and a bong in his bag.

Both boys were charged with possessing marijuana, assaulting and resisting police over the incident.

Mr Laird told the jury his mobile phone was also taken from him, and he accused Mr Gundrill of saying: "If you get rid of the video we can make this go away."

Mr Laird told the court he discovered the mobile phone video had been deleted shortly after being released from custody at 5:00am.

The footage released to the court is a recovered version of the deleted video.

One of the teen's fathers paid experts to recover the deleted videos.

The trial continues.