Shane Mayer, aged 21, died in hospital three days after he was stabbed outside Gabba's Bar in Forge Road, Darlaston, on July 24, 2019.
The victim, from Wolverhampton, collapsed in a nearby street following the attack at just before 11.15pm. Four men have denied murder.
Investigating officer Detective Constable Claire Ferguson reviewed the CCTV footage and gave evidence to Birmingham Crown Court.
Dc Ferguson said the footage showed profile one, defendant Ramani Sanderson, lunge forward at profile seven, victim Mr Mayer, jurors heard.
The officer said the victim had crouched down and backed up during the incident and dismissed suggestions Sanderson's alleged lunged was toward another person, a judge heard.
She told the court: ""Profile seven [Mr Mayer] is raising his left hand reacting to profile one [Sanderson] and he, Profile 1 [Sanderson], is lunging forward.
"Profile seven [Mr Mayer] is reacting to profile one [Sanderson] lunging forward with a substantial item in his right hand. I don't think it shows profile one [Sanderson] is swinging the item in his right hand towards profile six [another person].
"It's my belief profile one [Sanderson] is swinging the item in his right hand towards profile seven [Mr Mayer]."
Jurors were also told Kamron Reid, profile two in the footage and standing behind Sanderson, had "flinched" when he saw the weapon being produced before the "lunge".
Kamron Reid, 20, of Herberts Park Road, Bloxwich; Ramani Sanderson, 20, of Walsham Road, near Peckham, London; Joseph Till, 21, of Summer Street, Willenhall; and Lewis Green, 21, of Heathfield Lane West, Darlaston, all deny murder.
Sanderson also denies possessing a bladed article in a public place. Green has admitted carrying a hammer.
Sanderson is also standing trial accused of assaulting a taxi driver in a separate incident on April 29, 2019. He is charged with wounding with intent, and possession of a bladed article in a public place. He denies both charges as well.
The trial continues.