The woman, who cannot be named for legal reasons, said she was 17 when Mr Travis indecently assaulted her at the BBC studios in Shepherd's Bush in 1978.
Her friend, also giving evidence at Southwark Crown Court yesterday, said when she watched the episode back later that week it appeared the footage had been edited, just as the victim was "grimacing" next to Mr Travis.
The alleged victim said the two were coaxed to appear on screen next to "big star" Mr Travis as he introduced the next record by the Smurfs. It was then that she was assaulted, the court heard.
Giving evidence behind a curtain, the alleged victim said: "He (Mr Travis) put his arm around myself and pulled me towards him. It was cosy on screen.
"Then he slipped his hand down and put it up my skirt. The skirt would have been lifted from the back.
"I can only really describe it as having a fumble of my bottom area. I think he was trying to get into my underwear."
She said she couldn't remember how the incident ended.
"I felt violated," she said. "The main thing is the camera crew was there, in front of all these people - that's what made it uncomfortable."
The witness's friend, who joined the alleged victim on the set, said the footage of them had been edited down by the BBC - or "shrunk". "The introduction to the (next) record was (originally) a lot longer," the woman said.
The jury heard that the witness told police she thought the footage had been edited by at least six seconds.
"When I watched it back there was just the head part, not the body shot of us, which would have been there originally."
Defending, Stephen Vullo asked if she had colluded with her friend to provide false evidence against the DJ.
The woman, who referred to Mr Travis as "the hairy monster", said: "I'm not."
Mr Travis, whose real name is David Patrick Griffin, denies 13 counts of indecent assault dating back to between 1976 and 2003, and one count of sexual assault in 2008. The 68-year-old, from Buckinghamshire, is accused of assaulting 11 women, one of whom was 15 at the time of the alleged crime.
The trial continues.