Ageing Pell's appeal decision pending

Disgraced Cardinal George Pell has returned to his prison cell as senior judges consider if convictions for molesting choirboys should be overturned.

Victoria's Court of Appeal has been urged to believe the "moving" testimony from one of Pell's victims that resulted in the cardinal being convicted for sexually abusing two choirboys after mass in Melbourne in the 1990s.

With his 78th birthday on Saturday, Pell faces an unknown wait for the court's decision.

Court of Appeal President Chris Maxwell and fellow judges, Supreme Court Chief Justice Anne Ferguson and Justice Mark Weinberg, gave little indication of the outcome as they reserved their decision on Thursday.

"I've said it before that I think juries almost always get it right," Justice Weinberg said.

"The word is 'almost'."

Prosecutor Chris Boyce QC told the court on Thursday the victim stood up to "one of the great old-style cross-examinations" with a calm, reliable and credible testimony in last year's trial.

"He was a witness of truth," Mr Boyce said.

But Pell's appeal barrister Bret Walker SC has argued the jury's verdicts were "unsafe and unsatisfactory".

Mr Walker said evidence from prosecution witnesses showed Pell would greet parishioners after mass at the western door of St Patrick's Cathedral at the time the offending was said to have occurred in the sacristy.

Pell has maintained his innocence and on Thursday his lawyers finished a two-day fight to overturn the convictions and secure his release from prison.

Justice Maxwell described the task faced by him and his fellow judges.

"It's different to 'would I have made that decision myself?'," he said.

"It's 'was it within the range of conclusions reasonably open on that evidence?'"

Mr Boyce defended the victim, now in his 30s, against claims by Pell's trial barrister Robert Richter QC, who accused him of being a calculated liar or deluded fantasist.

After hearing the man's responses to those allegations, "one puts down one's pen and stares blankly at the screen and is moved," Mr Boyce said.

"And at that point any doubt that one might have had about the account ... is relieved."

The judges quizzed Mr Boyce throughout his response to Pell's three appeal grounds, including why the two boys hadn't later discussed the abuse they suffered.

"It's so incredibly embarrassing - do you really want to talk to your friend about it?" Mr Boyce told them, after initially struggling to explain it.

Mr Walker argued it was impossible for him to have committed the "atrocious" crimes.

"If (Pell) was at the western door, then the law of physics tells us this is literally, logically impossible for the offending to have occurred according to the complainant's account, and there is no other account," Mr Walker said.

There was also discussion about Pell's robes, and whether it would have been possible for him to have exposed his penis as he was said to have done, while wearing his Archbishop ornamental robes.

Mr Walker maintained it was not possible for the heavy robes to have been pulled aside, while Mr Boyce suggested the alb, an ankle length tunic, could have been pulled up as far as the cincture, a rope, around Pell's waist.

It was even suggested the judges try on the robes to see for themselves.

Pell is serving a minimum three years and eight months in prison.