Elisabeth Murdoch can expect a warmer welcome in Edinburgh than her brother

When Elisabeth Murdoch steps to the lectern to deliver the keynote speech at the Edinburgh International Television Festival this week she can expect an altogether different response to that received by her younger brother James just three years ago.

One of the most compelling subplots in the ongoing narrative of the phone hacking scandal has been the changing comparative fortunes of these two Murdoch siblings.

Both have followed their father Rupert into media careers and both are children of his second wife Anna. But one is seen as damaged goods and the other as a force for good. One is regarded with suspicion and the other with warmth.

That polarisation is at its most stark among the British television executives who will gather in Edinburgh this week. They see Liz as one of their own, the founder of Shine, a successful London-based television company that has made hit shows such as Merlin and grown into an international business.

James, for all his achievement in building BSkyB into a British broadcasting success, was seen by the TV industry as the embodiment of the values of his father's News Corp empire and a threat to the future of the sector. When he addressed the Edinburgh audience in 2009 he was "a provocateur", says Elaine Bedell, the festival's executive chair. James responded to the challenge with an extraordinary attack on the BBC, establishing him as a pariah figure.

Elisabeth, the first woman in 17 years to give the prestigious MacTaggart lecture, will get a less prickly welcome. The big question is, now that Shine has been subsumed into News Corp and Liz has a place on the board, whether she will use this moment to position herself for a greater role in her father's business, ahead of a crucial shareholder meeting in Los Angeles in October when the future leadership of the organisation will be under discussion.

"Liz is undoubtedly a very senior executive in the television industry and running an incredibly successful global [independent company], I suspect she will range quite widely," says Bedell. "Who knows what she is going to say?"

So much has happened to the television sector since that provocative address by James Murdoch in 2009. Back then the atmosphere in Edinburgh was one of deep gloom. James's pointed comments on the "chilling" ambition of the BBC were designed to find favour among vulnerable commercial television executives who were watching advertising revenues go south. ITV, where Bedell is now head of entertainment and comedy, was seen by some as a basket case.

This year the mood will be rather different. ITV, in particular, has been turned round under chief executive Adam Crozier and the share price has risen to 82.9p from a frightening 22.3p in 2009.

BSkyB – castigated at Edinburgh in 2010 by the BBC's Mark Thompson for its failure to originate British content – has repositioned itself as a programming powerhouse and its festival delegates can hold their heads high. The BBC arrives at Edinburgh on the back of its triumphant Olympics coverage. "I think people are feeling a bit more buoyant," says Bedell.

Advertisers have realised the continued impact of television, particularly when used in conjunction with social media. Bedell points to a year in which momentous occasions, from the Diamond Jubilee to the London Olympics have shown "the power of live television and events" and proved wrong those who suggested we were moving to an era of TV as a more solitary experience, self-scheduling our favourite shows on mobile devices.

But 2013 will be different, with no obvious broadcasting spectaculars in the calendar. "There's nothing next year – we need to grow some of our own," Bedell says. Her role at ITV, where she oversees big Saturday night shows including The X Factor and Britain's Got Talent, means she has a responsibility for delivering event television.

She is also bringing the half-hour sitcom back to ITV, with shows featuring Ricky Tomlinson and Russell Tovey. Indeed, comedy will be to the fore at Edinburgh this week with Al Murray, Ruth Jones and the Modern Family creator Steve Levitan helping to reflect a happier industry.

It's into this environment that Elisabeth Murdoch will arrive to give her big speech. The Edinburgh Television Festival is sponsored by The Guardian, which has been such a fierce critic of her father and brother over their handling of phone hacking and their attempts to take full control of BSkyB. Will Liz come in peace or carrying the News Corp banner? And will she, like her brother, be prepared to wipe smiles from faces?