The spectre of digital rights haunted this year's Berlinale.

"It's a difficult market in general because of anxieties over VoD (video on demand)," admitted Celluloid Dreams' Charlotte Mickie.

The potential of new platforms is a mainstream issue but quantifying the value of downloads, VoD and online distribution is tough. Smaller content owners complain of pressure to hand over rights.

"It's a real land grab at the moment," Gregor Pryor, associate at global law firm Reed Smith, told the Screen International-backed Arts Alliance Media digital debates series at the EFM. "Everyone wants to experiment with these new platforms but they want to do it at the expense of the content owner."

Victoria Gaskell, a media law specialist at UK legal practice Olswang, suggests it may grow into an issue to be addressed by an industry regulator.

For many sales companies, the response to the challenge was simple - a refusal to sell.

David Glasser, sales chief at Bob Yari's Syndicate Films said: "We're holding back on selling internet rights until we find out more about it. We want to be comfortable with the anti-piracy technology and we want to value the rights accordingly."

Samantha Horley of UK-based Lumina Films said the situation was similar to the DVD rights issue of the 1990s, creating tensions between buyer and seller. "There are so many producers who want to hold onto the VoD and internet rights," she said. "It's just people trying to find ways to exploit rights without knowing what they are."

Kimmel International sales chief Mark Lindsay and Voltage Pictures sales chief Nicolas Chartier both said they were freezing rights on many products until the market values and legal situation were clearer.

Mark Horowitz of H20 Motion Pictures said: "This is the future. Theatrical distribution could become a promotional window and VoD could become more important."

The debate will heat up in the approach to Cannes.