US producers face three powerful creative unions - DGA, SAG and WGA - in the coming showdown on digital rights. Writing in the magazine LA Lawyer, entertainment attorney Brooke A Wharton summarised the confrontation: the unions feel digital downloads should be treated under the same residual agreement as pay television. Producers want to use the home-video rate, which is four times less.

"Unfortunately, there are no appropriate formulas in the respective contracts between SAG, WGA West, WGA East, DGA, Aftra, and Iatse and the studios or networks that specifically cover residuals for new delivery systems such as digital downloading to a video iPod. I am afraid that the digital downloads residuals could be paid at the outdated home-video royalty based on 20% of sales, a formula that has haunted the guilds for almost 25 years."

Directors Guild of America (DGA)
Membership: 13,400
Founded: 1936 (as Screen Directors Guild)
Amptp agreement expires: June 2008
Key issues: new media, wages, health, pension

The DGA represents directors, production managers, assistant directors, technical co-ordinators, associate directors, stage managers and production associates. It has only struck once - on July 14, 1987. The strike, over a proposed Amptp roll-back on rates, lasted five minutes. Typical contract runs three years.

Screen Actors Guild (SAG)
Founded: 1933
Membership: 120,000
Amptp agreement expires: October 2008
Key issues: new media

The most powerful of Hollywood's unions, SAG has used star power. In 1940, Olivia de Havilland sued Warners and won actors the right to term-contracts while Jimmy Stewart was the first actor to earn a percentage of gross receipts in 1950. The longest strike was in 1980 from July 21 to October 23 over terms for pay-TV and video-cassette production. Standard contract runs three years.

Writers Guild of America (WGA)
Membership: WGA West 7,600; WGA East 3,770
Founded: 1933 (as Screen Writers Guild), WGA West and East 1954
Amptp agreement expires: October 31, 2007
Key issues: new media, wages, health, pension

The WGA is considered the most activist of the three major unions. It has struck several times: in 1960 for 150 days, in 1973, and in 1988 for 154 days (the longest in Hollywood history). Standard contract runs three years.