Trailers could be getting shorter, as cinema owners have demanded that they give fewer plot details away and air nearer to release dates.

According to the Hollywood Reporter, the executive board of the National Association of Theater Owners (Nato), the body set up to represent US cinemas' interests, has issued new guidelines aimed at reducing the complaints they receive in connection with over-promotion of films, and to try and assert control over what is marketed in their cinemas.

The customary practice is for seven or eight trailers to precede the feature attraction, making for a 17-20 minute package; and Hollywood studios rely heavily on these ancillary marketing materials – both in cinemas, on TV and on the web. Nato, however, has called for them to be restricted to 120 seconds in length, and to play not more than five months ahead of release.

This will have considerable impact on both the use of teaser trailers, which tend to be issued well in advance of any release, and the full trailers which are normally well over two minutes long.

According to the Hollywood Reporter, studios fear that the guidelines, though voluntary and which take effect on 1 October, could lead to cinemas refusing to show certain trailers, as well as packing more in to increase payments from studios.