LOS ANGELES — Negotiations aimed at preventing a crippling strike by Hollywood movie and TV writers are down to the wire.

That the Writers Guild of America and the Alliance of Motion Picture and Television Producers talked over the weekend and were resuming Monday was a hopeful sign. The current contract expires at midnight PDT Monday.

But with both sides observing a strict news blackout, there was no official indication of how close they are to a deal on key issues including compensation and health care.

Continued negotiations are encouraging but not a guarantee of an “acceptable deal,” according to a Sunday memo to guild members on behalf of WGA negotiators.

Members were advised to remain ready to strike as they await what should be “something substantive” on progress by Monday or Tuesday morning, the memo said.

Producers reportedly have agreed to contribute more to the guild’s health plan and increase earnings for writers working on series with fewer episodes.

The previous writers’ strike lasted 100 days in 2007-08 and was costly to the businesses that serve Hollywood and to consumers expecting to be entertained.

Last month, WGA members voted overwhelmingly to authorize a strike.

A walkout’s impact would come in waves and affect different parts of the industry differently. Here’s a look at how it could play out if writers trade their laptops for picket signs.

THE ISSUE

The changing nature of how television is delivered to viewers is a major reason for the impasse.

More than 400 series were available on broadcast, cable and rapidly expanding streaming platforms this season, double that of six years ago. But shows have fewer episodes than the roughly two dozen per season once common on network TV, and short runs of as few as eight to 12 episodes mean less money for writers getting paid on a per-episode basis.

Contracts binding writers exclusively to a series have cut into their compensation as well.

According to the WGA, which has about 20,000 members, median earnings for writers dropped between the 2013-14 and 2015-16 seasons, and more scribes are finding it difficult to make a living under current deals.

The guild is seeking a wage increase and wants salary minimums to apply equally to streaming, cable and broadcast. Health care, an issue that echoes beyond Hollywood, also is on the table. The two sides are at odds over what concessions the guild would make in return for producers contributing more to the health plan.

TELEVISION

TV viewers won’t be laughing much if writers take a hike, with the most immediate impact on late-night talk and comedy shows including “Saturday Night Live.”

In the 2007 walkout, shows including NBC’s “Tonight” and CBS’ “The Late Show with David Letterman” went dark for two months. They returned during the strike either without writers or, in Letterman’s case, with a separate guild deal through his production company. That won’t be an option for CBS’ current “Late Show” host Stephen Colbert because a CBS entity now produces it.

For prime-time TV, the strike would come as the fall-to-spring broadcast season winds down. But with year-round programming now commonplace, networks and cable channels likely will call on reality shows to help fill the void.

Reruns, sports and news also would be key, said entertainment lawyer Jonathan Handel. Streaming services such as Netflix and Amazon could be winners because their original series tend to be produced further in advance of release, he said.