(Reuters) - Viacom Inc VIAB.O and Charter Communications Inc CHTR.O agreed on a short-term extension of their renewal deadline, a source familiar with the matter said, as the companies aim to avoid the immediate blackout of Viacom networks.

If no deal is reached, 16.6 million subscribers of Charter’s Spectrum service will lose Viacom’s networks, which include Comedy Central, MTV and Nickelodeon.

Viacom and Charter are working to “reach a mutually beneficial deal,” said the source, who did not want to be identified.

Viacom stands to lose $760 million, or about 16 percent, of its annual affiliate revenue if an agreement is not reached, according to an analyst at Gabelli & Co, Viacom’s second-largest voting shareholder.

Both sides are under pressure from cord-cutting, or dropping of pay television, as audiences flock to cheaper streaming services that have emerged in the past decade.

An agreement between the two companies would be “mutually beneficial,” wrote Evercore ISI in an note Sunday.