Formula One will have a draft 2019 calendar by the end of August but there could be only 20 races, with Germany out of contract and a proposed round in Miami still in the early stages.

F1 commercial manager Sean Bratches said at Sunday's German Grand Prix that next year's schedule would be published before the Belgian race at Spa-Francorchamps on August 26.

He would not be drawn on the number of races but Miami city authorities are not due to take any decision on what would be a second United States round until after their August recess.

Sources said Formula One had already accepted Miami would not feature on the calendar until 2020 at the earliest.

Bratches said F1 wanted to keep Germany, home of champion Mercedes and Ferrari's Sebastian Vettel, on the calendar — hopefully from next year.

Whether that is Hockenheim or somewhere else remains to be seen, however.

"Our interest is in remaining in Germany," said Bratches. "We have three countries out of 21 where the government doesn't underpin the grand prix — Austria, Britain and Germany. So we're trying to find an appropriate way around that. We're not ready to wave the white flag yet on Germany for 2019."

"Everybody's interested in making a deal. And there's multiple circuits in this wonderful country," he added.

Jorn Teske, the Hockenheim marketing director who has been actively engaged in negotiations, said that the choice really came down to his circuit or the Nuerburgring — which has also been unwilling to pay the hosting fees demanded.

He dismissed suggestions that a street race could be organized in Berlin, given that a fan festival scheduled for the week before the German Grand Prix never got off the ground.

"I don't believe in this in Berlin, not at all," he said. "For several reasons, not just money but also the political situation there. I try to imagine which other city in Germany it could be but no ideas.

"It doesn't really make sense. It might be a good show but to build the whole infrastructure... to have this very difficult discussion in Germany about cars, all these diesel (emission) scandals, I cannot imagine it," he said.