David ZaslavAnjali Sundaram | CNBCThe TV ad market is on the mend after getting hit by a broader pandemic ad slowdown. But with Covid-19 cases on the rise, some networks are cautious about the coming quarters, even with a big boost from political ads this quarter. In recent days and weeks, media companies including ABC and ESPN parent Disney, Fox, AMC Networks, NBCUniversal parent Comcast, WarnerMedia parent AT&T, ViacomCBS, and Discovery reported earnings that showed the TV ad market warming up after hitting a pandemic-related trough in the second quarter. The record-breaking year for political advertising will give companies a boost in the fourth quarter, but some companies warned that macroeconomic factors as the pandemic rages on could impact ad spend again. And it’s all happening as TV is enduring a long-term overall slowdown. Here are some of the big-picture trends the networks shared in their earnings: Better than when the pandemic startedTV advertising last quarter showed the market is in a better place than the earlier days of the pandemic.At Discovery, third-quarter ad revenue still declined 7.7% from the previous year, but that was an improvement from the 14% decline in the second quarter.”In terms of commercial success, behind the firming advertising marketplace around the globe, we have posted healthy sequential improvement, again, in our advertising revenue growth, which, while still negative year-over-year, is showing demonstrable improvement around the world,” Discovery president and CEO David Zaslav said on its earnings call. “We have seen advertising partners resurface around the globe.”At Comcast, ad revenue increased 12% year-over-year because of political ad revenue, which was up 70% over what it generated during the 2016 election. But the company said core advertising, excluding political, was down 6.8% year-over-year. That’s still a “significant improvement” relative to last quarter. Fox Corp also saw advertising momentum, attributed to strong ratings at Fox News and political advertising.The company’s leadership said that in the quarter ended June 30, which is its fiscal fourth quarter, its local stations were experiencing a year-over-year decrease of about 40% in its base ad market (that is, minus political ads and other non-recurring events). CEO Lachlan Murdoch said on Fox’s call that the equivalent drop in the quarter ended Sept. 30 was only 20%.”Including the benefit of political and station acquisitions, we are now pacing ahead of the same time last year. Looking at it slightly differently, at the beginning of Covid our stations were pacing down nearly 50% compared to the prior year. Today, they are pacing ahead.”ViacomCBS said its advertising revenue also improved dramatically, declining only 6% from a year ago, versus the 27% decline it saw in the second quarter.”We’ve also seen certain COVID impacted industries like auto and retail gradually return, which reflects improvement in the economy and the significant value our portfolio brings to advertisers to drive their own business recovery,” ViacomCBS’ president and CEO Bob Bakish said on its earnings call. “Overall, we’re encouraged by what we’re seeing and big picture advertising is certainly moving in the right direction.” Disney said for its broadcasting unit, ad revenue was comparable year-over-year as lower average network viewership was offset by the benefit of an additional week in the current quarter, higher network rates, and an increase in political advertising at its owned TV stations.Uncertain times ahead after political ad boomDiscovery noted visibility is low following the U.S. election, which helped business in the third quarter, and because of rising Covid cases. The company said its U.S. advertising was flat in October year-over-year, while international advertising was down slightly. “This may not be a trend we would necessarily extrapolate, however, for the full quarter, given, number one, some tailwinds from political advertising in the U.S. in October; and number two, risks from rising Covid case numbers globally and beginning government countermeasures, especially in Europe, which pose risks at the back end of the current quarter,” Discovery CFO Gunnar Wiedenfels said on its call. “That said, we are confident to see sequential improvement in the fourth quarter versus Q3 again.” At AT&T, CEO John Stankey said the sports calendar ahead still has a lot of questions. “Clearly, we’ve seen the leagues demonstrate that they can, in fact, put games on, and they can carry them through. The timing of those and how many there are and exactly what transpires in ’21 and where it falls in the calendar is still a little bit uncertain,” he said on the company’s October call. “And until we have a little better visibility on that, it’s hard to, you know, give you exact views of what first, second, third, fourth quarter looks like next year.”ViacomCBS’ leadership said the return of a stable fall schedule at CBS, along with sports, a “successful” upfront and “hot political category” should help in the fourth quarter. AMC Networks said though the ad market is improving sequentially, results in the fourth quarter will be impacted by timing of its shows, including a delay in the airing of “The Walking Dead.” It said its year-over-year decrease in the fourth quarter ad revenue should be in-line with the third quarter.Content production is ramping upMedia companies largely said they had ramped up production again, after pandemic-related restrictions caused severe disruptions earlier this year. Discovery said its content production was nearly back to normal, with only 10% of the company’s production still paused mostly because of travel and local restrictions. Over at AT&T, Stankey said the company had 180 productions underway in February before the pandemic started. As of October, he said the company had about 130 productions up and running. Meanwhile at Viacom, the company said it estimates production levels are at about 95% of last year’s levels at Viacom Media Network, while CBS “essentially has all of the full network series currently in production” and Showtime is producing “almost all” of its series. At AMC Networks, executives said the company is resuming production activity on a number of its shows, including “The Walking Dead” at its studio in Georgia, “Fear the Walking Dead” in Texas, and a new series called “Kevin Can F*** Himself” in Boston. Fox said all of its Fox Entertainment returning shows are back in production, with scheduled return dates in early January.Disney CEO Bob Chapek said although many of its production teams needed to shut down because of Covid in the beginning of March, its animation teams were able to work remotely and continue production “uninterrupted during the pandemic.” He said on the TV side the company has more than 100 live-action scripted and unscripted projects in active production, with dozens more in other stages of pre- or post-production. Disclosure: Comcast owns NBCUniversal, the parent company of CNBC.