President Carter and visiting West German Chancellor Helmut Schmidt yesterday muted their differences on human rights and other issues in the first of two days to talks.

Both sides reported that they are in agreement on strategy in the 35-nation Belgrade congerence, which is preparing a review of the 1975 Helsinki accords.

West German had been concerned that the Carter administration's aggressive pursuit of its human rights campaign might lead to a confrontation with the Soviet Union in Belgrade, endangering the flow of Germans allowed to return from Eastern Europe and the Soviet Union.

Before Schmidt left Bonn for his current visit to Canada and the United States, his top aides expressed alarm that American policy might "prove counter productive" in dealing with the Russians.

A determination to agree was evident from the opening ceremony on the South Lawn of the White House, where Schmidt was greeted by a 19-gun salute, full military honors and Carter's assertion that "there are no differences between us."

Lauding Schmidt as "one of the world's foremost leaders" and "my good friends," Carter said. "We have frank discussions, as is the nature of Helmut Schmidt."

Schmidt, although he openly favored President Ford in the 1976 presidential election, said the friendship between the two countries "has never been closer than today."

In the information relayed to reporters, the only overt hint of West Germany's strong preference for quieter East-West diplomacy was in Foreign Minister Hans-Dietrich Genscher's report on his talks last month with Soviet leader Lenoid I. Brezhnev, who is strongly critical of overall Carter policy.

Gebscher, a German spokesman said, stressed the importance of personal contact between Brezhnev and Carter to improve U.S.-Soviet understanding.

Schmidt and Carter were said to have expressed their agreement. A recent Carter overture to Brehnev to meet for a general discussion reportedly was rebuffed, however, with Brezhnev expressing a preference to meet only if that could cap an agreement, notably on a new nuclear strategic arms accord.

White House press secretary Jody Powell told reporters at the White House that there was "a high degree of satisfaction" in the Carter-Schmidt talks about progress in the Belgrade conference on the Helsinki accord. Carter assured Schmidt, Powell said, that "there was no desire on our part to single out any aspect [of the Helsinki accords] . . . or any nation, and certainly no inclination on our part to embarrass anyone."

The President and Schmidt also agreed, Powell said, that "it would be beneficial for the Soviet Union to become more involved in multinational activities." In explanation, Powell said this was a reference back to a desire expressed in the London economic summit in May for the Soviet Union to participate in joint activities involving developing and underdeveloped nations.

The longstanding dispute between the United States and West Germany over West Germany's sale of nearly $5 billion worth of nuclear equipment to Brazil, including a nuclear fuel reprocessing plant, was treated only obliquely. Carter without directly re-raising that problem, stressed the interest on "keeping the southern part of this hemisphere a nuclear-free zone."