After a slow start, Coldplay warms the Coachella night.

Indio -- Think of the Coachella Valley Music and Arts Festival as the rock ‘n’ roll equivalent of TiVo. It’s a way of seeing your favorite acts and exerting control over the clock.

You could have sampled more proven and promising acts in Saturday’s 11-hour-plus program at the Empire Polo Fields than in four weeks of club-going -- including getting a preview of Coldplay’s new music, checking some highly touted new British arrivals and exploring the injection of hip-hop, which had been largely neglected in past years at Coachella.

If one band didn’t prove interesting, you could simply move to another stage. In TiVo terms, it’s the equivalent of hitting the delete button.

This revolving-door option puts pressure to deliver on the day’s nearly four dozen acts, because there is music on five stages virtually at all times.

No one faced more pressure Saturday than Coldplay, the British quartet whose dramatic rise (more than 20 million albums sold in four years) has created as many skeptics as fans. Is there really any depth behind all that rush of sensitivity?

Coachella has evolved since its 1999 inception into the nation’s leading rock festival, a two-day affair whose tastemaker influence goes well beyond the 50,000 or so fans who attend the event each day. This year’s lineup was superbly diverse, perhaps the best, top to bottom, of any of the six Coachella shows.

Media and industry observers from across the country as well as far away as Britain and Japan start spreading judgments as soon as bands leave the stage -- and lots of people are waiting for the verdict on Coldplay’s new music. Its “X & Y” album is due early next month.

The group started sluggishly, doing little in its music or manner to reach out to the thousands of fans huddled in front of the massive main stage in the chilly evening that followed a lovely 85-degree day, a relief from last year’s punishing triple-digit peak heat.

Things were so bad for Coldplay that low clouds blocked any sign of the stars in the outdoor feeling, undercutting the opportunity for fans to fully celebrate when Chris Martin sang, “Look at the stars, look how they shine for you, and everything you do” -- the key line in the group’s biggest hit, “Yellow.”

Martin tried to have fun with the moment, switching one reference to the song title from yellow to Coachella.

But the breakthrough was when Martin and mates finally got to the loveliest and most personal songs from the new album. In retrospect, he might have turned to those songs earlier to set an intimate, personal mood for the hour-plus performance.

There may be nothing harder than playing music whose fundamental appeal is its sheer loveliness. It’s easy to be angry or cynical or ironic, but there’s not much room for error if your strength is in music that is open and warm-hearted. It’s easy to slip into greeting-card sentimentality or numbing calculation.

But Coldplay has mastered loveliness. The band (also including guitarist Jonny Buckland, bassist Guy Berryman and drummer Will Champion) plays in ways that are both caressing and majestic, and Martin, who moves between piano and guitar, sings in a falsetto-edge style that adds intensity to his lyrics.

The band’s impact soared dramatically when all four gathered at the front edge of the stage for an acoustic version of “ ‘Til Kingdom Come,” a country-accented song written for the late Johnny Cash and a highlight of the new album.

It was a gorgeous statement of devotion, and the audience responded warmly -- and wouldn’t you just know it? In one of those moments of pure showbiz magic, the clouds opened enough for a handful of stars to shine through.

The rest of Coldplay’s set was equally inspired as the group focused on more delicate new tunes, including “What If” and “Fix You” -- wonderfully moving songs that proved the group is one of the most compelling bands of recent years.

In a far different look at love, London based-duo the Kills stepped on a much smaller stage five hours earlier in the stuffy and colorless Mojave Tent to sing about relationships. The music is often dark, tortured and unsettling. Of the many groups that have been influenced by the harsh, rock-noir style of the Jesus and Mary Chain, the Kills may come closest to the original vision.

Between these extremes, other Coachella acts dealt with love in various forms, such as the gentler, rock-noir style of the Raveonettes, the Danish team with lots of Phil Spector and Blondie influences, and the superficial romanticism of Keane, a British band that reaches for the beauty of Coldplay but sometimes ends up as slight as Air Supply.

Because there were nearly four dozen attractions Saturday, picking favorites became an all-day obsession. If the first question friends asked when meeting Saturday wasn’t “How was the traffic?” it was probably “Who have you seen, and were they any good?”

There was lots of interest, quite deservedly, in Los Angeles’ own disarming, art-country Rilo Kiley, a group with an exquisite sense of individual style, and Bloc Party, whose Clash-like urgency proved to be one of the evening’s highlights. There was also a buzz on the hip-hop acts and a vow to check out more of it Sunday.

By the end of the long day, it was still clear, however, that the real star of Coachella is the festival itself.

As fans headed for the parking lot after Coldplay ended just after midnight, you could still hear spirited debate over which bands they wanted to add to their iPods and which they planned to delete from their must-see list.

For those planning to return for Sunday’s closing program, there also was the excitement in knowing that the whole process would begin again in less than 12 hours.