AUSTIN, Texas -- The record industry might not be on an entirely even keel, but the South By Southwest Music Conference & Festival appears to be recession-proof.

Beginning Wednesday, thousands of music industry professionals and entry-level aspirants descended on Austin for the annual confab, which now serves as perhaps the best available barometer of the state of the business.

During daytime sessions Wednesday and Thursday, panelists alluded to the industry's ongoing struggles. But the troubles haven't put a crimp in the 18-year-old music conference's style.

SXSW managing director Roland Swenson estimated that about 9,000 would attend the conference in an official capacity this year; that number includes volunteers and performers.

Swenson said he believed that attendance would be up at least 10% this year, with walk-up registrations on the increase.

If the music industry still is suffering from a decline, it would have been difficult to determine it Wednesday while standing in the lobby of the Austin Convention Center, site of the conference panels. The increase in traffic flow led to long registration lines; some conventioneers reported it took 1 1/2 to two hours to secure their badges.

Explaining the boost in attendance, Swenson said, "We're coming off three or four years that have been pretty productive for people."

He added that burgeoning international participation was a probable source of the increase. An SXSW spokeswoman said that about 300 international acts would be performing in Austin during the evening festival shows.

"It's a really broad base of customers," Swenson said. "If any one segment is having a bad year, we're not crippled." He noted that business conferences that have cast a narrower web, like the now-defunct Gavin radio convention, faced tougher sledding: "When that (radio) market changed, there wasn't anything left for them."

SXSW, which began life as a showplace for independent regional talent, now plays host to dozens of U.S. and foreign indie labels. "A number of independents are having their best years ever," Swenson said.

For music industry types, and most especially for performers, SXSW remains the place to see and be seen. This year, between 1,200-1,300 acts will be on view at 59 official festival venues in Austin. Many more have taken to the clubs for an expanded lineup of daytime parties and events, which Swenson described as "a double-edged sword."

"We have to struggle to program (the conference panels) against the parties, so that everyone doesn't leave the convention center," he said.

SXSW even has taken to mounting its own daytime shows at tiny Brush Square Park directly across from the convention center to keep conventioneers suffering from temporary cabin fever close to home.

Those who opted to hunker down in the panel rooms heard oft-sobering views about the current state of affairs in the music biz.

Jacob Slichter, former drummer for the Minneapolis band Semisonic and author of the wry memoir "So You Wanna Be a Rock 'n' Roll Star," said Wednesday that it's tougher than ever for a young band to secure ongoing label support these days.

"I don't know if there are any artist development labels left," Slichter said, getting a nod of assent from eMusic editor-in-chief Michael Azzerad, who hosted the interview session.

Singer-songwriter Elvis Costello, now a Universal recording artist after long tenures at Columbia and Warner Bros., reflected on the changes he has witnessed in the business during an interview conducted by MTV Networks senior vp Bill Flanagan.

"The creative people inside the companies have become increasingly invisible," Costello said. "They box in the creative people inside this massive and unwieldy structure, which resembles the last days of the dinosaurs."

Costello also accused specialty music retailers, who have faced stiff competition from online music services, of being woefully behind the times and out of touch with consumers.

"As soon as broadband is big enough, the record (retailing) business is over," Costello said. "They will have to change or die ... It's going to be about five minutes to the end. All bets are off." He added that traditional music chains like Tower Records had "let the spirit go out of it."

Although Wednesday's panels largely were devoted to "crash courses" aimed at the musical aspirants who flock to SXSW every year, the conference rolled out the heavy artillery -- former Led Zeppelin lead vocalist Robert Plant -- for its official opening session Thursday. In a major outburst of fan love, hundreds packed into the panel room to see Plant; dozens more watched the session on closed-circuit TV in the hall and an adjacent room.

Plant -- whose induction into the Grammy Hall of Fame was acknowledged onstage by Recording Academy president Neil Portnow -- stuck mainly to Zeppelin war stories during his interview. Some in attendance felt his appearance was an extended promotional opportunity for his forthcoming album, "Mighty Rearranger," due May 10 from Sanctuary Records.

But even the heavy metal overlord noted the narrowcasting of contemporary music. "I hate the idea that the jukebox is based on five songs, mass popularity," Plant said. "Even the term 'rhythm & blues' has gone into a kind of cabaret now."

On Wednesday night, the first night of the SXSW festival, downtown streets were filled with conference attendees, plus 14,000 locals and out-of-towners who had purchased wristbands admitting them to evening musical events.

With all the heavyweight talent in town, rare events were on view. A couple of headliners turned up at the venerable blues club Antone's: Costello sat in on a version of Howlin' Wolf's "Hidden Charms" with the late bluesman's guitarist Hubert Sumlin and guest pianist Pinetop Perkins, Muddy Waters' longtime keyboardist, as Plant watched the proceedings with other fans in the crowd.