Huang Yue-mei has been "in the pictures" now for over 20 years and has made some 253 films. But she has never recited a line or spoken a word on camera, and no moviegoer remembers her.

The set is abustle--lightmen putting up their equipment, propmen rushing around taking inventory, makeup artists putting the finishing touches on the leading actors. . . . But one group, colorfully arrayed, stares glumly at all the commotion, not quite a part of it all.

"Let's go!" shouts the casting director, pulling at a sleeve. "Stop staring and get a move on it. Maybe you'll be a big star yourself someday!"

"Big star, my eye!" a bald-pated "monk" mutters, tugging his sleeve back.

After the show, who remembers, when the romantic leads had that tete-a-tete in the cafe, what the fellow looked like at the next table? Or what people played the crowds that fled terrified from the earthquake?

All are extras, the least noteworthy and least noticed figures on the screen. But, Chinese or foreign, scarcely a movie is without them. Most films use less than 100, but a war picture or a costume drama may need 400 or 500. The 1965 Chinese historical epic "Hsi Shih" is said to have used 120,000, with help from the army.

Extras are the migratory birds of the film world; they collect and disperse according to the industry's economic climate. And they come in all feathers.

The women bear less of a psychological burden than the men. Most are housewives, introduced through a friend, who want to have some fun and make a little spending money. Others are clerical workers off for the day.

The children are brought along by their mothers or specially bussed in from a school. Relaxed and happy, the kids take it all as a big game.

But for the men it is a more serious affair. They are mostly in their forties, fifties, or sixties, with no fixed employment. They are retired servicemen, failed businessmen, runaway husbands, people who cannot work a steady job, and such. "The young fellows aren't interested in this kind of work," says a 60-year-old cabdriver, retired because of an accident.

Sometimes a special kind of bird is required. A scene in one TV series was to show the birthday banquet for old Mrs. Kao and her rich and powerful friends. Where to find some extras with extra class? The producer got up at 4 a.m. and went to a park in a fashionable Taipei neighborhood. There he rounded up 30 or 40 distinguished old ladies and gentlemen who were gathering for their morning exercise. They went along out of curiosity, but when they found themselves repeating takes under the hot lights, several old ladies began making noises about "going on strike." Only the most assiduous entreaties from the director saved the situation.

Barring special circumstances, however, most extras are recruited in one of two ways: housewives and children by a telephone call from the casting director, and men by a visit to one of their favorite "roosting places"--inside the rest station under Taipei Bridge, in front of the Matsu Temple in Yenping North Road, or around the bronze statue at Sun Yat-sen Hall.

The men begin gathering at 6 or 7 in the morning to wait for offers. Their prime ambition is to march in a religious parade or a funeral procession. "Funerals pay NT$200 for an hour or two's work; parades, 500 for five or six. Extras' work is too uncertain. Sometimes you go for 16 hours and get just 300," an unemployed metalworker explains methodically.

What does it take to be an extra? "Nothing special, just strength and patience," says one. There is a lot of waiting involved--for the weather to clear, for props to be found, for the star to arrive, for endless retakes. . . .

And extras must sometimes make sacrifices "in the name of art." When Shaolin kungfu movies were at the peak of their popularity 10 years ago, a hundred monks might be needed in one picture. The casting director had to rely on his powers of persuasion to talk people into shaving their heads. Nobody likes being bald, but when the extras saw that by going "topless" they could have a chance at two or three weeks' work, they grit their teeth and went to the barber. Now it takes three or four months to grow back a full head of hair. But film companies, intent on efficiency, might work round the clock and finish the monk scenes in a couple of days--a bald head for two days' pay.

Then there is the problem of playing a corpse. What could feel more unlucky? But martial arts movies are full of scenes where two rivals clash, swords flash, and three or four hapless underlings go down dead. And scenes with bodies in coffins are not uncommon in historical costume dramas. An extra may curse under his breath, but all he can do in the end is repress his anger and climb in.

"The big stars get a red envelope full of cash to calm their nerves, but for us," one extra says, "don't even think of it!" Extras do not have the privilege of being fussy. "But we're not big stars either. Sometimes I think how making a movie lying down is, at any rate, easier than making one walking around. You've just got to look at the bright side."

Extras may not leave much of an impression on the audience, but, if all the world's a stage, who is to say they aren't real actors, too?