Decisive price cuts are helping to lift sales of LCD flat-panel TVs after Thanksgiving, research firm iSuppli Corp. said in a new report.

ISuppli said promotional prices are 22 percent lower than before Black Friday, the traditional start of the holiday shopping season. ISuppli estimates 6 percent more TV sets will be sold during a seven-day period that began on Black Friday compared with the same period last year.

The average advertised Black Friday price for a 32-inch set was $369, down from $490 before Thanksgiving.

Prices for larger sets were down more modestly, about 7 percent. Manufacturers instead packed better features into the models that went on sale, such as faster refresh rates for a steadier picture, iSuppli said.

Big brands like Samsung Electronics Co., LG Electronics Inc. and Sony Corp. offered the biggest discounts because they have had the highest regular prices, according to iSuppli analyst Tina Tseng.

ISuppli’s analysis excludes plasma TVs, another type of flat panel that’s less popular than LCD-based units.

A power outage at a Corning Inc. factory in Taiwan didn’t cause a shortage of glass for TVs as initially feared, iSuppli noted. The outage occurred in October, after manufacturers had already bought components for the sets that went on sale on Black Friday.