This year will be crucial for the new format. Heavy holiday discounting and the natural decline in electronics prices over time have pushed prices for some Blu-ray players under $200, a drop of well more than half in the last few years  and into the realm of affordability for many. At the same time, Blu-ray’s backers, including Sony and the Walt Disney Company, face a growing chorus of skeptics that says the window for a high-definition disc format may be closing fast.

One reason is that discs of all kinds may become obsolete as a new wave of digital media services starts to flow into the living room. On Monday, for example, the Korean television maker LG Electronics plans to announce a new line of high-definition televisions that connect directly to the Internet with no set-top box required. The televisions will be able to play movies and television shows from online video-on-demand services, including Netflix.

“The Blu-ray format is in jeopardy simply because the advent of downloadable HD movies is so close,” said Roger L. Kay, president of Endpoint Technologies Associates. a research and consulting company. “Streaming video from the Internet and other means of direct digital delivery are going to put optical formats out of business entirely over the next few years.”

Blu-ray’s supporters have another view. They say the technology had a breakout year, crowned by the holiday success of “The Dark Knight,” which sold 600,000 Blu-ray copies in one day. They also say that Blu-ray players are selling faster than DVD players did at a comparable time in their emergence.

“What we saw in 2008 was increasing adoption of Blu-ray along with decreasing hardware prices,” said Reed Hastings, the chief executive of Netflix, which has persuaded more than half a million members to pay an extra dollar a month to rent Blu-ray discs. “The window of opportunity for DVD and Blu-ray discs is longer than most people think. But it’s not going to last forever.”