High-Def FAQ: Uncompressed vs. Lossless Audio

Joshu Zyber writes, "A couple of months ago, I wrote a column called Blu-ray and HD DVD Audio Explained that spelled out the basic functions, features, and differences among the various audio formats available on both High-Def disc types. In it, I explained that uncompressed PCM audio (as found on many Blu-rays) is an exact replication of the studio master, encoded on disc without compression, and that the lossless audio formats Dolby TrueHD and DTS-HD Master Audio are also bit-for-bit identical to the studio master once decoded. Doing the math, that should mean that a lossless track is also identical to an uncompressed track. Indeed, that is the case. However, some confusion remains as to whether an uncompressed track is actually better than a lossless one."

"The number of new audio formats on Blu-ray and HD DVD have caused a great deal of consumer confusion, especially with three separate formats (PCM, Dolby TrueHD, and DTS-HD Master Audio) all designed to accomplish the exact same goal — a perfect replication of the movie’s audio master. Apprehensions about lossless compression being inferior to an uncompressed version of the same soundtrack are not borne out by the facts. One methodology may have technical advantages over the other in terms of space savings, but the end result is the same whether the disc you buy has an uncompressed soundtrack or a lossless one. They’re both equally good, so sit back and enjoy."