Video Asylum

Posted by Joe Murphy Jr (A) on June 30, 2011 at 15:12:54

In Reply to: RE: wow, you know your stuff! posted by centaurus3200 on June 30, 2011 at 14:30:17

The great majority of laserdiscs have digital audio tracks encoded at CD's standard of 16/44. In the early days of laserdiscs, however, the tracks were analog only. Later, as surround sound became more prominent in movies, laserdiscs adopted Dolby AC-3 (the early name for Dolby Digital's lossy format). However, an RF output was needed to make use of the surround tracks and the addition of the AC-3 tracks did away with the right channel analog track. Then, toward the "end", DTS was able to get some laserdiscs encoded in their surround format. For DTS' laserdiscs, they did away with the digital PCM tracks (both analog tracks remained).

Today, the majority of Blu-ray movies are encoded with DTS-HD Master Audio. This is a lossless format which, once decompressed, is equivalent to uncompressed PCM. The common bit depth and sample rate is 24/48, though there were some movies which were put on disc as 16-bit. The 48kHz sample rate is the movie industry's standard: some concerts have 96kHz tracks. The first couple of years saw Blu-ray encoded with uncompressed PCM, Dolby Digital (lossy), Dolby TrueHD (Dolby's lossless format) and DTS (lossy).