On May 22, 2007 at 10:24, bookaroni said...
PCM is a digital form of an analog signal. Straight
PCM uses a high bitrate. So it is usually compressed.
If compressed too much it will be lossy for sure.
Where are you getting this information from? PCM is UNCOMPRESSED period! Even if the studio mastered a movie at 24/48 (that's 24 bit depth / 48,000 sample rate) and downconverted it (which most do) to 16/48, you would have lower fidelity audio but not compressed.
I believe your confusion lies in the difference between fidelity and compression. Rather than downgrade the 24/48 master audio to lower 16/48 fidelity, some studios have chosen to losslessly pack or "zip" these audio masters with DTS-HD MA or Dolby TrueHD. Once unpacked or "unzipped" by a player or HDMI 1.3 receiver, the resulting output is a 24/48 LPCM track that is bit-for-bit identical to the original studio master.
The main reason to use PCM is because your receiver
has no decoding capability. And that would be a pretty
old receiver as most receivers have some sort of decoding
capability. Such as Dolby Digital or DTS. So if your receiver
is Pro Logic, then yes use PCM.
Unless I'm not understanding something in your explanation, again your information isn't quite correct. We're talking about audio from HD-DVDs. The reason for using an uncompressed PCM audio stream is to allow your HD DVD player to decode the HD audio, convert it to PCM and pass it to your receiver via multi-channel analog or multi-channel on HDMI (1.1, 1.2 or 1.2a).
No offense meant, but Wkipedia isn't a very reputable source. Any article that is published on Wikipedia can be edited by anyone, anytime. Most elementary schools teach their students not to use Wikipedia as a research source.
