Talk:Linear pulse-code modulation

message: I don't think the LPCM article should be merged with Pulse Code Modulation.
It is a computer media format, like MPEG, not just a data encoding format.
Readers need to access it in relation to MPEG, not just in relation to PCM.
___ —Preceding unsigned comment added by 67.122.114.28 (talk) 03:02, 19 August 2005 (UTC)
replies: text: I agree -- I'm after a standard, ISO something something -- very much related to computer audio (DLNA specifically) so it's computer-type information that I'm after. —Preceding unsigned comment added by 210.11.153.86 (talk) 09:16, 31 August 2005 (UTC)

text: I support a merge. I don't see much support for LPCM being a distinct file format. The references cited use the term "linear audio" but not "linear PCM". These are generic audio formats and the individule files already have their own articles, e.g. WAV, AIFF, Au file format -—Kvng 13:47, 27 September 2012 (UTC)
thread_title: Merge with Pulse Code Modulation

message: The stub for LPCM was taken from an ad for a computer program from the company Cyberlink. This is the website:
http://www.cyberlink.com/english/dv-entertainment/articles/lpcm.jsp
—Preceding unsigned comment added by 65.87.26.127 (talk) 17:31, 28 September 2006 (UTC)
thread_title:  Source of the LPCM stub 

message: I think this article should explain the difference between PCM and LPCM.
— Preceding unsigned comment added by Joachim Michaelis (talk • contribs) 08:30, 25 October 2006 (UTC)
thread_title:  vs. PCM 

message: "Most DVD players only support 48 kHz/16-bit capability. Only more high-end players have built-in 96 kHz/24-bit capabilities." is not correct. The official allowed formats for the PCM audio tracks on a DVD Video are:
 * PCM: 48 kHz or 96 kHz sampling rate, 16 bit or 24 bit L-PCM, 2 to 6 channels, up to 6144 kbit/s
This means that there has to be a 24 bit decoder. But probably only with 16 bit accuracy in reallity. (8 bit of noise at the LSB)
But I'm not absolutely sure.
--helohe (talk) 16:19, 21 April 2007 (UTC)
thread_title:  Most DVD players only support 48 kHz/16-bit capability. Only more high-end players have built-in 96 kHz/24-bit capabilities.  

message: Quote from the article:
Standard sampling resolutions and rates</br>
Common sample resolutions for LPCM are 8, 16, 20 or 24 bits per sample. 
While two channels (stereo) is the most common format, some can support up to 8 audio channels (7.1 surround).
Common sampling frequencies are 48 kHz as used with DVD format videos, or 44.1 kHz as used in compact discs. Sampling frequencies of 96 kHz or 192 kHz can be used on some newer equipment, with the higher value equating to 6.144 megabits per second per audio channel.
It seems to me that the 6.144 mbps figure is arrived at by multiplying 192 kHz and 32 bits.
This gets you 6144000 bits per second.  It is not clear that 32 bit samples were used in this calculation, especially since it isn't listed in the list of common sample resolutions.
Furthermore, 6144000 bps is equal to 5.859375 mbps, not 6.144 mbps.
It is unfortunate that the example used here is so similar to the max bitrate for PCM tracks on a DVD - 6144 kbps.
—Preceding unsigned comment added by 128.111.117.22 (talk) 16:04, 13 May 2008 (UTC)
thread_title:  Sampling Resolution and Rates 

message: The article said this:
Theoretically, there is no loss or error in conversion and reconstruction, as long as the sampling rate is just over twice the highest desired frequency component of the recorded signal [Claude Shannon; Harry Nyquist]. For example, if you want to record audio at up to 20 kHz, you would need a frequence of sampling (F/s) of a little more than 40 kHz.
But this is wrong. The Nyquist Theorem says that the highest frequency of signal that CAN be recorded is 1/2 the sampling rate. It does not say that a sampling rate of R will accurately record a signal of frequency R/2. For example, to accurately record a frequency of, say, 22 kHz with a 44 kHz signal requires that the samples be taken at exactly the maximum of the peak and exactly the minimum of the valleys; if the 22 kHz signal is phase-shifted at all from the period of the sampling, then the 22 kHz will be aliased as a lower-frequency signal by the 44 kHz model.  —Preceding unsigned comment added by MarkRLindsey (talk • contribs) 01:06, 2 February 2009 (UTC)
thread_title:  Incorrect Shannon Theory Claim 

message: The article sais If the sample is 16-bit signed, the sample range is from -32768 to 32767, with a centerpoint of 0. If the entire range [-2^{N-1}, 2^{N-1}-1] is allowed, then the zero value actually is (assuming the zero value is the average of maximum and minimum)
\frac{-2^{N-1} + 2^{N-1}-1}{2} = 2^N\frac{-2^{-1} + 2^{-1}-2^{-N}}{2}=-2^N 2^{-N}/2=-1/2\neq 0
—Preceding unsigned comment added by 90.229.142.67 (talk) 14:09, 31 December 2010 (UTC)
thread_title:  Zero value in signed code

message: This article says that "LPCM is PCM with linear quantization". However, there is no such thing as linear quantization. Quantization is an inherently non-linear process.  Linear processes are (ordinarily) invertible. Quantization is not invertible. No quantizer is linear. Some abuse of basic mathematical concepts is necessary to come up with such a term.  This strange term "linear quantization" should be removed, or at least explained. The referenced document does not provide a definition of this self-contradictory term. —SudoMonas (talk) 16:51, 25 April 2011 (UTC)
replies: text: Linear here refers to the step size use for encoding. An example on non-linear PCM is something encoded using Mu-law. -—Kvng 13:47, 27 September 2012 (UTC)
thread_title: Strictly speaking, the term "linear quantization" is self-contradictory