PCM audio (Pulse Code Modulation) is a process that is utilized to convert analog audio signals that are represented by wave forms to digital audio signals which are represented by ones and zeros without neither compression nor loss of information.
Linear pulse-code modulation (LPCM) is a specific type of PCM where the quantization levels are linearly uniform. This is in contrast to PCM encodings where quantization levels vary as a function of amplitude (as with the A-law algorithm or the μ-law algorithm). Though PCM is a more general term, it is often used to describe data encoded as LPCM. Movies and devices often show audio as "LPCM" but sometimes PCM.
A PCM stream has two basic properties that determine the stream's fidelity to the original analog signal: the sampling rate, which is the number of times per second that samples are taken; and the bit depth, which determines the number of possible digital values that can be used to represent each sample.
To get a visual idea of the space taken up by analog and digital audio, compare the size of a vinyl (analog) disc to that of a CD (digital).
- The sampling rate, that is, the number of times per second that samples are taken; and the bit depth.
- Bit depth is the number of bits of information in each sample and determines the number of possible digital values that each sample can take.
PCM is usually contained by .WAV as files for computers/media players, .m2ts for Blu-ray Discs, .VOB for DVDs and .CDA for Audio CDs.
WAV is very popular because uncompressed WAV files are large, so file sharing of WAV files over the Internet is uncommon except among video, music and audio professionals where the uncompressed form has become the most popular of all audio formats and, for most, high speed large bandwidth web connections are commonplace. Many audio and music software manufacturers now favor it as their default file format though others are often supported. The high resolution of the format make it suitable for retaining first generation archived files of high quality, for use on a system where disk space is not a constraint, or in applications such as audio editing where the time involved in compressing and uncompressing data, and the losses in quality of such conversions are a concern.
Blu-ray uses the .m2ts transport stream for audio. There's software like VLC, AVS Video Editor, Apple's Final Cut Pro, Sony Vegas that can read and edit these files. You can convert .WAV files to .m2ts without loss of compression.