Whether it is an ordinary music lover or a headphone enthusiast, everyone will have a little understanding of common audio coding formats, such as MP3, AAC, WAV, FLAC, DSD and so on. However, if someone suddenly talks to you about the PCM encoding format, some people may be a little confused. So today we will use about one minute to understand the PCM encoding format simply and quickly.
PCM encoding (Pulse Code Modulation) is pulse code modulation, developed in the late 1970s and became the main audio modulation mode for CD and DVD. Its sampling frequency ranges from 44.1kHz to 192kHz, and at its input, a filter needs to be set to restrict only the frequency of 20Hz～22.05kHz to pass, so that it can cover the entire frequency range audible to the human ear (20Hz～20KHz ).
The bit rate (sampling size) of PCM has evolved from 14bit to 16bit, 18bit, 20bit and 24bit; the sampling frequency has evolved from 44.1kHz to 192kHz. Therefore, PCM has become a lossless encoding by convention, because PCM represents the best fidelity level in digital audio. However, because both input and output need to set filters to adjust the frequency, the fidelity of PCM encoded audio will be limited. Common file formats of PCM include WAV, APE and FLAC, all of which are lossless music file formats.
As for the "lossless audio" we most often say, it generally refers to the 16bit/44.1kHz sampling rate file in the traditional CD format. It is known as "lossless compression" because it contains the completeness of 20Hz～22.05kHz. Named for the frequency covering the audible range of the human ear.
Almost all lossy compression formats are compressed and converted from WAV format (its internal encoding is still PCM), and many MP3 devices did not support FLAC, APE, AAC and other formats because they did not support the decompression of these files , But there is no player that does not support the WAV format, because the WAV format itself is a PCM stream.