.pcm File — Pulse-Code Modulation Audio

PCM (Pulse-Code Modulation) is the standard method for digitally representing raw analog audio signals. PCM files contain uncompressed, uncontained digital audio samples — just raw numbers representing amplitude values at regular time intervals. Unlike WAV or AIFF which wrap PCM data in a container with headers describing format parameters, raw PCM files contain only the sample data itself, requiring the player to know the sample rate, bit depth, byte order, and channel configuration to interpret the data correctly. PCM is the fundamental digital audio representation used inside virtually every audio format and codec — WAV, AIFF, FLAC, and even lossy codecs decode to PCM for playback. The format was first developed at Bell Labs in the 1930s-40s by Alec Reeves and later refined by Bell Labs engineers in the 1960s for telephone systems. CD audio uses PCM at 16-bit, 44.1 kHz. Professional audio uses 24-bit or 32-bit float at 48, 96, or 192 kHz. Raw PCM files are used in embedded systems, audio hardware interfaces, telephony systems, and situations where container overhead is undesirable.