wFormatTag

wFormatTag is a data type used in the Microsoft Windows API, particularly within the context of audio data structures such as WAVEFORMATEX and WAVEFORMATEXTENSIBLE. It specifies the audio format tag, which identifies the encoding or compression used for a waveform audio format.

The value of wFormatTag is a 16-bit unsigned integer that indicates the format of the audio data. Common format tags include PCM (Pulse Code Modulation), indicated by the value 1, which is the standard uncompressed audio format. Other format tags represent various compressed and specialized formats, such as IEEE float, A-law, μ-law, and proprietary formats.

The wFormatTag field is a critical component of audio format descriptors, as it informs the multimedia subsystem how to interpret the raw audio data. When configuring audio devices or processing audio streams, the format tag ensures compatibility between hardware, drivers, and applications.

In many Windows programming scenarios, the wFormatTag is part of the WAVEFORMATEX structure, which also includes other parameters like nChannels (number of audio channels), nSamplesPerSec (sample rate), nAvgBytesPerSec, nBlockAlign, and wBitsPerSample. This structure is widely used for defining, communicating, and processing audio formats within the Windows multimedia framework.

Overall, wFormatTag provides a succinct yet essential piece of information linking raw audio data to its encoding scheme, enabling proper playback, recording, and processing of audio content in Windows-based applications.