IAudioCaptureClient interface (audioclient.h)

The IAudioCaptureClient interface enables a client to read input data from a capture endpoint buffer. The client obtains a reference to the IAudioCaptureClient interface on a stream object by calling the IAudioClient::GetService method with parameter riid set to REFIID IID_IAudioCaptureClient.

The methods in this interface manage the movement of data packets that contain capture data. The length of a data packet is expressed as the number of audio frames in the packet. The size of an audio frame is specified by the nBlockAlign member of the WAVEFORMATEX (or WAVEFORMATEXTENSIBLE) structure that the client obtains by calling the IAudioClient::GetMixFormat method. The size in bytes of an audio frame equals the number of channels in the stream multiplied by the sample size per channel. For example, the frame size is four bytes for a stereo (2-channel) stream with 16-bit samples. A packet always contains an integral number of audio frames.

When releasing an IAudioCaptureClient interface instance, the client must call the Release method of the instance from the same thread as the call to IAudioClient::GetService that created the object.

For a code example that uses the IAudioCaptureClient interface, see Capturing a Stream.


The IAudioCaptureClient interface inherits from the IUnknown interface. IAudioCaptureClient also has these types of members:


The IAudioCaptureClient interface has these methods.

Method Description
IAudioCaptureClient::GetBuffer Retrieves a pointer to the next available packet of data in the capture endpoint buffer.
IAudioCaptureClient::GetNextPacketSize The GetNextPacketSize method retrieves the number of frames in the next data packet in the capture endpoint buffer.
IAudioCaptureClient::ReleaseBuffer The ReleaseBuffer method releases the buffer.


Minimum supported client Windows Vista [desktop apps | UWP apps]
Minimum supported server Windows Server 2008 [desktop apps | UWP apps]
Target Platform Windows
Header audioclient.h

See also

Core Audio Interfaces