Crate wasapi

Wasapi bindings for Rust

The aim of this crate is to provide easy and safe access to the Wasapi API for audio playback and capture.

The presented API is all safe Rust, but structs and functions closely follow the original Windows API.

For details on how to use Wasapi, please see the Windows documentation.

Bindings are generated automatically using the windows crate.

Supported functionality

These things have been implemented so far:

• Audio playback and capture
• Shared and exclusive modes
• Event-driven buffering
• Loopback capture
• Notifications for volume change, device disconnect etc

Included examples

Example	Description
playsine	Plays a sine wave in shared mode on the default output device.
playsine_events	Similar to playsine but also listens to notifications.
playnoise_exclusive	Plays white noise in exclusive mode on the default output device. Shows how to handle HRESULT errors.
loopback	Shows how to simultaneously capture and render sound, with separate threads for capture and render.
record	Records audio from the default device, and saves the raw samples to a file.
devices	Lists all available audio devices and displays the default devices.

Structs

• AudioCaptureClient
  Struct wrapping an IAudioCaptureClient.
• AudioClient
  Struct wrapping an IAudioClient.
• AudioClock
  Struct wrapping an IAudioClock.
• AudioRenderClient
  Struct wrapping an IAudioRenderClient.
• AudioSessionControl
  Struct wrapping an IAudioSessionControl.
• BufferFlags
  Struct representing the _AUDCLNT_BUFFERFLAGS enum values.
• Device
  Struct wrapping an IMMDevice.
• DeviceCollection
  Struct wrapping an IMMDeviceCollection.
• DeviceCollectionIter
  Iterator for DeviceCollection
• EventCallbacks
  A structure holding the callbacks for notifications
• GUID
  A globally unique identifier (GUID) used to identify COM and WinRT interfaces.
• Handle
  Struct wrapping a HANDLE to an Event Object.
• WasapiError
  Error returned by the Wasapi crate.
• WaveFormat
  Struct wrapping a WAVEFORMATEXTENSIBLE format descriptor.

Enums

• DeviceState
  Possible states for an IMMDevice, an enum representing the DEVICE_STATE_XXX constants
• Direction
  Audio direction, playback or capture.
• DisconnectReason
  Reason for session disconnect, an enum representing the DisconnectReasonXxx values of the AudioSessionDisconnectReason enum
• Role
  Wrapper for ERole. Console is the role used by most applications
• SampleType
  Sample type, float or integer
• SessionState
  Possible states for an AudioSessionControl, an enum representing the AudioSessionStateXxx constants
• ShareMode
  Sharemode for device

Functions

• calculate_period_100ns
  Calculate a period in units of 100ns that corresponds to the given number of buffer frames at the given sample rate. See the IAudioClient documentation.
• deinitialize
  Close the COM library on the current thread.
• get_default_device
  Get the default playback or capture device for the console role
• get_default_device_for_role
  Get the default playback or capture device for a specific role
• initialize_mta
  Initializes COM for use by the calling thread for the multi-threaded apartment (MTA).
• initialize_sta
  Initializes COM for use by the calling thread for a single-threaded apartment (STA).
• make_channelmasks
  Return a vector with suggested channel masks for the given number of channels. Used to find a format that a device accepts in exclusive mode. The values are sorted according to how likely they are to be accepted, with the most likely first.
• make_simple_channelmask
  Make a simple channel mask by adding the correct number of bits. Above the 18 channel positions that are defined it returns a zero.