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Function USBAudioSetFeature

USBAudioSetFeature sets a feature value of a Feature Unit of an Audio function:

int USBAudioSetFeature(int AudioID, UINT Feature, UINT Channel, int Value);

Parameters

AudioID

Audio ID value previously returned by function USBAudioGetInfo.

Feature

The type of feature to query (see USBAudioGetFeature).

Channel

The audio channel to query. For some features, channel 0 specifies a "master" channel, typically when a single feature value applies to all channels. Other devices/features will support a unique feature value for each implemented audio channel starting at channel index 1. RTUSB-32 defines special value USB_AUDIO_ALL_CHANNELS which causes this finction to attempt to set the feature on all existing channels (including channel 0).

return value

The requested feature value or a negative error code in case of an error. If the audio function does not implement the requested feature/channel, RTU_NOT_AVAIL is returned.

Initially, many USB Audio devices have an invalid or inappropriate volume level. Before an Audio function is used, it is recommnded to set the USB_AUDIO_MUTE feature to 0 and the USB_AUDIO_VOLUME of all channels (e.g. using Channel parameter USB_AUDIO_ALL_CHANNELS) to a defined value.

Please see function USBAudioGetFeature for a list of all supported feature selectors and supported value ranges.

Function USBAudioGetFeature

Function USBAudioPlay