Added in API level 28

Summary: Nested Classes | Constants | Fields | Methods | Inherited Methods

MicrophoneInfo

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Kotlin |Java

public final class MicrophoneInfo
extends Object

java.lang.Object
↳	android.media.MicrophoneInfo

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Class providing information on a microphone. It indicates the location and orientation of the microphone on the device as well as useful information like frequency response and sensitivity. It can be used by applications implementing special pre processing effects like noise suppression of beam forming that need to know about precise microphone characteristics in order to adapt their algorithms.

Summary

Nested classes
class	MicrophoneInfo.Coordinate3F

Constants
int	CHANNEL_MAPPING_DIRECT The channel contains raw audio from this microphone.
int	CHANNEL_MAPPING_PROCESSED The channel contains processed audio from this microphone and possibly another microphone.
int	DIRECTIONALITY_BI_DIRECTIONAL Microphone directionality type: bi-directional.
int	DIRECTIONALITY_CARDIOID Microphone directionality type: cardioid.
int	DIRECTIONALITY_HYPER_CARDIOID Microphone directionality type: hyper cardioid.
int	DIRECTIONALITY_OMNI Microphone directionality type: omni.
int	DIRECTIONALITY_SUPER_CARDIOID Microphone directionality type: super cardioid.
int	DIRECTIONALITY_UNKNOWN Unknown microphone directionality.
int	GROUP_UNKNOWN Value used for when the group of the microphone is unknown.
int	INDEX_IN_THE_GROUP_UNKNOWN Value used for when the index in the group of the microphone is unknown.
int	LOCATION_MAINBODY A microphone that locate on main body of the device.
int	LOCATION_MAINBODY_MOVABLE A microphone that locate on a movable main body of the device.
int	LOCATION_PERIPHERAL A microphone that locate on a peripheral.
int	LOCATION_UNKNOWN A microphone that the location is unknown.
float	SENSITIVITY_UNKNOWN Value used for when the sensitivity of the microphone is unknown.
float	SPL_UNKNOWN Value used for when the SPL of the microphone is unknown.

Fields
public static final MicrophoneInfo.Coordinate3F	ORIENTATION_UNKNOWN Value used for when the orientation of the microphone is unknown.
public static final MicrophoneInfo.Coordinate3F	POSITION_UNKNOWN Value used for when the position of the microphone is unknown.

Public methods
String	getAddress() Returns The "address" string of the microphone that corresponds to the address returned by AudioDeviceInfo#getAddress()
List<Pair<Integer, Integer>>	getChannelMapping() Returns a Pair list for channel mapping, which indicating how this microphone is used by each channels or a capture stream.
String	getDescription() Returns alphanumeric code that uniquely identifies the device.
int	getDirectionality() Returns the directionality of microphone.
List<Pair<Float, Float>>	getFrequencyResponse() Returns a Pair list of frequency responses.
int	getGroup() Returns A device group id that can be used to group together microphones on the same peripheral, attachments or logical groups.
int	getId() Returns The system unique device ID that corresponds to the id returned by AudioDeviceInfo#getId().
int	getIndexInTheGroup() Returns unique index for device within its group.
int	getLocation() Returns the location of the microphone.
float	getMaxSpl() Returns the level in dB of the maximum SPL supported by the device at 1000Hz.
float	getMinSpl() Returns the level in dB of the minimum SPL that can be registered by the device at 1000Hz.
MicrophoneInfo.Coordinate3F	getOrientation() Returns A Coordinate3F object that represents the orientation of microphone.
MicrophoneInfo.Coordinate3F	getPosition() Returns A Coordinate3F object that represents the geometric location of microphone in meters.
float	getSensitivity() Returns the level in dBFS produced by a 1000Hz tone at 94 dB SPL.
int	getType() Returns the device type identifier of the microphone (e.g AudioDeviceInfo.TYPE_BUILTIN_MIC).

Inherited methods

From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait(long timeoutMillis, int nanos) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait(long timeoutMillis) Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed. final void wait() Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Constants

CHANNEL_MAPPING_DIRECT

Added in API level 28

public static final int CHANNEL_MAPPING_DIRECT

The channel contains raw audio from this microphone.

Constant Value: 1 (0x00000001)

CHANNEL_MAPPING_PROCESSED

Added in API level 28

public static final int CHANNEL_MAPPING_PROCESSED

The channel contains processed audio from this microphone and possibly another microphone.

Constant Value: 2 (0x00000002)

DIRECTIONALITY_BI_DIRECTIONAL

Added in API level 28

public static final int DIRECTIONALITY_BI_DIRECTIONAL

Microphone directionality type: bi-directional.

Constant Value: 2 (0x00000002)

DIRECTIONALITY_CARDIOID

Added in API level 28

public static final int DIRECTIONALITY_CARDIOID

Microphone directionality type: cardioid.

Constant Value: 3 (0x00000003)

DIRECTIONALITY_HYPER_CARDIOID

Added in API level 28

public static final int DIRECTIONALITY_HYPER_CARDIOID

Microphone directionality type: hyper cardioid.

Constant Value: 4 (0x00000004)

DIRECTIONALITY_OMNI

Added in API level 28

public static final int DIRECTIONALITY_OMNI

Microphone directionality type: omni.

Constant Value: 1 (0x00000001)

DIRECTIONALITY_SUPER_CARDIOID

Added in API level 28

public static final int DIRECTIONALITY_SUPER_CARDIOID

Microphone directionality type: super cardioid.

Constant Value: 5 (0x00000005)

DIRECTIONALITY_UNKNOWN

Added in API level 28

public static final int DIRECTIONALITY_UNKNOWN

Unknown microphone directionality.

Constant Value: 0 (0x00000000)

GROUP_UNKNOWN

Added in API level 28

public static final int GROUP_UNKNOWN

Value used for when the group of the microphone is unknown.

Constant Value: -1 (0xffffffff)

INDEX_IN_THE_GROUP_UNKNOWN

Added in API level 28

public static final int INDEX_IN_THE_GROUP_UNKNOWN

Value used for when the index in the group of the microphone is unknown.

Constant Value: -1 (0xffffffff)

LOCATION_MAINBODY

Added in API level 28

public static final int LOCATION_MAINBODY

A microphone that locate on main body of the device.

Constant Value: 1 (0x00000001)

LOCATION_MAINBODY_MOVABLE

Added in API level 28

public static final int LOCATION_MAINBODY_MOVABLE

A microphone that locate on a movable main body of the device.

Constant Value: 2 (0x00000002)

LOCATION_PERIPHERAL

Added in API level 28

public static final int LOCATION_PERIPHERAL

A microphone that locate on a peripheral.

Constant Value: 3 (0x00000003)

LOCATION_UNKNOWN

Added in API level 28

public static final int LOCATION_UNKNOWN

A microphone that the location is unknown.

Constant Value: 0 (0x00000000)

SENSITIVITY_UNKNOWN

Added in API level 28

public static final float SENSITIVITY_UNKNOWN

Value used for when the sensitivity of the microphone is unknown.

Constant Value: -3.4028235E38

SPL_UNKNOWN

Added in API level 28

public static final float SPL_UNKNOWN

Value used for when the SPL of the microphone is unknown. This value could be used when maximum SPL or minimum SPL is unknown.

Constant Value: -3.4028235E38

Fields

ORIENTATION_UNKNOWN

Added in API level 28

public static final MicrophoneInfo.Coordinate3F ORIENTATION_UNKNOWN

Value used for when the orientation of the microphone is unknown.

POSITION_UNKNOWN

Added in API level 28

public static final MicrophoneInfo.Coordinate3F POSITION_UNKNOWN

Value used for when the position of the microphone is unknown.

Public methods

getAddress

Added in API level 28

public String getAddress ()

Returns The "address" string of the microphone that corresponds to the address returned by AudioDeviceInfo#getAddress()

Returns
String	the address of the microphone This value cannot be null.

getChannelMapping

Added in API level 28

public List<Pair<Integer, Integer>> getChannelMapping ()

Returns a Pair list for channel mapping, which indicating how this microphone is used by each channels or a capture stream. For each Pair, the first value is channel index, the second value is channel mapping type, which could be either CHANNEL_MAPPING_DIRECT or CHANNEL_MAPPING_PROCESSED. If a channel has contributions from more than one microphone, it is likely the HAL did some extra processing to combine the sources, but this is to be inferred by the user. Empty list when the MicrophoneInfo is returned by AudioManager.getMicrophones(). At least one entry when the MicrophoneInfo is returned by AudioRecord.getActiveMicrophones().

Returns
List<Pair<Integer, Integer>>	a Pair list for channel mapping

getDescription

Added in API level 28

public String getDescription ()

Returns alphanumeric code that uniquely identifies the device.

Returns
String	the description of the microphone

getDirectionality

Added in API level 28

public int getDirectionality ()

Returns the directionality of microphone. The return value is one of DIRECTIONALITY_UNKNOWN, DIRECTIONALITY_OMNI, DIRECTIONALITY_BI_DIRECTIONAL, DIRECTIONALITY_CARDIOID, DIRECTIONALITY_HYPER_CARDIOID, or DIRECTIONALITY_SUPER_CARDIOID.

Returns
int	the directionality of microphone Value is either 0 or a combination of DIRECTIONALITY_UNKNOWN, DIRECTIONALITY_OMNI, DIRECTIONALITY_BI_DIRECTIONAL, DIRECTIONALITY_CARDIOID, DIRECTIONALITY_HYPER_CARDIOID, and DIRECTIONALITY_SUPER_CARDIOID

getFrequencyResponse

Added in API level 28

public List<Pair<Float, Float>> getFrequencyResponse ()

Returns a Pair list of frequency responses. For every Pair in the list, the first value represents frequency in Hz, and the second value represents response in dB.

Returns
List<Pair<Float, Float>>	the frequency response of the microphone

getGroup

Added in API level 28

public int getGroup ()

Returns A device group id that can be used to group together microphones on the same peripheral, attachments or logical groups. Main body is usually group 0.

Returns
int	the group of the microphone or GROUP_UNKNOWN if the group is unknown

getId

Added in API level 28

public int getId ()

Returns The system unique device ID that corresponds to the id returned by AudioDeviceInfo#getId().

Returns
int	the microphone's id

getIndexInTheGroup

Added in API level 28

public int getIndexInTheGroup ()

Returns unique index for device within its group.

Returns
int	the microphone's index in its group or INDEX_IN_THE_GROUP_UNKNOWN if the index in the group is unknown

getLocation

Added in API level 28

public int getLocation ()

Returns the location of the microphone. The return value is one of LOCATION_UNKNOWN, LOCATION_MAINBODY, LOCATION_MAINBODY_MOVABLE, or LOCATION_PERIPHERAL.

Returns
int	the location of the microphone Value is either 0 or a combination of LOCATION_UNKNOWN, LOCATION_MAINBODY, LOCATION_MAINBODY_MOVABLE, and LOCATION_PERIPHERAL

getMaxSpl

Added in API level 28

public float getMaxSpl ()

Returns the level in dB of the maximum SPL supported by the device at 1000Hz.

Returns
float	the maximum level in dB or SPL_UNKNOWN if maximum SPL is unknown

getMinSpl

Added in API level 28

public float getMinSpl ()

Returns the level in dB of the minimum SPL that can be registered by the device at 1000Hz.

Returns
float	the minimum level in dB or SPL_UNKNOWN if minimum SPL is unknown

getOrientation

Added in API level 28

public MicrophoneInfo.Coordinate3F getOrientation ()

Returns A Coordinate3F object that represents the orientation of microphone. X-axis, Y-axis and Z-axis show as the x, y, z value. The orientation will be normalized such as sqrt(x^2 + y^2 + z^2) equals 1.

Returns
MicrophoneInfo.Coordinate3F	the orientation of the microphone or ORIENTATION_UNKNOWN if orientation is unknown

getPosition

Added in API level 28

public MicrophoneInfo.Coordinate3F getPosition ()

Returns A Coordinate3F object that represents the geometric location of microphone in meters. X-axis, Y-axis and Z-axis show as the x, y, z values. For mobile devices, the axes originate from the bottom-left-back corner of the appliance. In devices with PackageManager.FEATURE_AUTOMOTIVE, axes are defined with respect to the vehicle body frame, originating from the center of the vehicle's rear axle.

Returns
MicrophoneInfo.Coordinate3F	the geometric location of the microphone or POSITION_UNKNOWN if the geometric location is unknown

See also:

• auto axes

getSensitivity

Added in API level 28

public float getSensitivity ()

Returns the level in dBFS produced by a 1000Hz tone at 94 dB SPL.

Returns
float	the sensitivity of the microphone or SENSITIVITY_UNKNOWN if the sensitivity is unknown

getType

Added in API level 28

public int getType ()

Returns the device type identifier of the microphone (e.g AudioDeviceInfo.TYPE_BUILTIN_MIC).

Returns
int	the device type of the microphone