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AudioFormat

public final class AudioFormat
extends Object implements Parcelable

java.lang.Object
↳	android.media.AudioFormat

The AudioFormat class is used to access a number of audio format and channel configuration constants. They are for instance used in AudioTrack and AudioRecord, as valid values in individual parameters of constructors like AudioTrack#AudioTrack(int, int, int, int, int, int), where the fourth parameter is one of the AudioFormat.ENCODING_* constants. The AudioFormat constants are also used in MediaFormat to specify audio related values commonly used in media, such as for MediaFormat#KEY_CHANNEL_MASK.

The AudioFormat.Builder class can be used to create instances of the AudioFormat format class. Refer to AudioFormat.Builder for documentation on the mechanics of the configuration and building of such instances. Here we describe the main concepts that the AudioFormat class allow you to convey in each instance, they are:

sample rate
encoding
channel masks

Closely associated with the AudioFormat is the notion of an audio frame, which is used throughout the documentation to represent the minimum size complete unit of audio data.

Sample rate

Expressed in Hz, the sample rate in an AudioFormat instance expresses the number of audio samples for each channel per second in the content you are playing or recording. It is not the sample rate at which content is rendered or produced. For instance a sound at a media sample rate of 8000Hz can be played on a device operating at a sample rate of 48000Hz; the sample rate conversion is automatically handled by the platform, it will not play at 6x speed.

As of API Build.VERSION_CODES.M, sample rates up to 192kHz are supported for AudioRecord and AudioTrack, with sample rate conversion performed as needed. To improve efficiency and avoid lossy conversions, it is recommended to match the sample rate for AudioRecord and AudioTrack to the endpoint device sample rate, and limit the sample rate to no more than 48kHz unless there are special device capabilities that warrant a higher rate.

Encoding

Audio encoding is used to describe the bit representation of audio data, which can be either linear PCM or compressed audio, such as AC3 or DTS.

For linear PCM, the audio encoding describes the sample size, 8 bits, 16 bits, or 32 bits, and the sample representation, integer or float.

ENCODING_PCM_8BIT: The audio sample is a 8 bit unsigned integer in the range [0, 255], with a 128 offset for zero. This is typically stored as a Java byte in a byte array or ByteBuffer. Since the Java byte is signed, be careful with math operations and conversions as the most significant bit is inverted.
ENCODING_PCM_16BIT: The audio sample is a 16 bit signed integer typically stored as a Java short in a short array, but when the short is stored in a ByteBuffer, it is native endian (as compared to the default Java big endian). The short has full range from [-32768, 32767], and is sometimes interpreted as fixed point Q.15 data.
ENCODING_PCM_FLOAT: Introduced in API Build.VERSION_CODES.LOLLIPOP, this encoding specifies that the audio sample is a 32 bit IEEE single precision float. The sample can be manipulated as a Java float in a float array, though within a ByteBuffer it is stored in native endian byte order. The nominal range of ENCODING_PCM_FLOAT audio data is [-1.0, 1.0]. It is implementation dependent whether the positive maximum of 1.0 is included in the interval. Values outside of the nominal range are clamped before sending to the endpoint device. Beware that the handling of NaN is undefined; subnormals may be treated as zero; and infinities are generally clamped just like other values for AudioTrack – try to avoid infinities because they can easily generate a NaN.
To achieve higher audio bit depth than a signed 16 bit integer short, it is recommended to use ENCODING_PCM_FLOAT for audio capture, processing, and playback. Floats are efficiently manipulated by modern CPUs, have greater precision than 24 bit signed integers, and have greater dynamic range than 32 bit signed integers. AudioRecord as of API Build.VERSION_CODES.M and AudioTrack as of API Build.VERSION_CODES.LOLLIPOP support ENCODING_PCM_FLOAT.

For compressed audio, the encoding specifies the method of compression, for example ENCODING_AC3 and ENCODING_DTS. The compressed audio data is typically stored as bytes in a byte array or ByteBuffer. When a compressed audio encoding is specified for an AudioTrack, it creates a direct (non-mixed) track for output to an endpoint (such as HDMI) capable of decoding the compressed audio. For (most) other endpoints, which are not capable of decoding such compressed audio, you will need to decode the data first, typically by creating a MediaCodec. Alternatively, one may use MediaPlayer for playback of compressed audio files or streams.

When compressed audio is sent out through a direct AudioTrack, it need not be written in exact multiples of the audio access unit; this differs from MediaCodec input buffers.

Channel mask

Channel masks are used in AudioTrack and AudioRecord to describe the samples and their arrangement in the audio frame. They are also used in the endpoint (e.g. a USB audio interface, a DAC connected to headphones) to specify allowable configurations of a particular device.
As of API Build.VERSION_CODES.M, there are two types of channel masks: channel position masks and channel index masks.

Channel position masks

Channel position masks are the original Android channel masks, and are used since API Build.VERSION_CODES.BASE. For input and output, they imply a positional nature - the location of a speaker or a microphone for recording or playback.
For a channel position mask, each allowed channel position corresponds to a bit in the channel mask. If that channel position is present in the audio frame, that bit is set, otherwise it is zero. The order of the bits (from lsb to msb) corresponds to the order of that position's sample in the audio frame.
The canonical channel position masks by channel count are as follows:

channel count	channel position mask
1	`CHANNEL_OUT_MONO`
2	`CHANNEL_OUT_STEREO`
3	`CHANNEL_OUT_STEREO` \| `CHANNEL_OUT_FRONT_CENTER`
4	`CHANNEL_OUT_QUAD`
5	`CHANNEL_OUT_QUAD` \| `CHANNEL_OUT_FRONT_CENTER`
6	`CHANNEL_OUT_5POINT1`
7	`CHANNEL_OUT_5POINT1` \| `CHANNEL_OUT_BACK_CENTER`
8	`CHANNEL_OUT_7POINT1_SURROUND`

These masks are an ORed composite of individual channel masks. For example CHANNEL_OUT_STEREO is composed of CHANNEL_OUT_FRONT_LEFT and CHANNEL_OUT_FRONT_RIGHT.

Channel index masks

Channel index masks are introduced in API Build.VERSION_CODES.M. They allow the selection of a particular channel from the source or sink endpoint by number, i.e. the first channel, the second channel, and so forth. This avoids problems with artificially assigning positions to channels of an endpoint, or figuring what the i^th position bit is within an endpoint's channel position mask etc.
Here's an example where channel index masks address this confusion: dealing with a 4 channel USB device. Using a position mask, and based on the channel count, this would be a CHANNEL_OUT_QUAD device, but really one is only interested in channel 0 through channel 3. The USB device would then have the following individual bit channel masks: CHANNEL_OUT_FRONT_LEFT, CHANNEL_OUT_FRONT_RIGHT, CHANNEL_OUT_BACK_LEFT and CHANNEL_OUT_BACK_RIGHT. But which is channel 0 and which is channel 3?
For a channel index mask, each channel number is represented as a bit in the mask, from the lsb (channel 0) upwards to the msb, numerically this bit value is 1 << channelNumber. A set bit indicates that channel is present in the audio frame, otherwise it is cleared. The order of the bits also correspond to that channel number's sample order in the audio frame.
For the previous 4 channel USB device example, the device would have a channel index mask 0xF. Suppose we wanted to select only the first and the third channels; this would correspond to a channel index mask 0x5 (the first and third bits set). If an AudioTrack uses this channel index mask, the audio frame would consist of two samples, the first sample of each frame routed to channel 0, and the second sample of each frame routed to channel 2. The canonical channel index masks by channel count are given by the formula (1 << channelCount) - 1.

Use cases

Channel position mask for an endpoint: CHANNEL_OUT_FRONT_LEFT, CHANNEL_OUT_FRONT_CENTER, etc. for HDMI home theater purposes.
Channel position mask for an audio stream: Creating an AudioTrack to output movie content, where 5.1 multichannel output is to be written.
Channel index mask for an endpoint: USB devices for which input and output do not correspond to left or right speaker or microphone.
Channel index mask for an audio stream: An AudioRecord may only want the third and fourth audio channels of the endpoint (i.e. the second channel pair), and not care the about position it corresponds to, in which case the channel index mask is 0xC. Multichannel AudioRecord sessions should use channel index masks.

Audio Frame

For linear PCM, an audio frame consists of a set of samples captured at the same time, whose count and channel association are given by the channel mask, and whose sample contents are specified by the encoding. For example, a stereo 16 bit PCM frame consists of two 16 bit linear PCM samples, with a frame size of 4 bytes. For compressed audio, an audio frame may alternately refer to an access unit of compressed data bytes that is logically grouped together for decoding and bitstream access (e.g. MediaCodec), or a single byte of compressed data (e.g. AudioTrack#getBufferSizeInFrames()), or the linear PCM frame result from decoding the compressed data (e.g.AudioTrack#getPlaybackHeadPosition()), depending on the context where audio frame is used. For the purposes of AudioFormat#getFrameSizeInBytes(), a compressed data format returns a frame size of 1 byte.

Summary

Nested classes
`class`	`AudioFormat.Builder` Builder class for `AudioFormat` objects.

Constants
`int`	`CHANNEL_CONFIGURATION_DEFAULT` This constant is deprecated. Use `CHANNEL_OUT_DEFAULT` or `CHANNEL_IN_DEFAULT` instead.
`int`	`CHANNEL_CONFIGURATION_INVALID` This constant is deprecated. Use `CHANNEL_INVALID` instead.
`int`	`CHANNEL_CONFIGURATION_MONO` This constant is deprecated. Use `CHANNEL_OUT_MONO` or `CHANNEL_IN_MONO` instead.
`int`	`CHANNEL_CONFIGURATION_STEREO` This constant is deprecated. Use `CHANNEL_OUT_STEREO` or `CHANNEL_IN_STEREO` instead.
`int`	`CHANNEL_INVALID` Invalid audio channel mask
`int`	`CHANNEL_IN_BACK`
`int`	`CHANNEL_IN_BACK_PROCESSED`
`int`	`CHANNEL_IN_DEFAULT`
`int`	`CHANNEL_IN_FRONT`
`int`	`CHANNEL_IN_FRONT_PROCESSED`
`int`	`CHANNEL_IN_LEFT`
`int`	`CHANNEL_IN_LEFT_PROCESSED`
`int`	`CHANNEL_IN_MONO`
`int`	`CHANNEL_IN_PRESSURE`
`int`	`CHANNEL_IN_RIGHT`
`int`	`CHANNEL_IN_RIGHT_PROCESSED`
`int`	`CHANNEL_IN_STEREO`
`int`	`CHANNEL_IN_VOICE_DNLINK`
`int`	`CHANNEL_IN_VOICE_UPLINK`
`int`	`CHANNEL_IN_X_AXIS`
`int`	`CHANNEL_IN_Y_AXIS`
`int`	`CHANNEL_IN_Z_AXIS`
`int`	`CHANNEL_OUT_5POINT1`
`int`	`CHANNEL_OUT_7POINT1` This constant is deprecated. Not the typical 7.1 surround configuration. Use `CHANNEL_OUT_7POINT1_SURROUND` instead.
`int`	`CHANNEL_OUT_7POINT1_SURROUND`
`int`	`CHANNEL_OUT_BACK_CENTER`
`int`	`CHANNEL_OUT_BACK_LEFT`
`int`	`CHANNEL_OUT_BACK_RIGHT`
`int`	`CHANNEL_OUT_DEFAULT` Default audio channel mask
`int`	`CHANNEL_OUT_FRONT_CENTER`
`int`	`CHANNEL_OUT_FRONT_LEFT`
`int`	`CHANNEL_OUT_FRONT_LEFT_OF_CENTER`
`int`	`CHANNEL_OUT_FRONT_RIGHT`
`int`	`CHANNEL_OUT_FRONT_RIGHT_OF_CENTER`
`int`	`CHANNEL_OUT_LOW_FREQUENCY`
`int`	`CHANNEL_OUT_MONO`
`int`	`CHANNEL_OUT_QUAD`
`int`	`CHANNEL_OUT_SIDE_LEFT`
`int`	`CHANNEL_OUT_SIDE_RIGHT`
`int`	`CHANNEL_OUT_STEREO`
`int`	`CHANNEL_OUT_SURROUND`
`int`	`ENCODING_AAC_ELD` Audio data format: AAC ELD compressed
`int`	`ENCODING_AAC_HE_V1` Audio data format: AAC HE V1 compressed
`int`	`ENCODING_AAC_HE_V2` Audio data format: AAC HE V2 compressed
`int`	`ENCODING_AAC_LC` Audio data format: AAC LC compressed
`int`	`ENCODING_AAC_XHE` Audio data format: AAC xHE compressed
`int`	`ENCODING_AC3` Audio data format: AC-3 compressed, also known as Dolby Digital
`int`	`ENCODING_AC4` Audio data format: AC-4 sync frame transport format
`int`	`ENCODING_DEFAULT` Default audio data format
`int`	`ENCODING_DOLBY_MAT` Audio data format: Dolby MAT (Metadata-enhanced Audio Transmission) Dolby MAT bitstreams are used to transmit Dolby TrueHD, channel-based PCM, or PCM with metadata (object audio) over HDMI (e.g. Dolby Atmos content).
`int`	`ENCODING_DOLBY_TRUEHD` Audio data format: DOLBY TRUEHD compressed
`int`	`ENCODING_DTS` Audio data format: DTS compressed
`int`	`ENCODING_DTS_HD` Audio data format: DTS HD compressed
`int`	`ENCODING_E_AC3` Audio data format: E-AC-3 compressed, also known as Dolby Digital Plus or DD+
`int`	`ENCODING_E_AC3_JOC` Audio data format: E-AC-3-JOC compressed E-AC-3-JOC streams can be decoded by downstream devices supporting `ENCODING_E_AC3`.
`int`	`ENCODING_IEC61937` Audio data format: compressed audio wrapped in PCM for HDMI or S/PDIF passthrough.
`int`	`ENCODING_INVALID` Invalid audio data format
`int`	`ENCODING_MP3` Audio data format: MP3 compressed
`int`	`ENCODING_OPUS` Audio data format: OPUS compressed.
`int`	`ENCODING_PCM_16BIT` Audio data format: PCM 16 bit per sample.
`int`	`ENCODING_PCM_8BIT` Audio data format: PCM 8 bit per sample.
`int`	`ENCODING_PCM_FLOAT` Audio data format: single-precision floating-point per sample
`int`	`SAMPLE_RATE_UNSPECIFIED` Sample rate will be a route-dependent value.

Inherited constants

From interface android.os.Parcelable

`int`	`CONTENTS_FILE_DESCRIPTOR` Descriptor bit used with `describeContents()`: indicates that the Parcelable object's flattened representation includes a file descriptor.
`int`	`PARCELABLE_WRITE_RETURN_VALUE` Flag for use with `writeToParcel(Parcel, int)`: the object being written is a return value, that is the result of a function such as "`Parcelable someFunction()`", "`void someFunction(out Parcelable)`", or "`void someFunction(inout Parcelable)`".

Fields
`public static final Creator<AudioFormat>`	`CREATOR`

Public methods
`int`	`describeContents()` Describe the kinds of special objects contained in this Parcelable instance's marshaled representation.
`boolean`	`equals(Object o)` Indicates whether some other object is "equal to" this one.
`int`	`getChannelCount()` Return the channel count.
`int`	`getChannelIndexMask()` Return the channel index mask.
`int`	`getChannelMask()` Return the channel mask.
`int`	`getEncoding()` Return the encoding.
`int`	`getFrameSizeInBytes()` Return the frame size in bytes.
`int`	`getSampleRate()` Return the sample rate.
`int`	`hashCode()` Returns a hash code value for the object.
`String`	`toString()` Returns a string representation of the object.
`void`	`writeToParcel(Parcel dest, int flags)` Flatten this object in to a Parcel.

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 timeout, int nanos)` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
`final void`	`wait(long timeout)` Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.
`final void`	`wait()` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.

From interface


        
          android.os.Parcelable

`abstract int`	`describeContents()` Describe the kinds of special objects contained in this Parcelable instance's marshaled representation.
`abstract void`	`writeToParcel(Parcel dest, int flags)` Flatten this object in to a Parcel.

Constants

CHANNEL_CONFIGURATION_DEFAULT

public static final int CHANNEL_CONFIGURATION_DEFAULT

This constant is deprecated.
Use CHANNEL_OUT_DEFAULT or CHANNEL_IN_DEFAULT instead.

Constant Value: 1 (0x00000001)

CHANNEL_CONFIGURATION_INVALID

public static final int CHANNEL_CONFIGURATION_INVALID

This constant is deprecated.
Use CHANNEL_INVALID instead.

Constant Value: 0 (0x00000000)

CHANNEL_CONFIGURATION_MONO

public static final int CHANNEL_CONFIGURATION_MONO

This constant is deprecated.
Use CHANNEL_OUT_MONO or CHANNEL_IN_MONO instead.

Constant Value: 2 (0x00000002)

CHANNEL_CONFIGURATION_STEREO

public static final int CHANNEL_CONFIGURATION_STEREO

This constant is deprecated.
Use CHANNEL_OUT_STEREO or CHANNEL_IN_STEREO instead.

Constant Value: 3 (0x00000003)

CHANNEL_INVALID

public static final int CHANNEL_INVALID

Invalid audio channel mask

Constant Value: 0 (0x00000000)

CHANNEL_IN_BACK

public static final int CHANNEL_IN_BACK

Constant Value: 32 (0x00000020)

CHANNEL_IN_BACK_PROCESSED

public static final int CHANNEL_IN_BACK_PROCESSED

Constant Value: 512 (0x00000200)

CHANNEL_IN_DEFAULT

public static final int CHANNEL_IN_DEFAULT

Constant Value: 1 (0x00000001)

CHANNEL_IN_FRONT

public static final int CHANNEL_IN_FRONT

Constant Value: 16 (0x00000010)

CHANNEL_IN_FRONT_PROCESSED

public static final int CHANNEL_IN_FRONT_PROCESSED

Constant Value: 256 (0x00000100)

CHANNEL_IN_LEFT

public static final int CHANNEL_IN_LEFT

Constant Value: 4 (0x00000004)

CHANNEL_IN_LEFT_PROCESSED

public static final int CHANNEL_IN_LEFT_PROCESSED

Constant Value: 64 (0x00000040)

CHANNEL_IN_MONO

public static final int CHANNEL_IN_MONO

Constant Value: 16 (0x00000010)

CHANNEL_IN_PRESSURE

public static final int CHANNEL_IN_PRESSURE

Constant Value: 1024 (0x00000400)

CHANNEL_IN_RIGHT

public static final int CHANNEL_IN_RIGHT

Constant Value: 8 (0x00000008)

CHANNEL_IN_RIGHT_PROCESSED

public static final int CHANNEL_IN_RIGHT_PROCESSED

Constant Value: 128 (0x00000080)

CHANNEL_IN_STEREO

public static final int CHANNEL_IN_STEREO

Constant Value: 12 (0x0000000c)

CHANNEL_IN_VOICE_DNLINK

public static final int CHANNEL_IN_VOICE_DNLINK

Constant Value: 32768 (0x00008000)

CHANNEL_IN_VOICE_UPLINK

public static final int CHANNEL_IN_VOICE_UPLINK

Constant Value: 16384 (0x00004000)

CHANNEL_IN_X_AXIS

public static final int CHANNEL_IN_X_AXIS

Constant Value: 2048 (0x00000800)

CHANNEL_IN_Y_AXIS

public static final int CHANNEL_IN_Y_AXIS

Constant Value: 4096 (0x00001000)

CHANNEL_IN_Z_AXIS

public static final int CHANNEL_IN_Z_AXIS

Constant Value: 8192 (0x00002000)

CHANNEL_OUT_5POINT1

public static final int CHANNEL_OUT_5POINT1

Constant Value: 252 (0x000000fc)

CHANNEL_OUT_7POINT1

public static final int CHANNEL_OUT_7POINT1

This constant is deprecated.
Not the typical 7.1 surround configuration. Use CHANNEL_OUT_7POINT1_SURROUND instead.

Constant Value: 1020 (0x000003fc)

CHANNEL_OUT_7POINT1_SURROUND

public static final int CHANNEL_OUT_7POINT1_SURROUND

Constant Value: 6396 (0x000018fc)

CHANNEL_OUT_BACK_CENTER

public static final int CHANNEL_OUT_BACK_CENTER

Constant Value: 1024 (0x00000400)

CHANNEL_OUT_BACK_LEFT

public static final int CHANNEL_OUT_BACK_LEFT

Constant Value: 64 (0x00000040)

CHANNEL_OUT_BACK_RIGHT

public static final int CHANNEL_OUT_BACK_RIGHT

Constant Value: 128 (0x00000080)

CHANNEL_OUT_DEFAULT

public static final int CHANNEL_OUT_DEFAULT

Default audio channel mask

Constant Value: 1 (0x00000001)

CHANNEL_OUT_FRONT_CENTER

public static final int CHANNEL_OUT_FRONT_CENTER

Constant Value: 16 (0x00000010)

CHANNEL_OUT_FRONT_LEFT

public static final int CHANNEL_OUT_FRONT_LEFT

Constant Value: 4 (0x00000004)

CHANNEL_OUT_FRONT_LEFT_OF_CENTER

public static final int CHANNEL_OUT_FRONT_LEFT_OF_CENTER

Constant Value: 256 (0x00000100)

CHANNEL_OUT_FRONT_RIGHT

public static final int CHANNEL_OUT_FRONT_RIGHT

Constant Value: 8 (0x00000008)

CHANNEL_OUT_FRONT_RIGHT_OF_CENTER

public static final int CHANNEL_OUT_FRONT_RIGHT_OF_CENTER

Constant Value: 512 (0x00000200)

CHANNEL_OUT_LOW_FREQUENCY

public static final int CHANNEL_OUT_LOW_FREQUENCY

Constant Value: 32 (0x00000020)

CHANNEL_OUT_MONO

public static final int CHANNEL_OUT_MONO

Constant Value: 4 (0x00000004)

CHANNEL_OUT_QUAD

public static final int CHANNEL_OUT_QUAD

Constant Value: 204 (0x000000cc)

CHANNEL_OUT_SIDE_LEFT

public static final int CHANNEL_OUT_SIDE_LEFT

Constant Value: 2048 (0x00000800)

CHANNEL_OUT_SIDE_RIGHT

public static final int CHANNEL_OUT_SIDE_RIGHT

Constant Value: 4096 (0x00001000)

CHANNEL_OUT_STEREO

public static final int CHANNEL_OUT_STEREO

Constant Value: 12 (0x0000000c)

CHANNEL_OUT_SURROUND

public static final int CHANNEL_OUT_SURROUND

Constant Value: 1052 (0x0000041c)

ENCODING_AAC_ELD

public static final int ENCODING_AAC_ELD

Audio data format: AAC ELD compressed

Constant Value: 15 (0x0000000f)

ENCODING_AAC_HE_V1

public static final int ENCODING_AAC_HE_V1

Audio data format: AAC HE V1 compressed

Constant Value: 11 (0x0000000b)

ENCODING_AAC_HE_V2

public static final int ENCODING_AAC_HE_V2

Audio data format: AAC HE V2 compressed

Constant Value: 12 (0x0000000c)

ENCODING_AAC_LC

public static final int ENCODING_AAC_LC

Audio data format: AAC LC compressed

Constant Value: 10 (0x0000000a)

ENCODING_AAC_XHE

public static final int ENCODING_AAC_XHE

Audio data format: AAC xHE compressed

Constant Value: 16 (0x00000010)

ENCODING_AC3

public static final int ENCODING_AC3

Audio data format: AC-3 compressed, also known as Dolby Digital

Constant Value: 5 (0x00000005)

ENCODING_AC4

public static final int ENCODING_AC4

Audio data format: AC-4 sync frame transport format

Constant Value: 17 (0x00000011)

ENCODING_DEFAULT

public static final int ENCODING_DEFAULT

Default audio data format

Constant Value: 1 (0x00000001)

ENCODING_DOLBY_MAT

public static final int ENCODING_DOLBY_MAT

Audio data format: Dolby MAT (Metadata-enhanced Audio Transmission) Dolby MAT bitstreams are used to transmit Dolby TrueHD, channel-based PCM, or PCM with metadata (object audio) over HDMI (e.g. Dolby Atmos content).

Constant Value: 19 (0x00000013)

ENCODING_DOLBY_TRUEHD

public static final int ENCODING_DOLBY_TRUEHD

Audio data format: DOLBY TRUEHD compressed

Constant Value: 14 (0x0000000e)

ENCODING_DTS

public static final int ENCODING_DTS

Audio data format: DTS compressed

Constant Value: 7 (0x00000007)

ENCODING_DTS_HD

public static final int ENCODING_DTS_HD

Audio data format: DTS HD compressed

Constant Value: 8 (0x00000008)

ENCODING_E_AC3

public static final int ENCODING_E_AC3

Audio data format: E-AC-3 compressed, also known as Dolby Digital Plus or DD+

Constant Value: 6 (0x00000006)

ENCODING_E_AC3_JOC

public static final int ENCODING_E_AC3_JOC

Audio data format: E-AC-3-JOC compressed E-AC-3-JOC streams can be decoded by downstream devices supporting ENCODING_E_AC3. Use ENCODING_E_AC3 as the AudioTrack encoding when the downstream device supports ENCODING_E_AC3 but not ENCODING_E_AC3_JOC.

Constant Value: 18 (0x00000012)

ENCODING_IEC61937

public static final int ENCODING_IEC61937

Audio data format: compressed audio wrapped in PCM for HDMI or S/PDIF passthrough. IEC61937 uses a stereo stream of 16-bit samples as the wrapper. So the channel mask for the track must be CHANNEL_OUT_STEREO. Data should be written to the stream in a short[] array. If the data is written in a byte[] array then there may be endian problems on some platforms when converting to short internally.

Constant Value: 13 (0x0000000d)

ENCODING_INVALID

public static final int ENCODING_INVALID

Invalid audio data format

Constant Value: 0 (0x00000000)

ENCODING_MP3

public static final int ENCODING_MP3

Audio data format: MP3 compressed

Constant Value: 9 (0x00000009)

ENCODING_OPUS

public static final int ENCODING_OPUS

Audio data format: OPUS compressed.

Constant Value: 20 (0x00000014)

ENCODING_PCM_16BIT

public static final int ENCODING_PCM_16BIT

Audio data format: PCM 16 bit per sample. Guaranteed to be supported by devices.

Constant Value: 2 (0x00000002)

ENCODING_PCM_8BIT

public static final int ENCODING_PCM_8BIT

Audio data format: PCM 8 bit per sample. Not guaranteed to be supported by devices.

Constant Value: 3 (0x00000003)

ENCODING_PCM_FLOAT

public static final int ENCODING_PCM_FLOAT

Audio data format: single-precision floating-point per sample

Constant Value: 4 (0x00000004)

SAMPLE_RATE_UNSPECIFIED

public static final int SAMPLE_RATE_UNSPECIFIED

Sample rate will be a route-dependent value. For AudioTrack, it is usually the sink sample rate, and for AudioRecord it is usually the source sample rate.

Constant Value: 0 (0x00000000)

Fields

CREATOR

public static final Creator<AudioFormat> CREATOR

Public methods

describeContents

public int describeContents ()

Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. For example, if the object will include a file descriptor in the output of writeToParcel(android.os.Parcel, int), the return value of this method must include the CONTENTS_FILE_DESCRIPTOR bit.

Returns
`int`	a bitmask indicating the set of special object types marshaled by this Parcelable object instance. Value is either `0` or `CONTENTS_FILE_DESCRIPTOR`

equals

public boolean equals (Object o)

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

It is reflexive: for any non-null reference value x, x.equals(x) should return true.
It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Parameters
`o`	`Object`: the reference object with which to compare.

Returns
`boolean`	`true` if this object is the same as the obj argument; `false` otherwise.

getChannelCount

public int getChannelCount ()

Return the channel count.

Returns
`int`	the channel count derived from the channel position mask or the channel index mask. Zero is returned if both the channel position mask and the channel index mask are not set.

getChannelIndexMask

public int getChannelIndexMask ()

Return the channel index mask. See the section on channel masks for more information about the difference between index-based masks, and position-based masks (as returned by getChannelMask()).

Returns
`int`	one of the values that can be set in `Builder#setChannelIndexMask(int)` or `AudioFormat#CHANNEL_INVALID` if not set or an invalid mask was used.

getChannelMask

public int getChannelMask ()

Return the channel mask. See the section on channel masks for more information about the difference between index-based masks(as returned by getChannelIndexMask()) and the position-based mask returned by this function.

Returns
`int`	one of the values that can be set in `Builder#setChannelMask(int)` or `AudioFormat#CHANNEL_INVALID` if not set.

getEncoding

public int getEncoding ()

Return the encoding. See the section on encodings for more information about the different types of supported audio encoding.

Returns
`int`	one of the values that can be set in `Builder#setEncoding(int)` or `AudioFormat#ENCODING_INVALID` if not set.

getFrameSizeInBytes

public int getFrameSizeInBytes ()

Return the frame size in bytes. For PCM or PCM packed compressed data this is the size of a sample multiplied by the channel count. For all other cases, including invalid/unset channel masks, this will return 1 byte. As an example, a stereo 16-bit PCM format would have a frame size of 4 bytes, an 8 channel float PCM format would have a frame size of 32 bytes, and a compressed data format (not packed in PCM) would have a frame size of 1 byte. Both AudioRecord or AudioTrack process data in multiples of this frame size.

Returns
`int`	The audio frame size in bytes corresponding to the encoding and the channel mask. Value is 1 or greater

getSampleRate

public int getSampleRate ()

Return the sample rate.

Returns
`int`	one of the values that can be set in `Builder#setSampleRate(int)` or `SAMPLE_RATE_UNSPECIFIED` if not set.

hashCode

public int hashCode ()

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

The general contract of hashCode is:

Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java™ programming language.)

Returns
`int`	a hash code value for this object.

toString

public String toString ()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())

Returns
`String`	a string representation of the object.

writeToParcel

public void writeToParcel (Parcel dest, 
                int flags)

Flatten this object in to a Parcel.

Parameters
`dest`	`Parcel`: The Parcel in which the object should be written.
`flags`	`int`: Additional flags about how the object should be written. May be 0 or `Parcelable.PARCELABLE_WRITE_RETURN_VALUE`. Value is either `0` or a combination of `Parcelable.PARCELABLE_WRITE_RETURN_VALUE`, and android.os.Parcelable.PARCELABLE_ELIDE_DUPLICATES

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Results for

AudioFormat

Sample rate

Encoding

Channel mask

Channel position masks

Channel index masks

Use cases

Audio Frame

Summary

Nested classes

Constants

Inherited constants

Fields

Public methods

Inherited methods

Constants

CHANNEL_CONFIGURATION_DEFAULT

CHANNEL_CONFIGURATION_INVALID

CHANNEL_CONFIGURATION_MONO

CHANNEL_CONFIGURATION_STEREO

CHANNEL_INVALID

CHANNEL_IN_BACK

CHANNEL_IN_BACK_PROCESSED

CHANNEL_IN_DEFAULT

CHANNEL_IN_FRONT

CHANNEL_IN_FRONT_PROCESSED

CHANNEL_IN_LEFT

CHANNEL_IN_LEFT_PROCESSED

CHANNEL_IN_MONO

CHANNEL_IN_PRESSURE

CHANNEL_IN_RIGHT

CHANNEL_IN_RIGHT_PROCESSED

CHANNEL_IN_STEREO

CHANNEL_IN_VOICE_DNLINK

CHANNEL_IN_VOICE_UPLINK

CHANNEL_IN_X_AXIS

CHANNEL_IN_Y_AXIS

CHANNEL_IN_Z_AXIS

CHANNEL_OUT_5POINT1

CHANNEL_OUT_7POINT1

CHANNEL_OUT_7POINT1_SURROUND

CHANNEL_OUT_BACK_CENTER

CHANNEL_OUT_BACK_LEFT

CHANNEL_OUT_BACK_RIGHT

CHANNEL_OUT_DEFAULT

CHANNEL_OUT_FRONT_CENTER

CHANNEL_OUT_FRONT_LEFT

CHANNEL_OUT_FRONT_LEFT_OF_CENTER

CHANNEL_OUT_FRONT_RIGHT

CHANNEL_OUT_FRONT_RIGHT_OF_CENTER

CHANNEL_OUT_LOW_FREQUENCY

CHANNEL_OUT_MONO

CHANNEL_OUT_QUAD

CHANNEL_OUT_SIDE_LEFT

CHANNEL_OUT_SIDE_RIGHT

CHANNEL_OUT_STEREO

CHANNEL_OUT_SURROUND

ENCODING_AAC_ELD

ENCODING_AAC_HE_V1

ENCODING_AAC_HE_V2

ENCODING_AAC_LC

ENCODING_AAC_XHE

ENCODING_AC3

ENCODING_AC4

ENCODING_DEFAULT

ENCODING_DOLBY_MAT

ENCODING_DOLBY_TRUEHD

ENCODING_DTS

ENCODING_DTS_HD

ENCODING_E_AC3

ENCODING_E_AC3_JOC

ENCODING_IEC61937

ENCODING_INVALID

ENCODING_MP3

ENCODING_OPUS

ENCODING_PCM_16BIT

ENCODING_PCM_8BIT