Properties
Result
typedef android.hardware.audio@2.0::Result Result
ReadCommand
enum ReadCommand: int32_t
Commands that can be executed on the driver reader thread.
| Details |
| Members |
READ
|
|
GET_CAPTURE_POSITION
|
|
|
ReadParameters
struct ReadParameters {ReadCommand command; union Params params}
Data structure passed to the driver for executing commands on the driver reader thread.
ReadStatus
struct ReadStatus {Result retval; ReadCommand replyTo; union Reply reply}
Data structure passed back to the client via status message queue of 'read' operation.
Possible values of 'retval' field:- OK, read operation was successful;- INVALID_ARGUMENTS, stream was not configured properly;- INVALID_STATE, stream is in a state that doesn't allow reads.
Methods
getAudioSource
getAudioSource ()
generates (Result retval, AudioSource source)
Returns the source descriptor of the input stream.Calling this method is equivalent to getting AUDIO_PARAMETER_STREAM_INPUT_SOURCE on the legacy HAL.
| Details |
| Generates |
retval
|
operation completion status.
|
source
|
audio source.
|
|
setGain
setGain (float gain)
generates (Result retval)
Set the input gain for the audio driver.
| Details |
| Parameters |
gain
|
1.0f is unity, 0.0f is zero .@result retval operation completion status.
|
|
| Generates |
|
prepareForReading
prepareForReading (uint32_t frameSize, uint32_t framesCount)
generates (Result retval, fmq_sync<ReadParameters> commandMQ, fmq_sync<uint8_t> dataMQ, fmq_sync<ReadStatus> statusMQ, ThreadInfo threadInfo)
Set up required transports for receiving audio buffers from the driver.
The transport consists of three message queues:-- command queue is used to instruct the reader thread what operation to perform;-- data queue is used for passing audio data from the driver to the client;-- status queue is used for reporting operation status(e.g.amount of bytes actually read or error code).
The driver operates on a dedicated thread.The client must ensure that the thread is given an appropriate priority and assigned to correct scheduler and cgroup.For this purpose, the method returns identifiers of the driver thread.
| Details |
| Parameters |
frameSize
|
the size of a single frame, in bytes.
|
framesCount
|
the number of frames in a buffer.
|
|
| Generates |
retval
|
OK if both message queues were created successfully.INVALID_STATE if the method was already called.INVALID_ARGUMENTS if there was a problem setting up the queues.
|
commandMQ
|
a message queue used for passing commands.
|
dataMQ
|
a message queue used for passing audio data in the format specified at the stream opening.
|
statusMQ
|
a message queue used for passing status from the driver using ReadStatus structures.
|
threadInfo
|
identifiers of the driver's dedicated thread.
|
|
getInputFramesLost
getInputFramesLost ()
generates (uint32_t framesLost)
Return the amount of input frames lost in the audio driver since the last call of this function.
Audio driver is expected to reset the value to 0 and restart counting upon returning the current value by this function call.Such loss typically occurs when the user space process is blocked longer than the capacity of audio driver buffers.
| Details |
| Generates |
framesLost
|
the number of input audio frames lost.
|
|
getCapturePosition
getCapturePosition ()
generates (Result retval, uint64_t frames, uint64_t time)
Return a recent count of the number of audio frames received and the clock time associated with that frame count.
| Details |
| Generates |
retval
|
INVALID_STATE if the device is not ready/available, NOT_SUPPORTED if the command is not supported, OK otherwise.
|
frames
|
the total frame count received.This must be as early in the capture pipeline as possible.In general, frames must be non-negative and must not go "backwards".
|
time
|
is the clock monotonic time when frames was measured.In general, time must be a positive quantity and must not go "backwards".
|
|
