SynthesisCallback
interface SynthesisCallback
| android.speech.tts.SynthesisCallback |
A callback to return speech data synthesized by a text to speech engine. The engine can provide streaming audio by calling start, then audioAvailable until all audio has been provided, then finally done. #error can be called at any stage in the synthesis process to indicate that an error has occurred, but if the call is made after a call to done, it might be discarded. done must be called at the end of synthesis, regardless of errors. All methods can be only called on the synthesis thread.
Summary
| Public methods | |
|---|---|
| abstract Int |
audioAvailable(buffer: ByteArray!, offset: Int, length: Int)The service should call this method when synthesized audio is ready for consumption. |
| abstract Int |
done()The service should call this method when all the synthesized audio for a request has been passed to |
| abstract Unit |
error()The service should call this method if the speech synthesis fails. |
| abstract Unit |
The service should call this method if the speech synthesis fails. |
| abstract Int | |
| abstract Boolean |
Check if |
| abstract Boolean |
Check if |
| open Unit |
rangeStart(markerInFrames: Int, start: Int, end: Int)The service may call this method to provide timing information about the spoken text. |
| abstract Int |
The service should call this when it starts to synthesize audio for this request. |
Public methods
audioAvailable
abstract fun audioAvailable(
buffer: ByteArray!,
offset: Int,
length: Int
): Int
The service should call this method when synthesized audio is ready for consumption.
This method should only be called on the synthesis thread, while in android.speech.tts.TextToSpeechService#onSynthesizeText.
| Parameters | |
|---|---|
buffer |
ByteArray!: The generated audio data. This method will not hold on to buffer, so the caller is free to modify it after this method returns. |
offset |
Int: The offset into buffer where the audio data starts. |
length |
Int: The number of bytes of audio data in buffer. This must be less than or equal to the return value of getMaxBufferSize. |
| Return | |
|---|---|
Int |
android.speech.tts.TextToSpeech#SUCCESS, android.speech.tts.TextToSpeech#ERROR or android.speech.tts.TextToSpeech#STOPPED. |
done
abstract fun done(): Int
The service should call this method when all the synthesized audio for a request has been passed to audioAvailable.
This method should only be called on the synthesis thread, while in android.speech.tts.TextToSpeechService#onSynthesizeText.
This method has to be called if start and/or #error was called.
| Return | |
|---|---|
Int |
android.speech.tts.TextToSpeech#SUCCESS, android.speech.tts.TextToSpeech#ERROR or android.speech.tts.TextToSpeech#STOPPED. |
error
abstract fun error(): Unit
The service should call this method if the speech synthesis fails.
This method should only be called on the synthesis thread, while in android.speech.tts.TextToSpeechService#onSynthesizeText.
error
abstract fun error(errorCode: Int): Unit
The service should call this method if the speech synthesis fails.
This method should only be called on the synthesis thread, while in android.speech.tts.TextToSpeechService#onSynthesizeText.
| Parameters | |
|---|---|
errorCode |
Int: Error code to pass to the client. One of the ERROR_ values from Value is android.speech.tts.TextToSpeech#ERROR_SYNTHESIS, android.speech.tts.TextToSpeech#ERROR_SERVICE, android.speech.tts.TextToSpeech#ERROR_OUTPUT, android.speech.tts.TextToSpeech#ERROR_NETWORK, android.speech.tts.TextToSpeech#ERROR_NETWORK_TIMEOUT, android.speech.tts.TextToSpeech#ERROR_INVALID_REQUEST, or android.speech.tts.TextToSpeech#ERROR_NOT_INSTALLED_YET |
getMaxBufferSize
abstract fun getMaxBufferSize(): Int
| Return | |
|---|---|
Int |
the maximum number of bytes that the TTS engine can pass in a single call of audioAvailable. Calls to audioAvailable with data lengths larger than this value will not succeed. |
hasFinished
abstract fun hasFinished(): Boolean
Check if done was called or not.
This method should only be called on the synthesis thread, while in android.speech.tts.TextToSpeechService#onSynthesizeText.
Useful for checking if a fallback from network request is possible.
hasStarted
abstract fun hasStarted(): Boolean
Check if start was called or not.
This method should only be called on the synthesis thread, while in android.speech.tts.TextToSpeechService#onSynthesizeText.
Useful for checking if a fallback from network request is possible.
rangeStart
open fun rangeStart(
markerInFrames: Int,
start: Int,
end: Int
): Unit
The service may call this method to provide timing information about the spoken text.
Calling this method means that at the given audio frame, the given range of the input is about to be spoken. If this method is called the client will receive a callback on the listener (UtteranceProgressListener.onRangeStart) at the moment that frame has been reached by the playback head.
This information can be used by the client, for example, to highlight ranges of the text while it is spoken.
The markerInFrames is a frame index into the audio for this synthesis request, i.e. into the concatenation of the audio bytes sent to audioAvailable for this synthesis request. The definition of a frame depends on the format given by start. See AudioFormat for more information.
This method should only be called on the synthesis thread, while in android.speech.tts.TextToSpeechService#onSynthesizeText.
| Parameters | |
|---|---|
markerInFrames |
Int: The position in frames in the audio where this range is spoken. |
start |
Int: The start index of the range in the input text. |
end |
Int: The end index (exclusive) of the range in the input text. |
start
abstract fun start(
sampleRateInHz: Int,
audioFormat: Int,
channelCount: Int
): Int
The service should call this when it starts to synthesize audio for this request.
This method should only be called on the synthesis thread, while in android.speech.tts.TextToSpeechService#onSynthesizeText.
| Parameters | |
|---|---|
sampleRateInHz |
Int: Sample rate in HZ of the generated audio. |
audioFormat |
Int: Audio format of the generated audio. Must be one of android.media.AudioFormat#ENCODING_PCM_8BIT or AudioFormat.ENCODING_PCM_16BIT. Can also be AudioFormat.ENCODING_PCM_FLOAT when targetting Android N and above. Value is android.media.AudioFormat#ENCODING_PCM_8BIT, android.media.AudioFormat#ENCODING_PCM_16BIT, or android.media.AudioFormat#ENCODING_PCM_FLOAT |
channelCount |
Int: The number of channels. Must be 1 or 2. Value is between 1 and 2 inclusive |
| Return | |
|---|---|
Int |
android.speech.tts.TextToSpeech#SUCCESS, android.speech.tts.TextToSpeech#ERROR or android.speech.tts.TextToSpeech#STOPPED. |