I have integrated the Rubberband library with ExoPlayer for pitch and tempo adjustments in an Android project. When using the R2 engine, audio looping works smoothly as expected. However, when switching to the R3 engine(OptionEngineFiner) with looping enabled in exoplayer, there is a minor but noticeable pause between the end and the start of the audio file during loop transitions. This behavior does not occur with the R2 engine(OptionEngineFaster) and only affects the R3 engine, leading to an inconsistent looping experience.
Is there anything I am missing with the R3 engine? I have tried the Rubberband demo app, and looping works fine there.
My AudioProcessor code for exoplayer:
rb = RubberBandStretcher(
inputAudioFormat.sampleRate,
inputAudioFormat.channelCount,
RubberBandStretcher.OptionProcessRealTime.or(RubberBandStretcher.OptionEngineFiner).or(RubberBandStretcher.OptionWindowShort).or(RubberBandStretcher.OptionFormantPreserved).or(RubberBandStretcher.OptionPitchHighConsistency),
speed.toDouble(),
pitch.toDouble()
)
Whole code for Audio Processor
class RubberBandAudioProcessor : AudioProcessor {
/** Indicates that the output sample rate should be the same as the input. */
val SAMPLE_RATE_NO_CHANGE = -1
/** The threshold below which the difference between two pitch/speed factors is negligible. */
private val CLOSE_THRESHOLD = 0.0001f
/**
* The minimum number of output bytes required for duration scaling to be calculated using the
* input and output byte counts, rather than using the current playback speed.
*/
private val MIN_BYTES_FOR_DURATION_SCALING_CALCULATION = 1024
private var pendingOutputSampleRate = 0
private var speed = 1f
private var pitch = 1f
private var pendingInputAudioFormat: AudioProcessor.AudioFormat
private var pendingOutputAudioFormat: AudioProcessor.AudioFormat
private var inputAudioFormat: AudioProcessor.AudioFormat
private var outputAudioFormat: AudioProcessor.AudioFormat
private var pendingSonicRecreation = false
private var rb: RubberBandStretcher? = null
private var buffer: ByteBuffer
private var shortBuffer: ShortBuffer
private var outputBuffer: ByteBuffer
private var inputBytes: Long = 0
private var outputBytes: Long = 0
private var inputEnded = false
/** Creates a new Sonic audio processor. */
init {
speed = 1f
pitch = 1f
pendingInputAudioFormat = AudioProcessor.AudioFormat.NOT_SET
pendingOutputAudioFormat = AudioProcessor.AudioFormat.NOT_SET
inputAudioFormat = AudioProcessor.AudioFormat.NOT_SET
outputAudioFormat = AudioProcessor.AudioFormat.NOT_SET
buffer = AudioProcessor.EMPTY_BUFFER
shortBuffer = buffer.asShortBuffer()
outputBuffer = AudioProcessor.EMPTY_BUFFER
pendingOutputSampleRate = SAMPLE_RATE_NO_CHANGE
}
/**
* Sets the target playback speed. This method may only be called after draining data through the
* processor. The value returned by [.isActive] may change, and the processor must be
* [flushed][.flush] before queueing more data.
*
* @param speed The target factor by which playback should be sped up.
*/
fun setSpeed(speed: Float) {
if (this.speed != speed) {
this.speed = 1/speed
rb?.timeRatio = 1/speed.toDouble()
pendingSonicRecreation = true
}
}
/**
* Sets the target playback pitch. This method may only be called after draining data through the
* processor. The value returned by [.isActive] may change, and the processor must be
* [flushed][.flush] before queueing more data.
*
* @param pitch The target pitch.
*/
fun setPitch(pitch: Float) {
if (this.pitch != pitch) {
this.pitch = pitch
rb?.pitchScale=pitch.toDouble()
pendingSonicRecreation = true
}
}
/**
* Sets the sample rate for output audio, in Hertz. Pass [.SAMPLE_RATE_NO_CHANGE] to output
* audio at the same sample rate as the input. After calling this method, call [ ][.configure] to configure the processor with the new sample rate.
*
* @param sampleRateHz The sample rate for output audio, in Hertz.
* @see .configure
*/
fun setOutputSampleRateHz(sampleRateHz: Int) {
pendingOutputSampleRate = sampleRateHz
}
/**
* Returns the media duration corresponding to the specified playout duration, taking speed
* adjustment into account.
*
*
* The scaling performed by this method will use the actual playback speed achieved by the
* audio processor, on average, since it was last flushed. This may differ very slightly from the
* target playback speed.
*
* @param playoutDuration The playout duration to scale.
* @return The corresponding media duration, in the same units as `duration`.
*/
fun getMediaDuration(playoutDuration: Long): Long {
return if (outputBytes >= MIN_BYTES_FOR_DURATION_SCALING_CALCULATION) {
val processedInputBytes = inputBytes - Assertions.checkNotNull(rb).samplesRequired
if (outputAudioFormat.sampleRate == inputAudioFormat.sampleRate) Util.scaleLargeTimestamp(
playoutDuration,
processedInputBytes,
outputBytes
) else Util.scaleLargeTimestamp(
playoutDuration,
processedInputBytes * outputAudioFormat.sampleRate,
outputBytes * inputAudioFormat.sampleRate
)
} else {
(speed.toDouble() * playoutDuration).toLong()
}
}
@Throws(UnhandledAudioFormatException::class)
override fun configure(inputAudioFormat: AudioProcessor.AudioFormat): AudioProcessor.AudioFormat {
if (inputAudioFormat.encoding != C.ENCODING_PCM_16BIT) {
throw UnhandledAudioFormatException(inputAudioFormat)
}
val outputSampleRateHz =
if (pendingOutputSampleRate == SAMPLE_RATE_NO_CHANGE) inputAudioFormat.sampleRate else pendingOutputSampleRate
pendingInputAudioFormat = inputAudioFormat
pendingOutputAudioFormat = AudioProcessor.AudioFormat(
outputSampleRateHz,
inputAudioFormat.channelCount,
C.ENCODING_PCM_16BIT
)
pendingSonicRecreation = true
return pendingOutputAudioFormat
}
override fun isActive(): Boolean {
val outputSampleRate = pendingOutputAudioFormat.sampleRate
val inputSampleRate = pendingInputAudioFormat.sampleRate
val speedDifference = abs(speed - 1f)
val pitchDifference = abs(pitch - 1f)
val isOutputSampleRateValid = outputSampleRate != Format.NO_VALUE
val isSpeedChanged = speedDifference >= CLOSE_THRESHOLD
val isPitchChanged = pitchDifference >= CLOSE_THRESHOLD
val isSampleRateDifferent = outputSampleRate != inputSampleRate
return (isOutputSampleRateValid
&& (isSpeedChanged || isPitchChanged || isSampleRateDifferent))
}
override fun queueInput(inputBuffer: ByteBuffer) {
if (!inputBuffer.hasRemaining()) {
return
}
val rb = Assertions.checkNotNull(rb)
val shortBuffer = inputBuffer.asShortBuffer()
val inputSize = inputBuffer.remaining()
inputBytes += inputSize.toLong()
rb.process(shortBuffer, inputAudioFormat.channelCount, false)
inputBuffer.position(inputBuffer.position() + inputSize)
}
override fun queueEndOfStream() {
Log.e("RUBBERBANDAUDIOPROCESSOR","QueueEndOfStream");
if (rb != null) {
rb!!.queueEndOfStream()
}
inputEnded = true
}
override fun getOutput(): ByteBuffer {
val rb = rb
val channelCount = inputAudioFormat.channelCount
val samplesRequired = rb?.samplesRequired
if (rb != null) {
val outputSize = rb.available()
if (outputSize > 0) {
if (buffer.capacity() < outputSize * channelCount * 2) {
buffer = ByteBuffer.allocateDirect(outputSize * channelCount * 2)
.order(ByteOrder.nativeOrder())
shortBuffer = buffer.asShortBuffer()
} else {
buffer.clear()
shortBuffer.clear()
}
val retrieved = rb.retrieve(shortBuffer, channelCount)
outputBytes += retrieved.toLong() * channelCount * 2
buffer.limit(retrieved * channelCount * 2)
outputBuffer = buffer
}
}
val outputBuffer = outputBuffer
this.outputBuffer = AudioProcessor.EMPTY_BUFFER
return outputBuffer
}
override fun isEnded(): Boolean {
Log.e("inputeEnded", inputEnded.toString())
Log.e("rb", rb.toString())
val samplesRequired= rb?.samplesRequired
Log.e("rb sample required", samplesRequired.toString())
// return inputEnded && (rb == null || samplesRequired == 0)
return inputEnded
}
override fun flush() {
val isAct=isActive();
Log.e("IsActive", isAct.toString())
if (isAct) {
Log.e("pendingSonicRecreation", pendingSonicRecreation.toString() )
inputAudioFormat = pendingInputAudioFormat
outputAudioFormat = pendingOutputAudioFormat
if (pendingSonicRecreation) {
rb = RubberBandStretcher(
inputAudioFormat.sampleRate,
inputAudioFormat.channelCount,
RubberBandStretcher.OptionProcessRealTime.or(RubberBandStretcher.OptionEngineFiner).or(RubberBandStretcher.OptionWindowShort).or(RubberBandStretcher.OptionFormantPreserved).or(RubberBandStretcher.OptionPitchHighConsistency),
speed.toDouble(),
pitch.toDouble()
)
} else if (rb != null) {
rb!!.reset()
}
}
outputBuffer = AudioProcessor.EMPTY_BUFFER
inputBytes = 0
outputBytes = 0
inputEnded = false
}
override fun reset() {
speed = 1f
pitch = 1f
pendingInputAudioFormat = AudioProcessor.AudioFormat.NOT_SET
pendingOutputAudioFormat = AudioProcessor.AudioFormat.NOT_SET
inputAudioFormat = AudioProcessor.AudioFormat.NOT_SET
outputAudioFormat = AudioProcessor.AudioFormat.NOT_SET
buffer = AudioProcessor.EMPTY_BUFFER
shortBuffer = buffer.asShortBuffer()
outputBuffer = AudioProcessor.EMPTY_BUFFER
pendingOutputSampleRate = SAMPLE_RATE_NO_CHANGE
pendingSonicRecreation = false
rb = null
inputBytes = 0
outputBytes = 0
inputEnded = false
}
}
I have tried changing buffer size.
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