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squtisquti
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Implement Silence Detection
1 parent 6e55582 commit a59eff8

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8 files changed

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-126
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8 files changed

+445
-126
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‎android-wave-recorder/src/main/java/com/github/squti/androidwaverecorder/Calculate.kt

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/*
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* MIT License
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*
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* Copyright (c) 2024 squti
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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package com.github.squti.androidwaverecorder
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import android.media.AudioFormat
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import android.media.AudioRecord
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import java.io.File
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import java.nio.ByteBuffer
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import java.nio.ByteOrder
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internal fun calculateMinBufferSize(waveConfig: WaveConfig): Int {
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return AudioRecord.getMinBufferSize(
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waveConfig.sampleRate,
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waveConfig.channels,
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waveConfig.audioEncoding
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)
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}
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internal fun calculateAmplitude(data: ByteArray, audioFormat: Int): Int {
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return when (audioFormat) {
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AudioFormat.ENCODING_PCM_8BIT -> {
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val scaleFactor = 32767.0 / 255.0
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(data.average().plus(128) * scaleFactor).toInt()
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}
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AudioFormat.ENCODING_PCM_16BIT -> {
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val shortData = ShortArray(data.size / 2)
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ByteBuffer.wrap(data).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shortData)
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shortData.maxOrNull()?.toInt() ?: 0
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}
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AudioFormat.ENCODING_PCM_32BIT -> {
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val intData = IntArray(data.size / 4)
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ByteBuffer.wrap(data).order(ByteOrder.LITTLE_ENDIAN).asIntBuffer().get(intData)
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val maxAmplitude = intData.maxOrNull() ?: 0
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val scaledAmplitude = ((maxAmplitude / Int.MAX_VALUE.toFloat()) * 32768).toInt()
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scaledAmplitude
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}
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else -> throw IllegalArgumentException("Unsupported audio format for encoding $audioFormat")
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}
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}
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internal fun calculateAmplitude(data: FloatArray): Int {
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val maxFloatAmplitude = data.maxOrNull() ?: 0f
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return (maxFloatAmplitude * 32768).toInt()
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}
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internal fun calculateDurationInMillis(data: ByteArray, waveConfig: WaveConfig): Long {
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return when (waveConfig.audioEncoding) {
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AudioFormat.ENCODING_PCM_8BIT -> {
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(data.size / 1 / channelCount(waveConfig.channels) / waveConfig.sampleRate.toFloat() * 1000).toLong()
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}
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AudioFormat.ENCODING_PCM_16BIT -> {
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(data.size / 2 / channelCount(waveConfig.channels) / waveConfig.sampleRate.toFloat() * 1000).toLong()
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}
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AudioFormat.ENCODING_PCM_32BIT -> {
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(data.size / 4 / channelCount(waveConfig.channels) / waveConfig.sampleRate.toFloat() * 1000).toLong()
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}
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else -> throw IllegalArgumentException("Unsupported audio format for encoding ${waveConfig.audioEncoding}")
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}
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}
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internal fun calculateDurationInMillis(data: FloatArray, waveConfig: WaveConfig): Long {
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return (data.size / channelCount(waveConfig.channels) / waveConfig.sampleRate.toFloat() * 1000).toLong()
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}
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internal fun calculateDurationInMillis(audioFile: File, waveConfig: WaveConfig): Long {
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val bytesPerSample = bitPerSample(waveConfig.audioEncoding) / 8
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val totalSamplesRead =
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(audioFile.length() / bytesPerSample) / channelCount(waveConfig.channels)
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return (totalSamplesRead * 1000 / waveConfig.sampleRate)
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}

‎android-wave-recorder/src/main/java/com/github/squti/androidwaverecorder/FileWriter.kt

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/*
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* MIT License
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*
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* Copyright (c) 2024 squti
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19+
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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package com.github.squti.androidwaverecorder
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import java.io.DataOutputStream
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import java.nio.ByteBuffer
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import java.nio.ByteOrder
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import java.util.LinkedList
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internal class FileWriter(private val outputStream: DataOutputStream) {
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fun writeDataToStream(
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lastSkippedData: LinkedList<ByteArray>,
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data: ByteArray
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) {
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if (lastSkippedData.isNotEmpty()) {
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lastSkippedData.forEach { outputStream.write(it) }
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}
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lastSkippedData.clear()
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outputStream.write(data)
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}
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fun writeDataToStream(
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lastSkippedData: LinkedList<FloatArray>,
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data: FloatArray
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) {
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if (lastSkippedData.isNotEmpty()) {
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lastSkippedData.forEach { floatArray ->
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floatArray.forEach {
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val bytes = ByteBuffer.allocate(4).order(ByteOrder.LITTLE_ENDIAN)
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.putFloat(it).array()
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outputStream.write(bytes)
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}
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}
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}
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lastSkippedData.clear()
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data.forEach {
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val bytes =
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ByteBuffer.allocate(4).order(ByteOrder.LITTLE_ENDIAN).putFloat(it)
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.array()
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outputStream.write(bytes)
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}
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}
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}

‎android-wave-recorder/src/main/java/com/github/squti/androidwaverecorder/RecorderState.kt

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package com.github.squti.androidwaverecorder
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enum class RecorderState {
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RECORDING, PAUSE, STOP
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RECORDING, PAUSE, STOP, SKIPPING_SILENCE
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}

‎android-wave-recorder/src/main/java/com/github/squti/androidwaverecorder/SilenceDetectionConfig.kt

Lines changed: 38 additions & 0 deletions
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/*
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* MIT License
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*
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* Copyright (c) 2024 squti
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
7+
* of this software and associated documentation files (the "Software"), to deal
8+
* in the Software without restriction, including without limitation the rights
9+
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10+
* copies of the Software, and to permit persons to whom the Software is
11+
* furnished to do so, subject to the following conditions:
12+
*
13+
* The above copyright notice and this permission notice shall be included in all
14+
* copies or substantial portions of the Software.
15+
*
16+
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17+
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18+
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19+
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20+
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21+
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22+
* SOFTWARE.
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*/
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package com.github.squti.androidwaverecorder
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/**
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* Configuration for silence detection and handling during audio recording.
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*
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* @property [minAmplitudeThreshold] The minimum amplitude level (1 to 32767) considered as non-silent.
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* @property [bufferDurationInMillis] The duration (in milliseconds) of audio data buffered when silence is detected. It captures the last seconds of silence.
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* @property [preSilenceDurationInMillis] The duration (in milliseconds) of audio data recorded before silence is detected. It captures the last seconds leading up to silence.
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*/
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data class SilenceDetectionConfig(
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var minAmplitudeThreshold: Int,
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var bufferDurationInMillis: Long = 2000,
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var preSilenceDurationInMillis: Long = 2000,
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)

‎android-wave-recorder/src/main/java/com/github/squti/androidwaverecorder/WaveConfig.kt

Lines changed: 7 additions & 1 deletion
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@@ -43,5 +43,11 @@ internal fun bitPerSample(audioEncoding: Int) = when (audioEncoding) {
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AudioFormat.ENCODING_PCM_16BIT -> 16
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AudioFormat.ENCODING_PCM_32BIT -> 32
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AudioFormat.ENCODING_PCM_FLOAT -> 32
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else -> 16
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else -> throw IllegalArgumentException("Unsupported audio format for encoding $audioEncoding")
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}
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internal fun channelCount(channels: Int) = when (channels) {
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AudioFormat.CHANNEL_IN_MONO -> 1
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AudioFormat.CHANNEL_IN_STEREO -> 2
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else -> throw IllegalArgumentException("Unsupported audio channel")
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}

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