feat: add sample rate preference (#33) (#92)

Aga-C · web-flow · commit 85373dbd677b · 2025-06-09T19:36:27.000+05:30
* Added setting sampling rate (#33) * Fixed PR comments
diff --git a/app/src/main/kotlin/org/fossify/voicerecorder/activities/SettingsActivity.kt b/app/src/main/kotlin/org/fossify/voicerecorder/activities/SettingsActivity.kt
@@ -35,9 +35,13 @@ import org.fossify.voicerecorder.extensions.getAllRecordings
 import org.fossify.voicerecorder.extensions.hasRecordings
 import org.fossify.voicerecorder.extensions.launchFolderPicker
 import org.fossify.voicerecorder.helpers.BITRATES
+import org.fossify.voicerecorder.helpers.DEFAULT_BITRATE
+import org.fossify.voicerecorder.helpers.DEFAULT_SAMPLING_RATE
 import org.fossify.voicerecorder.helpers.EXTENSION_M4A
 import org.fossify.voicerecorder.helpers.EXTENSION_MP3
 import org.fossify.voicerecorder.helpers.EXTENSION_OGG
+import org.fossify.voicerecorder.helpers.SAMPLING_RATES
+import org.fossify.voicerecorder.helpers.SAMPLING_RATE_BITRATE_LIMITS
 import org.fossify.voicerecorder.models.Events
 import org.greenrobot.eventbus.EventBus
 import java.util.Locale
@@ -76,6 +80,7 @@ class SettingsActivity : SimpleActivity() {
         setupSaveRecordingsFolder()
         setupExtension()
         setupBitrate()
+        setupSamplingRate()
         setupAudioSource()
         setupRecordAfterLaunch()
         setupKeepScreenOn()
@@ -202,18 +207,22 @@ class SettingsActivity : SimpleActivity() {
             RadioGroupDialog(this@SettingsActivity, items, config.extension) {
                 config.extension = it as Int
                 binding.settingsExtension.text = config.getExtensionText()
+                adjustBitrate()
+                adjustSamplingRate()
             }
         }
     }
 
     private fun setupBitrate() {
         binding.settingsBitrate.text = getBitrateText(config.bitrate)
         binding.settingsBitrateHolder.setOnClickListener {
-            val items = BITRATES.map { RadioItem(it, getBitrateText(it)) } as ArrayList
+            val items = BITRATES[config.extension]!!
+                .map { RadioItem(it, getBitrateText(it)) } as ArrayList
 
             RadioGroupDialog(this@SettingsActivity, items, config.bitrate) {
                 config.bitrate = it as Int
                 binding.settingsBitrate.text = getBitrateText(config.bitrate)
+                adjustSamplingRate()
             }
         }
     }
@@ -222,6 +231,52 @@ class SettingsActivity : SimpleActivity() {
         return getString(R.string.bitrate_value).format(value / 1000)
     }
 
+    private fun adjustBitrate() {
+        val availableBitrates = BITRATES[config.extension]!!
+        if (!availableBitrates.contains(config.bitrate)) {
+            config.bitrate = DEFAULT_BITRATE
+            binding.settingsBitrate.text = getBitrateText(config.bitrate)
+        }
+    }
+
+    private fun setupSamplingRate() {
+        binding.settingsSamplingRate.text = getSamplingRateText(config.samplingRate)
+        binding.settingsSamplingRateHolder.setOnClickListener {
+            val items = getSamplingRatesArray()
+                .map { RadioItem(it, getSamplingRateText(it)) } as ArrayList
+
+            RadioGroupDialog(this@SettingsActivity, items, config.samplingRate) {
+                config.samplingRate = it as Int
+                binding.settingsSamplingRate.text = getSamplingRateText(config.samplingRate)
+            }
+        }
+    }
+
+    private fun getSamplingRateText(value: Int): String {
+        return getString(R.string.sampling_rate_value).format(value)
+    }
+
+    private fun getSamplingRatesArray(): ArrayList<Int> {
+        val baseRates = SAMPLING_RATES[config.extension]!!
+        val limits = SAMPLING_RATE_BITRATE_LIMITS[config.extension]!!
+        val filteredRates = baseRates.filter {
+            config.bitrate in limits[it]!![0]..limits[it]!![1]
+        } as ArrayList
+        return filteredRates
+    }
+
+    private fun adjustSamplingRate() {
+        val availableSamplingRates = getSamplingRatesArray()
+        if (!availableSamplingRates.contains(config.samplingRate)) {
+            if (availableSamplingRates.contains(DEFAULT_SAMPLING_RATE)) {
+                config.samplingRate = DEFAULT_SAMPLING_RATE
+            } else {
+                config.samplingRate = availableSamplingRates.last()
+            }
+            binding.settingsSamplingRate.text = getSamplingRateText(config.samplingRate)
+        }
+    }
+
     private fun setupRecordAfterLaunch() {
         binding.settingsRecordAfterLaunch.isChecked = config.recordAfterLaunch
         binding.settingsRecordAfterLaunchHolder.setOnClickListener {
diff --git a/app/src/main/kotlin/org/fossify/voicerecorder/helpers/Config.kt b/app/src/main/kotlin/org/fossify/voicerecorder/helpers/Config.kt
@@ -45,6 +45,10 @@ class Config(context: Context) : BaseConfig(context) {
         get() = prefs.getInt(BITRATE, DEFAULT_BITRATE)
         set(bitrate) = prefs.edit().putInt(BITRATE, bitrate).apply()
 
+    var samplingRate: Int
+        get() = prefs.getInt(SAMPLING_RATE, DEFAULT_SAMPLING_RATE)
+        set(samplingRate) = prefs.edit().putInt(SAMPLING_RATE, samplingRate).apply()
+
     var recordAfterLaunch: Boolean
         get() = prefs.getBoolean(RECORD_AFTER_LAUNCH, false)
         set(recordAfterLaunch) = prefs.edit().putBoolean(RECORD_AFTER_LAUNCH, recordAfterLaunch)
diff --git a/app/src/main/kotlin/org/fossify/voicerecorder/helpers/Constants.kt b/app/src/main/kotlin/org/fossify/voicerecorder/helpers/Constants.kt
@@ -14,9 +14,73 @@ const val EXTENSION_M4A = 0
 const val EXTENSION_MP3 = 1
 const val EXTENSION_OGG = 2
 
-val BITRATES = arrayListOf(32000, 64000, 96000, 128000, 160000, 192000, 256000, 320000)
-const val DEFAULT_BITRATE = 192000
-const val SAMPLE_RATE = 48000
+val BITRATES_MP3 = arrayListOf(
+    8000, 16000, 24000, 32000, 64000, 96000, 128000, 160000, 192000, 256000, 320000
+)
+val BITRATES_M4A = arrayListOf(
+    8000, 14000, 24000, 28000, 32000, 64000, 96000, 128000, 160000, 192000, 288000
+)
+val BITRATES_OPUS = arrayListOf(
+    8000, 16000, 24000, 32000, 64000, 96000, 128000, 160000, 192000, 256000, 320000
+)
+val BITRATES = mapOf(
+    EXTENSION_M4A to BITRATES_M4A,
+    EXTENSION_MP3 to BITRATES_MP3,
+    EXTENSION_OGG to BITRATES_OPUS
+)
+const val DEFAULT_BITRATE = 96000
+
+val SAMPLING_RATES_MP3 = arrayListOf(8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000)
+val SAMPLING_RATES_M4A = arrayListOf(11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000)
+val SAMPLING_RATES_OPUS = arrayListOf(8000, 12000, 16000, 24000, 48000)
+val SAMPLING_RATES = mapOf(
+    EXTENSION_M4A to SAMPLING_RATES_M4A,
+    EXTENSION_MP3 to SAMPLING_RATES_MP3,
+    EXTENSION_OGG to SAMPLING_RATES_OPUS
+)
+const val DEFAULT_SAMPLING_RATE = 48000
+
+// sampling rate -> [min bitrate, max bitrate]
+// according to https://redmine.digispot.ru/projects/support-eng/wiki/Recommended_Sampling_Rate_and_Bitrate_Combinations_for_AAC_codec
+val SAMPLING_RATE_BITRATE_LIMITS_M4A = mapOf(
+    11025 to arrayListOf(8000, 15999),
+    12000 to arrayListOf(8000, 15999),
+    16000 to arrayListOf(8000, 31999),
+    22050 to arrayListOf(24000, 31999),
+    24000 to arrayListOf(24000, 31999),
+    32000 to arrayListOf(32000, 160000),
+    44100 to arrayListOf(56000, 160000),
+    48000 to arrayListOf(56000, 288000)
+)
+
+// according to https://svn.code.sf.net/p/lame/svn/trunk/lame/doc/html/detailed.html#b
+val SAMPLING_RATE_BITRATE_LIMITS_MP3 = mapOf(
+    8000 to arrayListOf(8000, 64000),
+    11025 to arrayListOf(8000, 64000),
+    12000 to arrayListOf(8000, 64000),
+    16000 to arrayListOf(8000, 160000),
+    22050 to arrayListOf(8000, 160000),
+    24000 to arrayListOf(8000, 160000),
+    32000 to arrayListOf(32000, 320000),
+    44100 to arrayListOf(32000, 320000),
+    48000 to arrayListOf(32000, 320000)
+)
+
+// OPUS has only recommendations for bitrate, no limits: https://www.rfc-editor.org/rfc/rfc7587#section-3.1.1
+// only minimum value is set according to them
+val SAMPLING_RATE_BITRATE_LIMITS_OPUS = mapOf(
+    8000 to arrayListOf(8000, 320000),
+    12000 to arrayListOf(16000, 320000),
+    16000 to arrayListOf(28000, 320000),
+    24000 to arrayListOf(48000, 320000),
+    48000 to arrayListOf(64000, 320000)
+)
+
+val SAMPLING_RATE_BITRATE_LIMITS = mapOf(
+    EXTENSION_M4A to SAMPLING_RATE_BITRATE_LIMITS_M4A,
+    EXTENSION_MP3 to SAMPLING_RATE_BITRATE_LIMITS_MP3,
+    EXTENSION_OGG to SAMPLING_RATE_BITRATE_LIMITS_OPUS
+)
 
 const val RECORDING_RUNNING = 0
 const val RECORDING_STOPPED = 1
@@ -31,6 +95,7 @@ const val SAVE_RECORDINGS = "save_recordings"
 const val EXTENSION = "extension"
 const val AUDIO_SOURCE = "audio_source"
 const val BITRATE = "bitrate"
+const val SAMPLING_RATE = "sampling_rate"
 const val RECORD_AFTER_LAUNCH = "record_after_launch"
 const val USE_RECYCLE_BIN = "use_recycle_bin"
 const val LAST_RECYCLE_BIN_CHECK = "last_recycle_bin_check"
diff --git a/app/src/main/kotlin/org/fossify/voicerecorder/recorder/MediaRecorderWrapper.kt b/app/src/main/kotlin/org/fossify/voicerecorder/recorder/MediaRecorderWrapper.kt
@@ -5,7 +5,6 @@ import android.content.Context
 import android.media.MediaRecorder
 import android.os.ParcelFileDescriptor
 import org.fossify.voicerecorder.extensions.config
-import org.fossify.voicerecorder.helpers.SAMPLE_RATE
 
 class MediaRecorderWrapper(val context: Context) : Recorder {
 
@@ -15,7 +14,7 @@ class MediaRecorderWrapper(val context: Context) : Recorder {
         setOutputFormat(context.config.getOutputFormat())
         setAudioEncoder(context.config.getAudioEncoder())
         setAudioEncodingBitRate(context.config.bitrate)
-        setAudioSamplingRate(SAMPLE_RATE)
+        setAudioSamplingRate(context.config.samplingRate)
     }
 
     override fun setOutputFile(path: String) {
diff --git a/app/src/main/kotlin/org/fossify/voicerecorder/recorder/Mp3Recorder.kt b/app/src/main/kotlin/org/fossify/voicerecorder/recorder/Mp3Recorder.kt
@@ -10,7 +10,6 @@ import com.naman14.androidlame.LameBuilder
 import org.fossify.commons.extensions.showErrorToast
 import org.fossify.commons.helpers.ensureBackgroundThread
 import org.fossify.voicerecorder.extensions.config
-import org.fossify.voicerecorder.helpers.SAMPLE_RATE
 import java.io.File
 import java.io.FileNotFoundException
 import java.io.FileOutputStream
@@ -29,15 +28,15 @@ class Mp3Recorder(val context: Context) : Recorder {
     private var fileDescriptor: ParcelFileDescriptor? = null
     private var outputStream: FileOutputStream? = null
     private val minBufferSize = AudioRecord.getMinBufferSize(
-        SAMPLE_RATE,
+        context.config.samplingRate,
         AudioFormat.CHANNEL_IN_MONO,
         AudioFormat.ENCODING_PCM_16BIT
     )
 
     @SuppressLint("MissingPermission")
     private val audioRecord = AudioRecord(
         context.config.audioSource,
-        SAMPLE_RATE,
+        context.config.samplingRate,
         AudioFormat.CHANNEL_IN_MONO,
         AudioFormat.ENCODING_PCM_16BIT,
         minBufferSize * 2
@@ -65,9 +64,9 @@ class Mp3Recorder(val context: Context) : Recorder {
         }
 
         androidLame = LameBuilder()
-            .setInSampleRate(SAMPLE_RATE)
+            .setInSampleRate(context.config.samplingRate)
             .setOutBitrate(context.config.bitrate / 1000)
-            .setOutSampleRate(SAMPLE_RATE)
+            .setOutSampleRate(context.config.samplingRate)
             .setOutChannels(1)
             .build()
 
diff --git a/app/src/main/res/layout/activity_settings.xml b/app/src/main/res/layout/activity_settings.xml
@@ -216,6 +216,28 @@
 
             </RelativeLayout>
 
+            <RelativeLayout
+                android:id="@+id/settings_audio_source_holder"
+                style="@style/SettingsHolderTextViewStyle"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content">
+
+                <org.fossify.commons.views.MyTextView
+                    android:id="@+id/settings_audio_source_label"
+                    style="@style/SettingsTextLabelStyle"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="@string/audio_source" />
+
+                <org.fossify.commons.views.MyTextView
+                    android:id="@+id/settings_audio_source"
+                    style="@style/SettingsTextValueStyle"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:layout_below="@+id/settings_audio_source_label"
+                    tools:text="Camera" />
+            </RelativeLayout>
+
             <RelativeLayout
                 android:id="@+id/settings_extension_holder"
                 style="@style/SettingsHolderTextViewStyle"
@@ -240,47 +262,48 @@
             </RelativeLayout>
 
             <RelativeLayout
-                android:id="@+id/settings_audio_source_holder"
+                android:id="@+id/settings_bitrate_holder"
                 style="@style/SettingsHolderTextViewStyle"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content">
 
                 <org.fossify.commons.views.MyTextView
-                    android:id="@+id/settings_audio_source_label"
+                    android:id="@+id/settings_bitrate_label"
                     style="@style/SettingsTextLabelStyle"
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content"
-                    android:text="@string/audio_source" />
+                    android:text="@string/bitrate" />
 
                 <org.fossify.commons.views.MyTextView
-                    android:id="@+id/settings_audio_source"
+                    android:id="@+id/settings_bitrate"
                     style="@style/SettingsTextValueStyle"
                     android:layout_width="match_parent"
                     android:layout_height="wrap_content"
-                    android:layout_below="@+id/settings_audio_source_label"
-                    tools:text="128 kbps" />
+                    android:layout_below="@+id/settings_bitrate_label"
+                    tools:text="192 kbps" />
+
             </RelativeLayout>
 
             <RelativeLayout
-                android:id="@+id/settings_bitrate_holder"
+                android:id="@+id/settings_sampling_rate_holder"
                 style="@style/SettingsHolderTextViewStyle"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content">
 
                 <org.fossify.commons.views.MyTextView
-                    android:id="@+id/settings_bitrate_label"
+                    android:id="@+id/settings_sampling_rate_label"
                     style="@style/SettingsTextLabelStyle"
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content"
-                    android:text="@string/bitrate" />
+                    android:text="@string/sample_rate" />
 
                 <org.fossify.commons.views.MyTextView
-                    android:id="@+id/settings_bitrate"
+                    android:id="@+id/settings_sampling_rate"
                     style="@style/SettingsTextValueStyle"
                     android:layout_width="match_parent"
                     android:layout_height="wrap_content"
-                    android:layout_below="@+id/settings_bitrate_label"
-                    tools:text="192 kbps" />
+                    android:layout_below="@+id/settings_sampling_rate_label"
+                    tools:text="48000 Hz" />
 
             </RelativeLayout>
 
diff --git a/app/src/main/res/values-pl/strings.xml b/app/src/main/res/values-pl/strings.xml
@@ -21,6 +21,7 @@
     <string name="bitrate">Przepływność</string>
     <string name="record_after_launch">Rozpoczynaj nagrywanie automatycznie przy uruchomieniu aplikacji</string>
     <string name="keep_screen_on">Pozostawiaj ekran włączony podczas nagrywania</string>
+    <string name="sample_rate">Częstotliwość próbkowania</string>
     <string name="audio_source_camcorder">Aparat</string>
     <string name="audio_source_default">Domyślne systemowe</string>
     <string name="audio_source_unprocessed">Nieprzetworzone</string>
diff --git a/app/src/main/res/values/donottranslate.xml b/app/src/main/res/values/donottranslate.xml
@@ -7,4 +7,5 @@
     <string name="ogg">ogg</string>
     <string name="ogg_opus">ogg (Opus)</string>
     <string name="bitrate_value">%d kbps</string>
+    <string name="sampling_rate_value">%d Hz</string>
 </resources>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
@@ -28,6 +28,7 @@
     <string name="bitrate">Bitrate</string>
     <string name="record_after_launch">Start recording automatically after launching the app</string>
     <string name="keep_screen_on">Keep the screen on during recording</string>
+    <string name="sample_rate">Sample rate</string>
     <!-- Settings Audio source selection -->
     <string name="audio_source_camcorder">Camera</string>
     <string name="audio_source_default">Android default</string>
