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libraries/textcomposer/impl/src/main/kotlin/io/element/android/libraries/textcomposer/model/VoiceMessageState.kt

@@ -21,11 +21,13 @@ sealed interface VoiceMessageState {
         val showCursor: Boolean,
         val playbackProgress: Float,
         val time: Duration,
+        // Values are between 0 and 1
         val waveform: ImmutableList<Float>,
     ) : VoiceMessageState
 
     data class Recording(
         val duration: Duration,
+        // Values are between 0 and 1
         val levels: ImmutableList<Float>,
     ) : VoiceMessageState
 }

libraries/voicerecorder/api/src/main/kotlin/io/element/android/libraries/voicerecorder/api/VoiceRecorderState.kt

@@ -22,16 +22,19 @@ sealed interface VoiceRecorderState {
      * The recorder is currently recording.
      *
      * @property elapsedTime The elapsed time since the recording started.
-     * @property levels The current audio levels of the recording as a fraction of 1.
+     * @property levels The current audio levels of the recording as a fraction of 1. All values are between 0 and 1.
      */
-    data class Recording(val elapsedTime: Duration, val levels: List<Float>) : VoiceRecorderState
+    data class Recording(
+        val elapsedTime: Duration,
+        val levels: List<Float>,
+    ) : VoiceRecorderState
 
     /**
      * The recorder has finished recording.
      *
      * @property file The recorded file.
      * @property mimeType The mime type of the file.
-     * @property waveform The waveform of the recording.
+     * @property waveform The waveform of the recording. All values are between 0 and 1.
      * @property duration The total time spent recording.
      */
     data class Finished(

libraries/voicerecorder/impl/src/main/kotlin/io/element/android/libraries/voicerecorder/impl/DefaultVoiceRecorder.kt

@@ -63,6 +63,8 @@ class DefaultVoiceRecorder(
     private var outputFile: File? = null
     private var audioReader: AudioReader? = null
     private var recordingJob: Job? = null
+
+    // List of Float between 0 and 1 representing the audio levels
     private val levels: MutableList<Float> = mutableListOf()
     private val lock = Mutex()
 

libraries/voicerecorder/impl/src/main/kotlin/io/element/android/libraries/voicerecorder/impl/audio/AudioLevelCalculator.kt

@@ -7,6 +7,8 @@
 
 package io.element.android.libraries.voicerecorder.impl.audio
 
+import androidx.annotation.FloatRange
+
 interface AudioLevelCalculator {
     /**
      * Calculate the audio level of the audio buffer.
@@ -14,5 +16,6 @@ interface AudioLevelCalculator {
      * @param buffer The audio buffer containing 16bit PCM audio data.
      * @return A float value between 0 and 1 proportional to the audio level.
      */
+    @FloatRange(from = 0.0, to = 1.0)
     fun calculateAudioLevel(buffer: ShortArray): Float
 }