diff --git a/Front/android/app/src/main/AndroidManifest.xml b/Front/android/app/src/main/AndroidManifest.xml
index 2ab0a0a..969b7f2 100644
--- a/Front/android/app/src/main/AndroidManifest.xml
+++ b/Front/android/app/src/main/AndroidManifest.xml
@@ -22,6 +22,11 @@
android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
android:hardwareAccelerated="true"
android:windowSoftInputMode="adjustResize">
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diff --git a/call/android/app/src/main/AndroidManifest.xml b/call/android/app/src/main/AndroidManifest.xml
new file mode 100644
index 0000000..60bf473
--- /dev/null
+++ b/call/android/app/src/main/AndroidManifest.xml
@@ -0,0 +1,50 @@
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diff --git a/call/android/app/src/main/kotlin/com/example/call/AudioEngine.kt b/call/android/app/src/main/kotlin/com/example/call/AudioEngine.kt
new file mode 100644
index 0000000..3cee2be
--- /dev/null
+++ b/call/android/app/src/main/kotlin/com/example/call/AudioEngine.kt
@@ -0,0 +1,288 @@
+package com.example.call
+
+import android.content.Context
+import android.media.*
+import android.os.Handler
+import android.os.Looper
+import android.util.Log
+import io.flutter.plugin.common.BinaryMessenger
+import io.flutter.plugin.common.EventChannel
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+import java.nio.ByteBuffer
+import java.util.concurrent.atomic.AtomicBoolean
+
+/**
+ * AudioEngine — Android native layer for low-latency audio I/O.
+ *
+ * MethodChannel "com.example.call/audio_control"
+ * startCapture(sampleRate: Int, source: Int) → "ok"
+ * stopCapture() → "ok"
+ * startPlayback(sampleRate: Int) → "ok"
+ * stopPlayback() → "ok"
+ * writePlayback(samples: ByteArray) → "ok" (Int16 LE samples)
+ * setSpeakerMode(enabled: Boolean) → "ok"
+ * getAudioRouteInfo() → Map
+ *
+ * EventChannel "com.example.call/audio_capture"
+ * Streams ByteArray (Int16 LE) chunks captured from AudioRecord.
+ * Each event is exactly CAPTURE_CHUNK_SAMPLES × 2 bytes.
+ */
+object AudioEngine {
+
+ private const val TAG = "AudioEngine"
+
+ // ── Channel names ────────────────────────────────────────────────
+ const val METHOD_CHANNEL = "com.example.call/audio_control"
+ const val EVENT_CHANNEL = "com.example.call/audio_capture"
+
+ // ── Audio parameters ─────────────────────────────────────────────
+ // Matches the modem sample rate; must be 8000 Hz for cellular compatibility.
+ private const val SAMPLE_RATE = 8000
+
+ // Number of Int16 samples delivered per EventChannel event.
+ // 160 samples = 20 ms at 8 kHz → one LPC subframe.
+ private const val CAPTURE_CHUNK_SAMPLES = 160
+
+ // Internal AudioRecord buffer: 4× chunk size to reduce overruns.
+ private const val RECORD_BUFFER_SAMPLES = CAPTURE_CHUNK_SAMPLES * 4
+
+ // Internal AudioTrack buffer: 80 ms headroom.
+ private const val PLAYBACK_BUFFER_SAMPLES = SAMPLE_RATE / 1000 * 80
+
+ // ── State ────────────────────────────────────────────────────────
+ private var audioRecord: AudioRecord? = null
+ private var audioTrack: AudioTrack? = null
+ private var captureThread: Thread? = null
+ private val capturing = AtomicBoolean(false)
+ private val playing = AtomicBoolean(false)
+
+ private var eventSink: EventChannel.EventSink? = null
+ private val mainHandler = Handler(Looper.getMainLooper())
+
+ private lateinit var appContext: Context
+
+ // ── Registration ─────────────────────────────────────────────────
+ fun register(context: Context, messenger: BinaryMessenger) {
+ appContext = context.applicationContext
+
+ MethodChannel(messenger, METHOD_CHANNEL).setMethodCallHandler { call, result ->
+ handleMethod(call, result)
+ }
+ EventChannel(messenger, EVENT_CHANNEL).setStreamHandler(object : EventChannel.StreamHandler {
+ override fun onListen(args: Any?, sink: EventChannel.EventSink?) {
+ eventSink = sink
+ }
+ override fun onCancel(args: Any?) {
+ eventSink = null
+ }
+ })
+ }
+
+ // ── Method handler ───────────────────────────────────────────────
+ private fun handleMethod(call: MethodCall, result: MethodChannel.Result) {
+ when (call.method) {
+ "startCapture" -> {
+ val rate = call.argument("sampleRate") ?: SAMPLE_RATE
+ val source = call.argument("source") ?: MediaRecorder.AudioSource.UNPROCESSED
+ startCapture(rate, source)
+ result.success("ok")
+ }
+ "stopCapture" -> {
+ stopCapture()
+ result.success("ok")
+ }
+ "startPlayback" -> {
+ val rate = call.argument("sampleRate") ?: SAMPLE_RATE
+ startPlayback(rate)
+ result.success("ok")
+ }
+ "stopPlayback" -> {
+ stopPlayback()
+ result.success("ok")
+ }
+ "writePlayback" -> {
+ val bytes = call.argument("samples")
+ if (bytes != null) writePlayback(bytes)
+ result.success("ok")
+ }
+ "setSpeakerMode" -> {
+ val enabled = call.argument("enabled") ?: true
+ setSpeakerMode(enabled)
+ result.success("ok")
+ }
+ "getAudioRouteInfo" -> {
+ result.success(getAudioRouteInfo())
+ }
+ else -> result.notImplemented()
+ }
+ }
+
+ // ── Capture ──────────────────────────────────────────────────────
+
+ /**
+ * Start capturing audio from the microphone.
+ *
+ * Source priority (best for FSK demodulation):
+ * 1. UNPROCESSED (API 24+) — raw mic, no AEC/NS
+ * 2. VOICE_COMMUNICATION — VoIP-tuned processing
+ * 3. MIC — standard mic
+ *
+ * @param sampleRate Hz
+ * @param preferredSource MediaRecorder.AudioSource constant
+ */
+ private fun startCapture(sampleRate: Int, preferredSource: Int) {
+ if (capturing.get()) {
+ Log.w(TAG, "startCapture called while already capturing")
+ return
+ }
+
+ val sources = listOf(
+ preferredSource,
+ MediaRecorder.AudioSource.UNPROCESSED,
+ MediaRecorder.AudioSource.VOICE_COMMUNICATION,
+ MediaRecorder.AudioSource.MIC
+ ).distinct()
+
+ val bufferBytes = RECORD_BUFFER_SAMPLES * 2 // Int16 → 2 bytes each
+ val format = AudioFormat.Builder()
+ .setSampleRate(sampleRate)
+ .setEncoding(AudioFormat.ENCODING_PCM_16BIT)
+ .setChannelMask(AudioFormat.CHANNEL_IN_MONO)
+ .build()
+
+ var record: AudioRecord? = null
+ for (src in sources) {
+ try {
+ val rec = AudioRecord.Builder()
+ .setAudioSource(src)
+ .setAudioFormat(format)
+ .setBufferSizeInBytes(bufferBytes)
+ .build()
+ if (rec.state == AudioRecord.STATE_INITIALIZED) {
+ record = rec
+ Log.i(TAG, "AudioRecord opened with source=$src")
+ break
+ } else {
+ rec.release()
+ }
+ } catch (e: Exception) {
+ Log.w(TAG, "Source $src failed: ${e.message}")
+ }
+ }
+
+ if (record == null) {
+ Log.e(TAG, "Could not open AudioRecord with any source")
+ return
+ }
+
+ audioRecord = record
+ capturing.set(true)
+
+ captureThread = Thread({
+ android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO)
+ val chunk = ShortArray(CAPTURE_CHUNK_SAMPLES)
+ record.startRecording()
+ while (capturing.get()) {
+ val read = record.read(chunk, 0, chunk.size)
+ if (read > 0) {
+ // Convert ShortArray → ByteArray (Int16 LE) for Dart
+ val bytes = ByteArray(read * 2)
+ val buf = ByteBuffer.wrap(bytes).order(java.nio.ByteOrder.LITTLE_ENDIAN)
+ for (i in 0 until read) buf.putShort(chunk[i])
+ // Dispatch to Dart via EventChannel on main thread
+ val payload = bytes.copyOf()
+ mainHandler.post { eventSink?.success(payload) }
+ }
+ }
+ record.stop()
+ record.release()
+ }, "AudioCapture")
+ captureThread!!.start()
+ }
+
+ private fun stopCapture() {
+ capturing.set(false)
+ captureThread?.join(500)
+ captureThread = null
+ audioRecord = null
+ }
+
+ // ── Playback ─────────────────────────────────────────────────────
+
+ /**
+ * Start the AudioTrack in streaming mode.
+ * Dart pushes PCM chunks via writePlayback().
+ */
+ private fun startPlayback(sampleRate: Int) {
+ if (playing.get()) return
+
+ val bufBytes = PLAYBACK_BUFFER_SAMPLES * 2
+ val track = AudioTrack.Builder()
+ .setAudioAttributes(
+ AudioAttributes.Builder()
+ .setUsage(AudioAttributes.USAGE_VOICE_COMMUNICATION)
+ .setContentType(AudioAttributes.CONTENT_TYPE_SPEECH)
+ .build()
+ )
+ .setAudioFormat(
+ AudioFormat.Builder()
+ .setSampleRate(sampleRate)
+ .setEncoding(AudioFormat.ENCODING_PCM_16BIT)
+ .setChannelMask(AudioFormat.CHANNEL_OUT_MONO)
+ .build()
+ )
+ .setBufferSizeInBytes(bufBytes)
+ .setTransferMode(AudioTrack.MODE_STREAM)
+ .build()
+
+ track.play()
+ audioTrack = track
+ playing.set(true)
+ Log.i(TAG, "AudioTrack started, sampleRate=$sampleRate")
+ }
+
+ /**
+ * Write Int16 LE PCM bytes to the AudioTrack buffer.
+ * Called from Dart whenever the FSK modulator or LPC decoder produces output.
+ */
+ private fun writePlayback(bytes: ByteArray) {
+ val track = audioTrack ?: return
+ if (!playing.get()) return
+ // Write non-blocking; discard if buffer full (transient)
+ track.write(bytes, 0, bytes.size, AudioTrack.WRITE_NON_BLOCKING)
+ }
+
+ private fun stopPlayback() {
+ playing.set(false)
+ audioTrack?.stop()
+ audioTrack?.release()
+ audioTrack = null
+ }
+
+ // ── Routing ──────────────────────────────────────────────────────
+
+ /**
+ * Switch between speakerphone (loudspeaker mode) and earpiece.
+ *
+ * FSK acoustic coupling requires SPEAKER mode so the phone's bottom mic
+ * can pick up audio coming from the speaker. When receiving decoded voice,
+ * you may optionally switch to earpiece for privacy.
+ */
+ private fun setSpeakerMode(enabled: Boolean) {
+ val am = appContext.getSystemService(Context.AUDIO_SERVICE) as AudioManager
+ am.mode = AudioManager.MODE_IN_COMMUNICATION
+ am.isSpeakerphoneOn = enabled
+ Log.i(TAG, "Speaker mode: $enabled")
+ }
+
+ private fun getAudioRouteInfo(): Map {
+ val am = appContext.getSystemService(Context.AUDIO_SERVICE) as AudioManager
+ return mapOf(
+ "speakerOn" to am.isSpeakerphoneOn,
+ "mode" to am.mode,
+ "sampleRate" to SAMPLE_RATE,
+ "chunkSize" to CAPTURE_CHUNK_SAMPLES
+ )
+ }
+}
diff --git a/call/android/app/src/main/kotlin/com/example/call/MainActivity.kt b/call/android/app/src/main/kotlin/com/example/call/MainActivity.kt
new file mode 100644
index 0000000..d37f110
--- /dev/null
+++ b/call/android/app/src/main/kotlin/com/example/call/MainActivity.kt
@@ -0,0 +1,12 @@
+package com.example.call
+
+import io.flutter.embedding.android.FlutterActivity
+import io.flutter.embedding.engine.FlutterEngine
+
+class MainActivity : FlutterActivity() {
+ override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
+ super.configureFlutterEngine(flutterEngine)
+ // Register the AudioEngine method channel and event channel.
+ AudioEngine.register(this, flutterEngine.dartExecutor.binaryMessenger)
+ }
+}
diff --git a/call/android/app/src/main/res/drawable-v21/launch_background.xml b/call/android/app/src/main/res/drawable-v21/launch_background.xml
new file mode 100644
index 0000000..f74085f
--- /dev/null
+++ b/call/android/app/src/main/res/drawable-v21/launch_background.xml
@@ -0,0 +1,12 @@
+
+
+
+