Improve streaming camera controls

app/src/main/AndroidManifest.xml

@@ -4,6 +4,9 @@
 
     <!-- 摄像头权限 -->
     <uses-permission android:name="android.permission.CAMERA" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_CAMERA" />
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
 
     <!-- 网络权限：WebRTC / WebSocket / 信令服务器需要 -->
     <uses-permission android:name="android.permission.INTERNET" />
@@ -33,13 +36,19 @@
 
         <activity
             android:name=".MainActivity"
-            android:exported="true">
+            android:exported="true"
+            android:screenOrientation="landscape">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
 
+        <service
+            android:name=".PosefitStreamingService"
+            android:exported="false"
+            android:foregroundServiceType="camera" />
+
     </application>
 
 </manifest>

app/src/main/kotlin/com/kimgo/posefit/MainActivity.kt

@@ -2,7 +2,11 @@ package com.kimgo.posefit
 
 import android.Manifest
 import android.content.Context
+import android.content.Intent
+import android.content.pm.ActivityInfo
+import android.os.Build
 import android.os.Bundle
+import android.view.WindowManager
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.result.contract.ActivityResultContracts
@@ -11,21 +15,22 @@ import androidx.compose.material3.*
 import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import com.kimgo.posefit.sender.CameraCatalog
 import com.kimgo.posefit.sender.CameraFacing
-import com.kimgo.posefit.sender.WebRtcSenderClient
 import timber.log.Timber
 
 class MainActivity : ComponentActivity() {
 
-    private var webRtcClient: WebRtcSenderClient? = null
-
     private val requestPermission =
-        registerForActivityResult(ActivityResultContracts.RequestPermission()) { granted ->
+        registerForActivityResult(ActivityResultContracts.RequestMultiplePermissions()) { grants ->
-            if (granted) {
+            val cameraGranted = grants[Manifest.permission.CAMERA] == true
+            if (cameraGranted) {
                 val url = getSavedSignalingUrl()
                 val cameraFacing = getSavedCameraFacing()
-                startWebRtc(url, cameraFacing)
+                val cameraName = getSavedCameraName()
+                startWebRtc(url, cameraFacing, cameraName)
             } else {
                 Timber.w("Camera permission denied")
             }
@@ -34,6 +39,8 @@ class MainActivity : ComponentActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         Timber.d("MainActivity onCreate")
+        requestedOrientation = ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE
+        window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
 
         setContent {
             MaterialTheme {
@@ -51,70 +58,148 @@ class MainActivity : ComponentActivity() {
     fun ConfigScreen() {
         var url by remember { mutableStateOf(getSavedSignalingUrl()) }
         var cameraFacing by remember { mutableStateOf(getSavedCameraFacing()) }
-        var isStreaming by remember { mutableStateOf(false) }
+        var selectedCameraName by remember { mutableStateOf(getSavedCameraName()) }
+        var cameraMenuExpanded by remember { mutableStateOf(false) }
+        val cameraOptions = remember { CameraCatalog.listOptions(this) }
+        val selectedCameraLabel = remember(selectedCameraName, cameraOptions) {
+            cameraOptions.firstOrNull { it.name == selectedCameraName }?.label ?: "自动选择后置最广角"
+        }
+        var isStreaming by remember { mutableStateOf(PosefitStreamingService.isRunning) }
 
-        Column(
+        Row(
             modifier = Modifier
                 .fillMaxSize()
-                .padding(24.dp),
+                .padding(horizontal = 32.dp, vertical = 20.dp),
-            verticalArrangement = Arrangement.Center,
+            horizontalArrangement = Arrangement.spacedBy(28.dp),
-            horizontalAlignment = Alignment.CenterHorizontally
+            verticalAlignment = Alignment.CenterVertically
         ) {
-            Text(
+            Column(
-                text = "PoseFit 配置",
+                modifier = Modifier
-                style = MaterialTheme.typography.headlineMedium,
+                    .weight(0.9f)
-                color = MaterialTheme.colorScheme.primary
+                    .fillMaxHeight(),
-            )
+                verticalArrangement = Arrangement.Center,
-            Spacer(modifier = Modifier.height(32.dp))
+                horizontalAlignment = Alignment.Start
-            TextField(
-                value = url,
-                onValueChange = { url = it },
-                label = { Text("服务器地址 (ws://...)") },
-                modifier = Modifier.fillMaxWidth(),
-                enabled = !isStreaming
-            )
-            Spacer(modifier = Modifier.height(16.dp))
-            Text(
-                text = "选择摄像头",
-                style = MaterialTheme.typography.titleMedium,
-                modifier = Modifier.fillMaxWidth()
-            )
-            Spacer(modifier = Modifier.height(8.dp))
-            Row(
-                modifier = Modifier.fillMaxWidth(),
-                horizontalArrangement = Arrangement.spacedBy(12.dp)
             ) {
-                CameraFacingButton(
+                Text(
-                    text = "前置摄像头",
+                    text = "PoseFit",
-                    selected = cameraFacing == CameraFacing.FRONT,
+                    style = MaterialTheme.typography.headlineLarge,
-                    enabled = !isStreaming,
+                    fontWeight = FontWeight.Bold,
-                    modifier = Modifier.weight(1f),
+                    color = MaterialTheme.colorScheme.primary
-                    onClick = { cameraFacing = CameraFacing.FRONT }
                 )
-                CameraFacingButton(
+                Spacer(modifier = Modifier.height(8.dp))
-                    text = "后置摄像头",
+                Text(
-                    selected = cameraFacing == CameraFacing.BACK,
+                    text = if (isStreaming) "正在横屏 1080x720 推流" else "横屏 1080x720 推流未开始",
-                    enabled = !isStreaming,
+                    style = MaterialTheme.typography.titleMedium,
-                    modifier = Modifier.weight(1f),
+                    color = if (isStreaming) {
-                    onClick = { cameraFacing = CameraFacing.BACK }
+                        MaterialTheme.colorScheme.primary
-                )
-            }
-            Spacer(modifier = Modifier.height(16.dp))
-            Button(
-                onClick = {
-                    if (isStreaming) {
-                        stopWebRtc()
-                        isStreaming = false
                     } else {
-                        saveSignalingUrl(url)
+                        MaterialTheme.colorScheme.onSurfaceVariant
-                        saveCameraFacing(cameraFacing)
-                        requestPermission.launch(Manifest.permission.CAMERA)
-                        isStreaming = true
                     }
-                },
+                )
-                modifier = Modifier.fillMaxWidth()
+                Spacer(modifier = Modifier.height(24.dp))
+                Button(
+                    onClick = {
+                        if (isStreaming) {
+                            stopWebRtc()
+                            isStreaming = false
+                        } else {
+                            saveSignalingUrl(url)
+                            saveCameraFacing(cameraFacing)
+                            saveCameraName(selectedCameraName)
+                            requestPermission.launch(requiredPermissions())
+                            isStreaming = true
+                        }
+                    },
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .height(56.dp)
+                ) {
+                    Text(if (isStreaming) "停止推流" else "开始推流")
+                }
+            }
+
+            Column(
+                modifier = Modifier
+                    .weight(1.4f)
+                    .fillMaxHeight(),
+                verticalArrangement = Arrangement.Center,
+                horizontalAlignment = Alignment.Start
             ) {
-                Text(if (isStreaming) "停止推流" else "开始推流")
+                TextField(
+                    value = url,
+                    onValueChange = { url = it },
+                    label = { Text("服务器地址 (ws://...)") },
+                    modifier = Modifier.fillMaxWidth(),
+                    singleLine = true,
+                    enabled = !isStreaming
+                )
+                Spacer(modifier = Modifier.height(14.dp))
+                Text(text = "选择摄像头", style = MaterialTheme.typography.titleSmall)
+                Spacer(modifier = Modifier.height(8.dp))
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    horizontalArrangement = Arrangement.spacedBy(12.dp)
+                ) {
+                    CameraFacingButton(
+                        text = "前置",
+                        selected = cameraFacing == CameraFacing.FRONT && selectedCameraName == null,
+                        enabled = !isStreaming,
+                        modifier = Modifier
+                            .weight(1f)
+                            .height(48.dp),
+                        onClick = {
+                            cameraFacing = CameraFacing.FRONT
+                            selectedCameraName = null
+                        }
+                    )
+                    CameraFacingButton(
+                        text = "后置最广",
+                        selected = cameraFacing == CameraFacing.BACK && selectedCameraName == null,
+                        enabled = !isStreaming,
+                        modifier = Modifier
+                            .weight(1f)
+                            .height(48.dp),
+                        onClick = {
+                            cameraFacing = CameraFacing.BACK
+                            selectedCameraName = null
+                        }
+                    )
+                }
+                Spacer(modifier = Modifier.height(10.dp))
+                Box(modifier = Modifier.fillMaxWidth()) {
+                    OutlinedButton(
+                        onClick = { cameraMenuExpanded = true },
+                        enabled = !isStreaming,
+                        modifier = Modifier
+                            .fillMaxWidth()
+                            .height(48.dp)
+                    ) {
+                        Text(selectedCameraLabel, maxLines = 1)
+                    }
+                    DropdownMenu(
+                        expanded = cameraMenuExpanded,
+                        onDismissRequest = { cameraMenuExpanded = false },
+                    ) {
+                        DropdownMenuItem(
+                            text = { Text("自动选择后置最广角") },
+                            onClick = {
+                                cameraFacing = CameraFacing.BACK
+                                selectedCameraName = null
+                                cameraMenuExpanded = false
+                            }
+                        )
+                        cameraOptions.forEach { option ->
+                            DropdownMenuItem(
+                                text = { Text(option.label) },
+                                onClick = {
+                                    cameraFacing = option.facing
+                                    selectedCameraName = option.name
+                                    cameraMenuExpanded = false
+                                }
+                            )
+                        }
+                    }
+                }
             }
         }
     }
@@ -155,7 +240,7 @@ class MainActivity : ComponentActivity() {
 
     private fun getSavedSignalingUrl(): String {
         val prefs = getSharedPreferences("posefit_prefs", Context.MODE_PRIVATE)
-        return prefs.getString("signaling_url", "ws://192.168.2.10:8765") ?: "ws://192.168.2.10:8765"
+        return prefs.getString("signaling_url", "ws://192.168.2.6:8765") ?: "ws://192.168.2.6:8765"
     }
 
     private fun saveSignalingUrl(url: String) {
@@ -165,9 +250,9 @@ class MainActivity : ComponentActivity() {
 
     private fun getSavedCameraFacing(): CameraFacing {
         val prefs = getSharedPreferences("posefit_prefs", Context.MODE_PRIVATE)
-        val value = prefs.getString("camera_facing", CameraFacing.FRONT.name)
+        val value = prefs.getString("camera_facing", CameraFacing.BACK.name)
-        return runCatching { CameraFacing.valueOf(value ?: CameraFacing.FRONT.name) }
+        return runCatching { CameraFacing.valueOf(value ?: CameraFacing.BACK.name) }
-            .getOrDefault(CameraFacing.FRONT)
+            .getOrDefault(CameraFacing.BACK)
     }
 
     private fun saveCameraFacing(cameraFacing: CameraFacing) {
@@ -175,26 +260,42 @@ class MainActivity : ComponentActivity() {
         prefs.edit().putString("camera_facing", cameraFacing.name).apply()
     }
 
-    private fun startWebRtc(url: String, cameraFacing: CameraFacing) {
+    private fun getSavedCameraName(): String? {
-        Timber.i("startWebRtc: %s, cameraFacing=%s", url, cameraFacing)
+        val prefs = getSharedPreferences("posefit_prefs", Context.MODE_PRIVATE)
-        webRtcClient?.release()
+        return prefs.getString("camera_name", null)?.takeIf { it.isNotBlank() }
-        webRtcClient = WebRtcSenderClient(
+    }
-            context = this,
+
-            signalingUrl = url,
+    private fun saveCameraName(cameraName: String?) {
-            cameraFacing = cameraFacing
+        val prefs = getSharedPreferences("posefit_prefs", Context.MODE_PRIVATE)
-        )
+        prefs.edit().putString("camera_name", cameraName).apply()
-        webRtcClient?.start()
+    }
+
+    private fun startWebRtc(url: String, cameraFacing: CameraFacing, cameraName: String?) {
+        Timber.i("startWebRtc: %s, cameraFacing=%s, cameraName=%s", url, cameraFacing, cameraName)
+        val intent = PosefitStreamingService.startIntent(this, url, cameraFacing, cameraName)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            startForegroundService(intent)
+        } else {
+            startService(intent)
+        }
     }
 
     private fun stopWebRtc() {
         Timber.i("stopWebRtc")
-        webRtcClient?.release()
+        startService(PosefitStreamingService.stopIntent(this))
-        webRtcClient = null
+    }
+
+    private fun requiredPermissions(): Array<String> {
+        return buildList {
+            add(Manifest.permission.CAMERA)
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+                add(Manifest.permission.POST_NOTIFICATIONS)
+            }
+        }.toTypedArray()
     }
 
     override fun onDestroy() {
         super.onDestroy()
-        stopWebRtc()
         Timber.d("MainActivity onDestroy")
     }
 }

app/src/main/kotlin/com/kimgo/posefit/PosefitStreamingService.kt

@@ -0,0 +1,183 @@
+package com.kimgo.posefit
+
+import android.app.Notification
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.Service
+import android.content.Context
+import android.content.Intent
+import android.content.pm.ServiceInfo
+import android.os.Build
+import android.os.IBinder
+import com.kimgo.posefit.sender.CameraFacing
+import com.kimgo.posefit.sender.WebRtcSenderClient
+import timber.log.Timber
+
+class PosefitStreamingService : Service() {
+
+    private var webRtcClient: WebRtcSenderClient? = null
+
+    override fun onCreate() {
+        super.onCreate()
+        createNotificationChannel()
+    }
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        when (intent?.action) {
+            ACTION_STOP -> {
+                stopStreaming()
+                stopSelf()
+                return START_NOT_STICKY
+            }
+            ACTION_START -> {
+                val signalingUrl = intent.getStringExtra(EXTRA_SIGNALING_URL) ?: DEFAULT_SIGNALING_URL
+                val cameraFacing = intent.getStringExtra(EXTRA_CAMERA_FACING)
+                    ?.let { runCatching { CameraFacing.valueOf(it) }.getOrNull() }
+                    ?: CameraFacing.BACK
+                val preferredCameraName = intent.getStringExtra(EXTRA_CAMERA_NAME)
+
+                startForegroundNotification(signalingUrl, cameraFacing, preferredCameraName)
+                startStreaming(signalingUrl, cameraFacing, preferredCameraName)
+                return START_STICKY
+            }
+            else -> {
+                val signalingUrl = getSavedSignalingUrl()
+                val cameraFacing = getSavedCameraFacing()
+                val preferredCameraName = getSavedCameraName()
+                startForegroundNotification(signalingUrl, cameraFacing, preferredCameraName)
+                startStreaming(signalingUrl, cameraFacing, preferredCameraName)
+                return START_STICKY
+            }
+        }
+    }
+
+    override fun onBind(intent: Intent?): IBinder? = null
+
+    override fun onDestroy() {
+        stopStreaming()
+        super.onDestroy()
+    }
+
+    private fun startStreaming(signalingUrl: String, cameraFacing: CameraFacing, preferredCameraName: String?) {
+        Timber.i(
+            "Streaming service start: %s, cameraFacing=%s, preferredCameraName=%s, orientation=landscape",
+            signalingUrl,
+            cameraFacing,
+            preferredCameraName,
+        )
+        webRtcClient?.release()
+        webRtcClient = WebRtcSenderClient(
+            context = applicationContext,
+            signalingUrl = signalingUrl,
+            cameraFacing = cameraFacing,
+            preferredCameraName = preferredCameraName,
+        ).also { it.start() }
+        isRunning = true
+    }
+
+    private fun stopStreaming() {
+        Timber.i("Streaming service stop")
+        webRtcClient?.release()
+        webRtcClient = null
+        isRunning = false
+    }
+
+    private fun startForegroundNotification(signalingUrl: String, cameraFacing: CameraFacing, preferredCameraName: String?) {
+        val notification = buildNotification(signalingUrl, cameraFacing, preferredCameraName)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+            startForeground(NOTIFICATION_ID, notification, ServiceInfo.FOREGROUND_SERVICE_TYPE_CAMERA)
+        } else {
+            startForeground(NOTIFICATION_ID, notification)
+        }
+    }
+
+    private fun buildNotification(signalingUrl: String, cameraFacing: CameraFacing, preferredCameraName: String?): Notification {
+        val cameraText = when (cameraFacing) {
+            CameraFacing.FRONT -> "前置摄像头"
+            CameraFacing.BACK -> "后置摄像头"
+        }
+        val cameraModeText = preferredCameraName?.let { "$cameraText $it" } ?: "$cameraText 自动最广角"
+
+        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            Notification.Builder(this, CHANNEL_ID)
+                .setContentTitle("PoseFit 正在推流")
+                .setContentText("$cameraModeText 横屏720p -> $signalingUrl")
+                .setSmallIcon(R.mipmap.ic_launcher)
+                .setOngoing(true)
+                .build()
+        } else {
+            Notification.Builder(this)
+                .setContentTitle("PoseFit 正在推流")
+                .setContentText("$cameraModeText 横屏720p -> $signalingUrl")
+                .setSmallIcon(R.mipmap.ic_launcher)
+                .setOngoing(true)
+                .build()
+        }
+    }
+
+    private fun createNotificationChannel() {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
+            return
+        }
+
+        val channel = NotificationChannel(
+            CHANNEL_ID,
+            "PoseFit 推流",
+            NotificationManager.IMPORTANCE_LOW
+        )
+        val manager = getSystemService(NotificationManager::class.java)
+        manager.createNotificationChannel(channel)
+    }
+
+    private fun getSavedSignalingUrl(): String {
+        val prefs = getSharedPreferences("posefit_prefs", Context.MODE_PRIVATE)
+        return prefs.getString("signaling_url", DEFAULT_SIGNALING_URL) ?: DEFAULT_SIGNALING_URL
+    }
+
+    private fun getSavedCameraFacing(): CameraFacing {
+        val prefs = getSharedPreferences("posefit_prefs", Context.MODE_PRIVATE)
+        val value = prefs.getString("camera_facing", CameraFacing.BACK.name)
+        return runCatching { CameraFacing.valueOf(value ?: CameraFacing.BACK.name) }
+            .getOrDefault(CameraFacing.BACK)
+    }
+
+    private fun getSavedCameraName(): String? {
+        val prefs = getSharedPreferences("posefit_prefs", Context.MODE_PRIVATE)
+        return prefs.getString("camera_name", null)?.takeIf { it.isNotBlank() }
+    }
+
+    companion object {
+        private const val CHANNEL_ID = "posefit_streaming"
+        private const val NOTIFICATION_ID = 1001
+        private const val ACTION_START = "com.kimgo.posefit.action.START_STREAMING"
+        private const val ACTION_STOP = "com.kimgo.posefit.action.STOP_STREAMING"
+        private const val EXTRA_SIGNALING_URL = "extra_signaling_url"
+        private const val EXTRA_CAMERA_FACING = "extra_camera_facing"
+        private const val EXTRA_CAMERA_NAME = "extra_camera_name"
+        private const val DEFAULT_SIGNALING_URL = "ws://192.168.2.6:8765"
+
+        @Volatile
+        var isRunning: Boolean = false
+            private set
+
+        fun startIntent(
+            context: Context,
+            signalingUrl: String,
+            cameraFacing: CameraFacing,
+            preferredCameraName: String?
+        ): Intent {
+            return Intent(context, PosefitStreamingService::class.java).apply {
+                action = ACTION_START
+                putExtra(EXTRA_SIGNALING_URL, signalingUrl)
+                putExtra(EXTRA_CAMERA_FACING, cameraFacing.name)
+                putExtra(EXTRA_CAMERA_NAME, preferredCameraName)
+            }
+        }
+
+        fun stopIntent(context: Context): Intent {
+            return Intent(context, PosefitStreamingService::class.java).apply {
+                action = ACTION_STOP
+            }
+        }
+    }
+}

app/src/main/kotlin/com/kimgo/posefit/sender/CameraCatalog.kt

@@ -0,0 +1,44 @@
+package com.kimgo.posefit.sender
+
+import android.content.Context
+import android.hardware.camera2.CameraCharacteristics
+import android.hardware.camera2.CameraManager
+import org.webrtc.Camera2Enumerator
+
+object CameraCatalog {
+    fun listOptions(context: Context): List<CameraOption> {
+        val enumerator = Camera2Enumerator(context)
+        val cameraManager = context.getSystemService(Context.CAMERA_SERVICE) as CameraManager
+
+        return enumerator.deviceNames.mapNotNull { cameraName ->
+            val facing = when {
+                enumerator.isFrontFacing(cameraName) -> CameraFacing.FRONT
+                enumerator.isBackFacing(cameraName) -> CameraFacing.BACK
+                else -> return@mapNotNull null
+            }
+            val focalLengths = runCatching {
+                cameraManager.getCameraCharacteristics(cameraName)
+                    .get(CameraCharacteristics.LENS_INFO_AVAILABLE_FOCAL_LENGTHS)
+                    ?.toList()
+                    .orEmpty()
+            }.getOrDefault(emptyList())
+
+            CameraOption(
+                name = cameraName,
+                facing = facing,
+                focalLengths = focalLengths
+            )
+        }.sortedWith(
+            compareBy<CameraOption> { it.facing != CameraFacing.BACK }
+                .thenBy { it.minFocalLength ?: Float.MAX_VALUE }
+                .thenBy { it.name }
+        )
+    }
+
+    fun widestBackCameraName(context: Context): String? {
+        return listOptions(context)
+            .filter { it.facing == CameraFacing.BACK }
+            .minByOrNull { it.minFocalLength ?: Float.MAX_VALUE }
+            ?.name
+    }
+}

app/src/main/kotlin/com/kimgo/posefit/sender/CameraOption.kt

@@ -0,0 +1,20 @@
+package com.kimgo.posefit.sender
+
+data class CameraOption(
+    val name: String,
+    val facing: CameraFacing,
+    val focalLengths: List<Float>
+) {
+    val minFocalLength: Float?
+        get() = focalLengths.minOrNull()
+
+    val label: String
+        get() {
+            val facingText = when (facing) {
+                CameraFacing.FRONT -> "前置"
+                CameraFacing.BACK -> "后置"
+            }
+            val focalText = minFocalLength?.let { "%.2fmm".format(it) } ?: "未知焦距"
+            return "$facingText $focalText ($name)"
+        }
+}

app/src/main/kotlin/com/kimgo/posefit/sender/WebRtcSenderClient.kt

@@ -9,9 +9,18 @@ import timber.log.Timber
 class WebRtcSenderClient(
     private val context: Context,
     private val signalingUrl: String,
-    private val cameraFacing: CameraFacing = CameraFacing.FRONT
+    private val cameraFacing: CameraFacing = CameraFacing.BACK,
+    private val preferredCameraName: String? = null
 ) {
 
+    private companion object {
+        const val VIDEO_WIDTH = 1080
+        const val VIDEO_HEIGHT = 720
+        const val VIDEO_FPS = 30
+        const val VIDEO_MIN_BITRATE_BPS = 3_000_000
+        const val VIDEO_MAX_BITRATE_BPS = 6_000_000
+    }
+
     private val eglBase = EglBase.create()
     private val okHttpClient = OkHttpClient()
 
@@ -22,10 +31,16 @@ class WebRtcSenderClient(
     private var videoCapturer: CameraVideoCapturer? = null
     private var videoSource: VideoSource? = null
     private var videoTrack: VideoTrack? = null
+    private var videoSender: RtpSender? = null
     private var surfaceTextureHelper: SurfaceTextureHelper? = null
 
     fun start() {
-        Timber.i("WebRTC starting, signalingUrl=%s, cameraFacing=%s", signalingUrl, cameraFacing)
+        Timber.i(
+            "WebRTC starting, signalingUrl=%s, cameraFacing=%s, preferredCameraName=%s",
+            signalingUrl,
+            cameraFacing,
+            preferredCameraName
+        )
         initPeerConnectionFactory()
         connectSignaling()
     }
@@ -147,24 +162,57 @@ class WebRtcSenderClient(
             videoSource?.capturerObserver
         )
 
-        videoCapturer?.startCapture(1280, 720, 30)
+        videoCapturer?.startCapture(VIDEO_WIDTH, VIDEO_HEIGHT, VIDEO_FPS)
 
         videoTrack = factory.createVideoTrack("video_track", videoSource)
 
-        peerConnection?.addTrack(
+        videoSender = peerConnection?.addTrack(
             videoTrack,
             listOf("posefit_stream")
         )
+        videoSender?.let { configureVideoSender(it) }
 
-        Timber.d("Camera started: %s, resolution=1280x720@30fps", cameraName)
+        Timber.d("Camera started: %s, resolution=%dx%d@%dfps", cameraName, VIDEO_WIDTH, VIDEO_HEIGHT, VIDEO_FPS)
+    }
+
+    private fun configureVideoSender(sender: RtpSender) {
+        val parameters = sender.parameters ?: run {
+            Timber.w("Video sender parameters unavailable")
+            return
+        }
+
+        parameters.degradationPreference = RtpParameters.DegradationPreference.MAINTAIN_RESOLUTION
+        parameters.encodings.forEach { encoding ->
+            encoding.active = true
+            encoding.scaleResolutionDownBy = 1.0
+            encoding.maxFramerate = VIDEO_FPS
+            encoding.minBitrateBps = VIDEO_MIN_BITRATE_BPS
+            encoding.maxBitrateBps = VIDEO_MAX_BITRATE_BPS
+        }
+
+        val applied = sender.setParameters(parameters)
+        Timber.d(
+            "Video sender configured: applied=%s, resolution=%dx%d@%dfps, bitrate=%d-%d",
+            applied,
+            VIDEO_WIDTH,
+            VIDEO_HEIGHT,
+            VIDEO_FPS,
+            VIDEO_MIN_BITRATE_BPS,
+            VIDEO_MAX_BITRATE_BPS,
+        )
     }
 
     private fun selectCamera(enumerator: Camera2Enumerator): String {
-        val preferredCamera = enumerator.deviceNames.firstOrNull { cameraName ->
+        logAvailableCameras(enumerator)
-            when (cameraFacing) {
+
-                CameraFacing.FRONT -> enumerator.isFrontFacing(cameraName)
+        if (!preferredCameraName.isNullOrBlank() && preferredCameraName in enumerator.deviceNames) {
-                CameraFacing.BACK -> enumerator.isBackFacing(cameraName)
+            Timber.i("Selected explicit camera: %s", preferredCameraName)
-            }
+            return preferredCameraName
+        }
+
+        val preferredCamera = when (cameraFacing) {
+            CameraFacing.FRONT -> enumerator.deviceNames.firstOrNull { enumerator.isFrontFacing(it) }
+            CameraFacing.BACK -> selectWidestBackCamera(enumerator)
         }
 
         if (preferredCamera != null) {
@@ -175,6 +223,31 @@ class WebRtcSenderClient(
         return enumerator.deviceNames.first()
     }
 
+    private fun selectWidestBackCamera(enumerator: Camera2Enumerator): String? {
+        val backCameras = enumerator.deviceNames.filter { enumerator.isBackFacing(it) }
+        if (backCameras.isEmpty()) {
+            return null
+        }
+
+        val widestCamera = CameraCatalog.widestBackCameraName(context)
+
+        Timber.i("Selected widest back camera: %s", widestCamera)
+        return widestCamera ?: backCameras.first()
+    }
+
+    private fun logAvailableCameras(enumerator: Camera2Enumerator) {
+        val knownOptions = CameraCatalog.listOptions(context).associateBy { it.name }
+        enumerator.deviceNames.forEach { cameraName ->
+            val option = knownOptions[cameraName]
+            Timber.i(
+                "Camera available: name=%s, facing=%s, focalLengths=%s",
+                cameraName,
+                option?.facing ?: "unknown",
+                option?.focalLengths,
+            )
+        }
+    }
+
     private fun createOffer() {
         val constraints = MediaConstraints().apply {
             mandatory.add(
@@ -188,11 +261,16 @@ class WebRtcSenderClient(
         peerConnection?.createOffer(object : SdpObserver {
 
             override fun onCreateSuccess(desc: SessionDescription) {
+                val fixedVideoDesc = SessionDescription(
+                    desc.type,
+                    forceVideoBandwidth(desc.description)
+                )
+
                 peerConnection?.setLocalDescription(object : SdpObserver {
                     override fun onSetSuccess() {
                         val json = JSONObject().apply {
-                            put("type", desc.type.canonicalForm())
+                            put("type", fixedVideoDesc.type.canonicalForm())
-                            put("sdp", desc.description)
+                            put("sdp", fixedVideoDesc.description)
                         }
 
                         webSocket.send(json.toString())
@@ -207,7 +285,7 @@ class WebRtcSenderClient(
                     override fun onCreateFailure(error: String) {
                         Timber.e("createOffer failed: %s", error)
                     }
-                }, desc)
+                }, fixedVideoDesc)
             }
 
             override fun onSetSuccess() {}
@@ -221,6 +299,35 @@ class WebRtcSenderClient(
         }, constraints)
     }
 
+    private fun forceVideoBandwidth(sdp: String): String {
+        val lines = sdp.split("\r\n").toMutableList()
+        val videoStart = lines.indexOfFirst { it.startsWith("m=video") }
+        if (videoStart == -1) {
+            return sdp
+        }
+
+        val videoEnd = lines.drop(videoStart + 1)
+            .indexOfFirst { it.startsWith("m=") }
+            .let { if (it == -1) lines.size else videoStart + 1 + it }
+
+        val bandwidthLine = "b=AS:${VIDEO_MAX_BITRATE_BPS / 1000}"
+        val existingBandwidth = (videoStart until videoEnd).firstOrNull { index ->
+            lines[index].startsWith("b=AS:") || lines[index].startsWith("b=TIAS:")
+        }
+
+        if (existingBandwidth != null) {
+            lines[existingBandwidth] = bandwidthLine
+        } else {
+            val insertAt = (videoStart + 1 until videoEnd).firstOrNull { index ->
+                lines[index].startsWith("a=")
+            } ?: videoEnd
+            lines.add(insertAt, bandwidthLine)
+        }
+
+        Timber.d("Forced video SDP bandwidth: %s", bandwidthLine)
+        return lines.joinToString("\r\n")
+    }
+
     private fun handleSignalingMessage(text: String) {
         val json = JSONObject(text)
 
@@ -261,12 +368,17 @@ class WebRtcSenderClient(
         videoCapturer?.dispose()
         videoSource?.dispose()
         videoTrack?.dispose()
+        videoSender = null
         surfaceTextureHelper?.dispose()
         peerConnection?.close()
         peerConnection?.dispose()
-        factory.dispose()
+        if (::factory.isInitialized) {
+            factory.dispose()
+        }
         eglBase.release()
-        webSocket.close(1000, "close")
+        if (::webSocket.isInitialized) {
+            webSocket.close(1000, "close")
+        }
         okHttpClient.dispatcher.executorService.shutdown()
 
         Timber.d("WebRTC released")