desktop: support sending voice messages, use shared VLC media-player factory (#6739)

* desktop: support sending voice messages

* alert for unsupported platforms

* dont record on error

* better initialization

* desktop: use shared VLC media-player factory (#6741)

* desktop: use shared VLC media-player factory

* fix factory

---------

Co-authored-by: Evgeny @ SimpleX Chat <259188159+evgeny-simplex@users.noreply.github.com>

---------

Co-authored-by: Evgeny @ SimpleX Chat <259188159+evgeny-simplex@users.noreply.github.com>

apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/views/chat/SendMsgView.kt

@@ -24,7 +24,6 @@ import chat.simplex.common.views.chat.item.ItemAction
 import chat.simplex.common.views.helpers.*
 import chat.simplex.common.model.ChatItem
 import chat.simplex.common.platform.*
-import chat.simplex.common.views.usersettings.showInDevelopingAlert
 import chat.simplex.res.MR
 import dev.icerock.moko.resources.compose.stringResource
 import dev.icerock.moko.resources.compose.painterResource
@@ -313,21 +312,19 @@ private fun RecordVoiceView(recState: MutableState<RecordingState>, stopRecOnNex
     LockToCurrentOrientationUntilDispose()
     StopRecordButton(stopRecordingAndAddAudio)
   } else {
-    val startRecording: () -> Unit = out@ {
-      if (appPlatform.isDesktop) {
-        return@out showInDevelopingAlert()
+    val startRecording: () -> Unit = {
+      val filePath = rec.start { progress: Int?, finished: Boolean ->
+        val state = recState.value
+        if (state is RecordingState.Started && progress != null) {
+          recState.value = if (!finished)
+            RecordingState.Started(state.filePath, progress)
+          else
+            RecordingState.Finished(state.filePath, progress)
+        }
+      }
+      if (filePath.isNotEmpty()) {
+        recState.value = RecordingState.Started(filePath = filePath)
       }
-      recState.value = RecordingState.Started(
-        filePath = rec.start { progress: Int?, finished: Boolean ->
-          val state = recState.value
-          if (state is RecordingState.Started && progress != null) {
-            recState.value = if (!finished)
-              RecordingState.Started(state.filePath, progress)
-            else
-              RecordingState.Finished(state.filePath, progress)
-          }
-        },
-      )
     }
     val interactionSource = interactionSourceWithTapDetection(
       onPress = { if (recState.value is RecordingState.NotStarted) startRecording() },

apps/multiplatform/common/src/commonMain/resources/MR/base/strings.xml

@@ -54,6 +54,7 @@
   <string name="blocked_by_admin_items_description">%d messages blocked by admin</string>
   <string name="sending_files_not_yet_supported">sending files is not supported yet</string>
   <string name="receiving_files_not_yet_supported">receiving files is not supported yet</string>
+  <string name="voice_recording_not_supported">Voice recording is not supported on your platform</string>
   <string name="sender_you_pronoun">you</string>
   <string name="unknown_message_format">unknown message format</string>
   <string name="invalid_message_format">invalid message format</string>

apps/multiplatform/common/src/desktopMain/kotlin/chat/simplex/common/platform/RecAndPlay.desktop.kt

@@ -5,6 +5,7 @@ import chat.simplex.common.model.*
 import chat.simplex.common.views.helpers.*
 import chat.simplex.res.MR
 import kotlinx.coroutines.*
+import uk.co.caprica.vlcj.factory.MediaPlayerFactory
 import uk.co.caprica.vlcj.player.base.MediaPlayer
 import uk.co.caprica.vlcj.player.base.State
 import uk.co.caprica.vlcj.player.component.AudioPlayerComponent
@@ -12,20 +13,77 @@ import java.io.File
 import java.util.*
 import kotlin.math.max
 
+internal val vlcFactory: MediaPlayerFactory by lazy { MediaPlayerFactory() }
+
 actual class RecorderNative: RecorderInterface {
+  private var player: MediaPlayer? = null
+  private var progressJob: Job? = null
+  private var filePath: String? = null
+  private var recStartedAt: Long? = null
+
   override fun start(onProgressUpdate: (position: Int?, finished: Boolean) -> Unit): String {
-    /*LALAL*/
-    return ""
+    VideoPlayerHolder.stopAll()
+    AudioPlayer.stop()
+    val fileToSave = File.createTempFile(generateNewFileName("voice", "${RecorderInterface.extension}_", tmpDir), ".tmp", tmpDir)
+    fileToSave.deleteOnExit()
+    val path = fileToSave.absolutePath
+    filePath = path
+    val mrl = when {
+      desktopPlatform.isMac() -> "qtsound://"
+      desktopPlatform.isLinux() -> "pulse://"
+      desktopPlatform.isWindows() -> "dshow://"
+      else -> {
+        AlertManager.shared.showAlertMsg(generalGetString(MR.strings.voice_recording_not_supported))
+        return ""
+      }
+    }
+    val sout = ":sout=#transcode{vcodec=none,acodec=mp4a,ab=32,channels=1,samplerate=16000}:std{access=file,mux=mp4,dst=$path}"
+    val options = mutableListOf(sout, ":sout-avcodec-strict=-2")
+    if (desktopPlatform.isWindows()) {
+      options.add(":dshow-vdev=none")
+      options.add(":dshow-adev=")
+    }
+    RecorderInterface.stopRecording = { stop() }
+    progressJob = CoroutineScope(Dispatchers.Default).launch {
+      // Shared factory init may take a few seconds on first VLC use — progress shows 0 until recording starts
+      val p = vlcFactory.mediaPlayers().newMediaPlayer()
+      player = p
+      p.media().play(mrl, *options.toTypedArray())
+      recStartedAt = System.currentTimeMillis()
+      while (isActive) {
+        val ms = progress()
+        onProgressUpdate(ms, false)
+        if (ms != null && ms >= MAX_VOICE_MILLIS_FOR_SENDING) {
+          stop()
+          break
+        }
+        delay(50)
+      }
+    }.apply {
+      invokeOnCompletion { onProgressUpdate(realDuration(path), true) }
+    }
+    return path
   }
 
   override fun stop(): Int {
-    /*LALAL*/
-    return 0
+    val path = filePath ?: return 0
+    RecorderInterface.stopRecording = null
+    runCatching { player?.controls()?.stop() }
+    runCatching { player?.release() }
+    runBlocking { progressJob?.cancelAndJoin() }
+    progressJob = null
+    filePath = null
+    player = null
+    return (realDuration(path) ?: 0).also { recStartedAt = null }
   }
+
+  private fun progress(): Int? = recStartedAt?.let { (System.currentTimeMillis() - it).toInt() }
+
+  private fun realDuration(path: String): Int? = AudioPlayer.duration(path) ?: progress()
 }
 
 actual object AudioPlayer: AudioPlayerInterface {
-  private val player by lazy { AudioPlayerComponent().mediaPlayer() }
+  private val player by lazy { AudioPlayerComponent(vlcFactory).mediaPlayer() }
 
   override val currentlyPlaying: MutableState<CurrentlyPlayingState?> = mutableStateOf(null)
   private var progressJob: Job? = null
@@ -170,7 +228,7 @@ actual object AudioPlayer: AudioPlayerInterface {
   override fun duration(unencryptedFilePath: String): Int? {
     var res: Int? = null
     try {
-      val helperPlayer = AudioPlayerComponent().mediaPlayer()
+      val helperPlayer = AudioPlayerComponent(vlcFactory).mediaPlayer()
       helperPlayer.media().startPaused(unencryptedFilePath)
       res = helperPlayer.duration
       helperPlayer.stop()

apps/multiplatform/common/src/desktopMain/kotlin/chat/simplex/common/platform/VideoPlayer.desktop.kt

@@ -10,6 +10,7 @@ import uk.co.caprica.vlcj.media.VideoOrientation
 import uk.co.caprica.vlcj.player.base.*
 import uk.co.caprica.vlcj.player.component.CallbackMediaPlayerComponent
 import uk.co.caprica.vlcj.player.component.EmbeddedMediaPlayerComponent
+import uk.co.caprica.vlcj.player.component.MediaPlayerSpecs
 import java.awt.Component
 import java.awt.image.BufferedImage
 import java.io.File
@@ -32,7 +33,7 @@ actual class VideoPlayer actual constructor(
   override val duration: MutableState<Long> = mutableStateOf(defaultDuration)
   override val preview: MutableState<ImageBitmap> = mutableStateOf(defaultPreview)
 
-  val mediaPlayerComponent by lazy { runBlocking(playerThread.asCoroutineDispatcher()) { getOrCreatePlayer() } }
+  val mediaPlayerComponent by lazy { getOrCreatePlayer() }
   val player by lazy { mediaPlayerComponent.mediaPlayer() }
 
   init {
@@ -207,9 +208,9 @@ actual class VideoPlayer actual constructor(
 
     private fun initializeMediaPlayerComponent(): Component {
       return if (desktopPlatform.isMac()) {
-        CallbackMediaPlayerComponent()
+        CallbackMediaPlayerComponent(MediaPlayerSpecs.callbackMediaPlayerSpec().apply { withFactory(vlcFactory) })
       } else {
-        EmbeddedMediaPlayerComponent()
+        EmbeddedMediaPlayerComponent(MediaPlayerSpecs.embeddedMediaPlayerSpec().apply { withFactory(vlcFactory) })
       }
     }
 
@@ -277,7 +278,7 @@ actual class VideoPlayer actual constructor(
 
     private fun putPlayer(player: Component) = playersPool.add(player)
 
-    private fun getOrCreateHelperPlayer(): CallbackMediaPlayerComponent = helperPlayersPool.removeFirstOrNull() ?: CallbackMediaPlayerComponent()
+    private fun getOrCreateHelperPlayer(): CallbackMediaPlayerComponent = helperPlayersPool.removeFirstOrNull() ?: CallbackMediaPlayerComponent(MediaPlayerSpecs.callbackMediaPlayerSpec().apply { withFactory(vlcFactory) })
     private fun putHelperPlayer(player: CallbackMediaPlayerComponent) = helperPlayersPool.add(player)
   }
 }

apps/multiplatform/desktop/build.gradle.kts

@@ -73,6 +73,12 @@ compose {
           iconFile.set(project.file("src/jvmMain/resources/distribute/simplex.icns"))
           appCategory = "public.app-category.social-networking"
           bundleID = "chat.simplex.app"
+          infoPlist {
+            extraKeysRawXml = """
+              <key>NSMicrophoneUsageDescription</key>
+              <string>SimpleX needs microphone access to record voice messages</string>
+            """
+          }
           val identity = rootProject.extra["desktop.mac.signing.identity"] as String?
           val keychain = rootProject.extra["desktop.mac.signing.keychain"] as String?
           val appleId = rootProject.extra["desktop.mac.notarization.apple_id"] as String?

plans/2026-04-02-desktop-voice-recording.md

@@ -0,0 +1,39 @@
+# Desktop Voice Recording
+
+## Overview
+
+Implement voice recording on desktop using vlcj (already a dependency). The `RecorderNative` class is currently a stub. All UI is already in common code.
+
+## Files to modify
+
+1. `apps/multiplatform/common/src/desktopMain/kotlin/chat/simplex/common/platform/RecAndPlay.desktop.kt` — implement `RecorderNative`
+2. `apps/multiplatform/common/src/commonMain/kotlin/chat/simplex/common/views/chat/SendMsgView.kt` — remove desktop "in development" guard (line 317-318)
+3. `apps/multiplatform/desktop/build.gradle.kts` — add `NSMicrophoneUsageDescription` to macOS Info.plist
+
+## RecorderNative implementation
+
+Uses `MediaPlayerFactory` + `MediaPlayer` to capture from default microphone and transcode to AAC/m4a via VLC's sout chain.
+
+Platform-specific capture MRLs:
+- macOS: `qtsound://`
+- Linux: `pulse://`
+- Windows: `dshow://` with `:dshow-vdev=none :dshow-adev=`
+
+Transcode options: `vcodec=none,acodec=mp4a,ab=32,channels=1,samplerate=16000` — matches Android (mono, 16kHz, 32kbps AAC).
+
+Factory requires `--sout-avcodec-strict=-2` to enable FFmpeg's native AAC encoder.
+
+Progress tracked via elapsed time (VLC capture has no position API). Duration read via `AudioPlayer.duration()` after stop.
+
+Max duration: enforced by stopping recording after `MAX_VOICE_MILLIS_FOR_SENDING` (300,000 ms) in the progress coroutine.
+
+## macOS permission
+
+Add `NSMicrophoneUsageDescription` to Info.plist via Gradle `infoPlist` block.
+
+## What does NOT change
+
+- `RecorderInterface` (common)
+- `ComposeView.kt`, `ComposeVoiceView` — already handle voice preview/sending
+- Audio format — `.m4a` (matches Android)
+- All voice recording UI — already in common code