PlatformAudio: IsDeviceSelectionSupported capability

Runtime/Scripts/PlatformAudio.cs

@@ -67,34 +67,7 @@ public struct AudioDevice
     /// 2. Optionally enumerate and select devices
     /// 3. Create audio tracks using PlatformAudioSource
     /// 4. Remote audio automatically plays through speakers
-    /// </summary>
-    /// <example>
-    /// <code>
-    /// // Create PlatformAudio (enables ADM)
-    /// var platformAudio = new PlatformAudio();
-    ///
-    /// // Enumerate devices
-    /// var (recording, playout) = platformAudio.GetDevices();
-    /// foreach (var device in recording)
-    ///     Debug.Log($"Mic {device.Index}: {device.Name}");
-    ///
-    /// // Select devices (no-op on Android/iOS; routing there is governed by the OS).
-    /// // Use the uint overload for quick index-based selection, or the string overload
-    /// // with a GUID from GetDevices() to persist a stable selection across hot-plug.
-    /// platformAudio.SetRecordingDevice(0);
-    /// platformAudio.SetPlayoutDevice(0);
-    ///
-    /// // Create audio source and track
-    /// var source = new PlatformAudioSource(platformAudio);
-    /// var track = LocalAudioTrack.CreateAudioTrack("microphone", source, room);
-    ///
-    /// // Publish track
-    /// await room.LocalParticipant.PublishTrack(track, options);
-    ///
-    /// // Dispose when done
-    /// platformAudio.Dispose();
-    /// </code>
-    /// </example>
+
     public sealed class PlatformAudio : IDisposable
     {
         internal readonly FfiHandle Handle;
@@ -111,6 +84,18 @@ public sealed class PlatformAudio : IDisposable
         /// </summary>
         public int PlayoutDeviceCount => _info.PlayoutDeviceCount;
 
+        /// <summary>
+        /// Whether per-device selection is honored on this platform.
+        ///
+        /// True on desktop (Windows, macOS, Linux), where <see cref="SetRecordingDevice(string)"/>
+        /// and <see cref="SetPlayoutDevice(string)"/> select the device. False on iOS/Android,
+        /// where audio routing is controlled by the OS (AVAudioSession / AudioManager); the
+        /// selection methods are accepted but have no effect there.
+        ///
+        /// Use this to decide whether to present a device-picker UI.
+        /// </summary>
+        public bool IsDeviceSelectionSupported => _info.DeviceSelectionSupported;
+
         /// <summary>
         /// Creates a new PlatformAudio instance, enabling the platform ADM.
         ///
@@ -149,6 +134,11 @@ public PlatformAudio()
 
         /// <summary>
         /// Gets the lists of available recording and playout devices.
+        ///
+        /// On Android and iOS this typically reports a single "default" device, and
+        /// selecting a device has no effect (see <see cref="IsDeviceSelectionSupported"/>):
+        /// audio routing is governed by the OS. The list is informational there; prefer
+        /// gating any device-picker UI on <see cref="IsDeviceSelectionSupported"/>.
         /// </summary>
         /// <returns>
         /// A tuple containing:
@@ -198,6 +188,9 @@ public PlatformAudio()
         /// Convenience wrapper around <see cref="SetRecordingDevice(string)"/> that looks
         /// up the GUID from <see cref="GetDevices"/>. Prefer the GUID overload for code
         /// that persists a selection — indices can shift when devices are added/removed.
+        ///
+        /// No-op on Android/iOS, same as <see cref="SetRecordingDevice(string)"/>
+        /// (see <see cref="IsDeviceSelectionSupported"/>).
         /// </summary>
         /// <param name="index">Device index from GetDevices().Recording</param>
         /// <exception cref="InvalidOperationException">
@@ -215,10 +208,10 @@ public void SetRecordingDevice(uint index)
         /// <summary>
         /// Sets the recording device (microphone) by device ID (GUID).
         ///
-        /// On Android and iOS this is a no-op in the native ADM: input routing is
-        /// governed by the OS (AVAudioSession on iOS, AudioManager on Android) and
-        /// the call is acknowledged but ignored. The method is still safe to call,
-        /// and the response carries no error.
+        /// On Android and iOS this is a no-op (see <see cref="IsDeviceSelectionSupported"/>):
+        /// input routing is governed by the OS (AVAudioSession on iOS, AudioManager on
+        /// Android) and the call is acknowledged but ignored. The method is still safe to
+        /// call, and the response carries no error.
         /// </summary>
         /// <param name="deviceId">Device ID/GUID from GetDevices().Recording[i].Guid</param>
         /// <exception cref="InvalidOperationException">
@@ -245,6 +238,9 @@ public void SetRecordingDevice(string deviceId)
         /// Convenience wrapper around <see cref="SetPlayoutDevice(string)"/> that looks
         /// up the GUID from <see cref="GetDevices"/>. Prefer the GUID overload for code
         /// that persists a selection — indices can shift when devices are added/removed.
+        ///
+        /// No-op on Android/iOS, same as <see cref="SetPlayoutDevice(string)"/>
+        /// (see <see cref="IsDeviceSelectionSupported"/>).
         /// </summary>
         /// <param name="index">Device index from GetDevices().Playout</param>
         /// <exception cref="InvalidOperationException">
@@ -262,10 +258,10 @@ public void SetPlayoutDevice(uint index)
         /// <summary>
         /// Sets the playout device (speaker/headphones) by device ID (GUID).
         ///
-        /// On Android and iOS this is a no-op in the native ADM: output routing is
-        /// governed by the OS (AVAudioSession on iOS, AudioManager on Android) and
-        /// the call is acknowledged but ignored. The method is still safe to call,
-        /// and the response carries no error.
+        /// On Android and iOS this is a no-op (see <see cref="IsDeviceSelectionSupported"/>):
+        /// output routing is governed by the OS (AVAudioSession on iOS, AudioManager on
+        /// Android) and the call is acknowledged but ignored. The method is still safe to
+        /// call, and the response carries no error.
         /// </summary>
         /// <param name="deviceId">Device ID/GUID from GetDevices().Playout[i].Guid</param>
         /// <exception cref="InvalidOperationException">