fix: audio play bug for ios safari. (#285)

* fix: audio play bug for ios safari. (WIP).

* chore: Repair and can pop up the playback prompt dialog box correctly.

* chore: add AudioContext to reduce playback delay.

lib/src/track/remote/audio.dart

@@ -1,4 +1,5 @@
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
+import 'package:livekit_client/src/internal/events.dart';
 
 import '../../proto/livekit_models.pb.dart' as lk_models;
 import '../../types/other.dart';
@@ -28,10 +29,16 @@ class RemoteAudioTrack extends RemoteTrack
   Future<bool> start() async {
     final didStart = await super.start();
     if (didStart) {
-      // web support
-      audio.startAudio(getCid(), mediaStreamTrack);
-      if (_deviceId != null) {
-        audio.setSinkId(getCid(), _deviceId!);
+      try {
+        // web support
+        await audio.startAudio(getCid(), mediaStreamTrack);
+        if (_deviceId != null) {
+          audio.setSinkId(getCid(), _deviceId!);
+        }
+      } catch (e) {
+        if (e.toString().startsWith('NotAllowedError')) {
+          events.emit(AudioPlaybackFailed(track: this));
+        }
       }
     }
     return didStart;

lib/src/track/web/_audio_api.dart

@@ -1,6 +1,6 @@
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
 
-void startAudio(String id, rtc.MediaStreamTrack stream) {
+Future<dynamic> startAudio(String id, rtc.MediaStreamTrack stream) async {
   // do nothing
 }
 
@@ -8,6 +8,10 @@ void stopAudio(String id) {
   // do nothing
 }
 
+Future<bool> startAllAudioElement() async {
+  return true;
+}
+
 void setSinkId(String id, String deviceId) {
   // do nothing
 }

lib/src/track/web/_audio_html.dart

@@ -1,6 +1,7 @@
 import 'dart:html' as html;
 import 'dart:js_util' as jsutil;
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
+import 'package:js_bindings/js_bindings.dart' as js_bindings;
 
 // ignore: implementation_imports
 import 'package:dart_webrtc/src/media_stream_track_impl.dart'; // import_sorter: keep
@@ -8,10 +9,14 @@ import 'package:dart_webrtc/src/media_stream_track_impl.dart'; // import_sorter:
 const audioContainerId = 'livekit_audio_container';
 const audioPrefix = 'livekit_audio_';
 
-void startAudio(String id, rtc.MediaStreamTrack track) {
+js_bindings.AudioContext _audioContext = js_bindings.AudioContext();
+Map<String, html.Element> _audioElements = {};
+
+Future<dynamic> startAudio(String id, rtc.MediaStreamTrack track) async {
   if (track is! MediaStreamTrackWeb) {
     return;
   }
+
   final elementId = audioPrefix + id;
   var audioElement = html.document.getElementById(elementId);
   if (audioElement == null) {
@@ -19,6 +24,7 @@ void startAudio(String id, rtc.MediaStreamTrack track) {
       ..id = elementId
       ..autoplay = true;
     findOrCreateAudioContainer().append(audioElement);
+    _audioElements[id] = audioElement;
   }
 
   if (audioElement is! html.AudioElement) {
@@ -27,6 +33,16 @@ void startAudio(String id, rtc.MediaStreamTrack track) {
   final audioStream = html.MediaStream();
   audioStream.addTrack(track.jsTrack);
   audioElement.srcObject = audioStream;
+  return audioElement.play();
+}
+
+Future<bool> startAllAudioElement() async {
+  for (final element in _audioElements.values) {
+    if (element is html.AudioElement) {
+      await element.play();
+    }
+  }
+  return _audioContext.state == js_bindings.AudioContextState.running;
 }
 
 void stopAudio(String id) {
@@ -35,6 +51,7 @@ void stopAudio(String id) {
     if (audioElement is html.AudioElement) {
       audioElement.srcObject = null;
     }
+    _audioElements.remove(id);
     audioElement.remove();
   }
 }