fix: Maintain video quality for live streaming.

.changes/maintain-video-quality-for-live-streaming

@@ -0,0 +1 @@
+patch type="fixed" "Maintain video quality for live streaming via new liveStreaming capture option"

example/lib/pages/prejoin.dart

@@ -60,6 +60,8 @@ class _PreJoinPageState extends State<PreJoinPage> {
   MediaDevice? _selectedVideoDevice;
   MediaDevice? _selectedAudioDevice;
   VideoParameters _selectedVideoParameters = VideoParametersPresets.h720_169;
+  int _videoBitrate = 3 * 1000 * 1000;
+  bool _liveStreaming = true;
 
   @override
   void initState() {
@@ -183,6 +185,7 @@ class _PreJoinPageState extends State<PreJoinPage> {
       _videoTrack = await LocalVideoTrack.createCameraTrack(CameraCaptureOptions(
         deviceId: _selectedVideoDevice!.deviceId,
         params: _selectedVideoParameters,
+        liveStreaming: _liveStreaming,
       ));
       await _videoTrack!.start();
     }
@@ -203,8 +206,8 @@ class _PreJoinPageState extends State<PreJoinPage> {
 
     try {
       //create new room
-      const cameraEncoding = VideoEncoding(
-        maxBitrate: 5 * 1000 * 1000,
+      final cameraEncoding = VideoEncoding(
+        maxBitrate: _videoBitrate,
         maxFramerate: 30,
       );
 
@@ -449,6 +452,57 @@ class _PreJoinPageState extends State<PreJoinPage> {
                       ),
                     ),
                   ),
+                if (_enableVideo)
+                  Padding(
+                    padding: const EdgeInsets.only(bottom: 5),
+                    child: Row(
+                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                      children: [
+                        const Text('Live Streaming:'),
+                        Switch(
+                          value: _liveStreaming,
+                          onChanged: (value) async {
+                            setState(() {
+                              _liveStreaming = value;
+                            });
+                            await _changeLocalVideoTrack();
+                            if (mounted) setState(() {});
+                          },
+                        ),
+                      ],
+                    ),
+                  ),
+                if (_enableVideo)
+                  Padding(
+                    padding: const EdgeInsets.only(bottom: 25),
+                    child: Row(
+                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                      children: [
+                        const Text('Video Bitrate:'),
+                        SizedBox(
+                          width: 140,
+                          height: 40,
+                          child: TextFormField(
+                            initialValue: (_videoBitrate ~/ 1000).toString(),
+                            keyboardType: TextInputType.number,
+                            textAlign: TextAlign.right,
+                            decoration: const InputDecoration(
+                              isDense: true,
+                              contentPadding: EdgeInsets.symmetric(horizontal: 12, vertical: 8),
+                              border: OutlineInputBorder(),
+                              suffixText: 'kbps',
+                            ),
+                            onChanged: (value) {
+                              final kbps = int.tryParse(value);
+                              if (kbps != null && kbps > 0) {
+                                _videoBitrate = kbps * 1000;
+                              }
+                            },
+                          ),
+                        ),
+                      ],
+                    ),
+                  ),
                 Padding(
                   padding: const EdgeInsets.only(bottom: 5),
                   child: Row(

lib/src/participant/local.dart

@@ -594,6 +594,10 @@ class LocalParticipant extends Participant<LocalTrackPublication> {
   }
 
   DegradationPreference getDefaultDegradationPreference(LocalVideoTrack track) {
+    // keep both framerate and resolution for live streaming.
+    if (track.currentOptions.liveStreaming == true) {
+      return DegradationPreference.maintainFramerateAndResolution;
+    }
     // a few of reasons we have different default paths:
     // 1. without this, Chrome seems to aggressively resize the SVC video stating `quality-limitation: bandwidth` even when BW isn't an issue
     // 2. since we are overriding contentHint to motion (to workaround L1T3 publishing), it overrides the default degradationPreference to `balanced`

lib/src/track/options.dart

@@ -62,12 +62,14 @@ class CameraCaptureOptions extends VideoCaptureOptions {
     double? maxFrameRate,
     VideoParameters params = VideoParametersPresets.h720_169,
     this.stopCameraCaptureOnMute = true,
+    bool? liveStreaming,
     TrackProcessor<VideoProcessorOptions>? processor,
   }) : super(
           params: params,
           deviceId: deviceId,
           maxFrameRate: maxFrameRate,
           processor: processor,
+          liveStreaming: liveStreaming,
         );
 
   CameraCaptureOptions.from({required VideoCaptureOptions captureOptions})
@@ -231,11 +233,15 @@ abstract class VideoCaptureOptions extends LocalTrackOptions {
   /// A processor to apply to the video track.
   final TrackProcessor<VideoProcessorOptions>? processor;
 
+  /// Maintain high framerate and bitrate.
+  final bool? liveStreaming;
+
   const VideoCaptureOptions({
     this.params = VideoParametersPresets.h540_169,
     this.deviceId,
     this.maxFrameRate,
     this.processor,
+    this.liveStreaming,
   });
 
   @override