sendMetadata is not working

[ilyasmez]

Describe the bug
Can't send a metadata.

To Reproduce
Try sending some metadata using

rtcEngine.sendMetadata('test')

The metadata is not sent to the other users and this error is shown in the console:

E/flutter (29530): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: PlatformException(7, not initialized, null, null)
E/flutter (29530): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:582:7)
E/flutter (29530): #1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:159:18)
E/flutter (29530): <asynchronous suspension>
E/flutter (29530): #2      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:332:12)
E/flutter (29530): #3      RtcEngine._invokeMethod (package:agora_rtc_engine/src/rtc_engine.dart:35:27)
E/flutter (29530): #4      RtcEngine.sendMetadata (package:agora_rtc_engine/src/rtc_engine.dart:576:12)

Expected behavior
The metadata is being sent successfully, and caught by the other users using the metadataReceived event listener.

Smartphone (please complete the following information):

• Device: Pixel 4 (physical), and a few other emulated devices.
• OS: Android 11
• Browser [e.g. stock browser, safari]

Additional context
Using agora_rtc_engine: 3.2.1

[LichKing-2234]

PlatformException(7, not initialized, null, null)

you should init engine first

[ilyasmez]

PlatformException(7, not initialized, null, null)
you should init engine first

Hi @LichKing-2234, thank you for the reply.

I'm initializing the engine before anything else:

_engine = await RtcEngine.create(AGORA_APP_ID);
await _engine.enableVideo();
await _engine.setChannelProfile(ChannelProfile.LiveBroadcasting);
await _engine.setClientRole(ClientRole.Audience);

I don't think this is the problem, because I try to send the metadata during an active live streaming.

[LichKing-2234]

Sorry, my mistake, you should call registerMediaMetadataObserver first.

[ilyasmez]

Great thank you @LichKing-2234, the error is gone now.
But the metadata is still not received by the other users. The string is really short, so it's probably not the due to the size.
I'm trying to send the metadata from the broadcaster to the audience, in case this matters.

This is a simplified snippet:

RtcEngine _engine;

Future<void> initializeAgora() async {
  _engine = await RtcEngine.create(AGORA_APP_ID);

  _engine.setEventHandler(RtcEngineEventHandler(
    metadataReceived: (buffer, _, __) {
      print('Metadata received $buffer');
    },
  ));

  await _engine.registerMediaMetadataObserver();
} 

Future<void> sendAgoraMetadata() async {
  await _engine.sendMetadata( 'test');
} 

And sendAgoraMetadata is called during the video call.
The "Metadata received" is never printed for any user.

[LichKing-2234]

maybe you should call setMaxMetadataSize first

[ilyasmez]

That actually solves the issue (surprisingly), thank you very much @LichKing-2234.
I've called await _engine.setMaxMetadataSize(1024); right after registering the observer and everything worked as expected.
I think this should still be fixed on the SDK level as well, because in the docs it says that the default value is 1024, so my call should be unnecessary (but apparently it's not).
I'll look deeper into this issue if I find time this weekend.

[elricym]

I find the same issue which I can't receive any metadata sent. Could you tell me the solution about this? Thank you.

[hovanhung98hust]

Sorry, my mistake, you should call registerMediaMetadataObserver first.

this work for me. Thanks

[hovanhung98hust]

r registering the ob

i have successfully sentMetadata but still get nothing in metadataReceived in _rtcEngine?.setEventHandler. Can you make me your sample code?
@OverRide
void initState() {
super.initState();
initPlatformState();
}

// Init the app
Future initPlatformState() async {
await [Permission.camera, Permission.microphone].request();

// Create RTC client instance
_rtcEngine = await RtcEngine.create(CallConst.AgoraAppId);
// Define event handling logic

_rtcEngine?.setEventHandler(
  RtcEngineEventHandler(
    joinChannelSuccess: (String channel, int uid, int elapsed) {
      injector<SnackBarBloc>().add(ShowSnackbarEvent(
          type: SnackBarType.success, content: 'joinChannelSuccess: $uid'));
      setState(() {
        _joined = true;
      });
    },
    userJoined: (int uid, int elapsed) {
      injector<SnackBarBloc>().add(ShowSnackbarEvent(
          type: SnackBarType.success, content: 'userJoined: $uid'));
      setState(() {
        _remoteUid = uid;
      });
    },
    metadataReceived: (String data, int uid, int timeStampMs) {
      injector<SnackBarBloc>().add(ShowSnackbarEvent(
        content: '1 - $data | $uid',
        type: SnackBarType.success,
      ));
    },
    streamMessage: (int uid, int streamId, String data) {
      injector<SnackBarBloc>().add(ShowSnackbarEvent(
        content: '2 - $data | $uid',
        type: SnackBarType.success,
      ));
    },
    userOffline: (int uid, UserOfflineReason reason) {
      LOG.d('LogTestLive: userOffline1: ${reason.toString()}');
      LOG.d('LogTestLive: userOffline2: $uid');
      injector<SnackBarBloc>().add(ShowSnackbarEvent(
          type: SnackBarType.success,
          content: 'userOffline: ${reason.toString()}'));
      CommonUtil.copyClipboard('userOffline: $uid', showSnackbar: false);
      setState(() {
        _remoteUid = 0;
      });
    },
  ),
);
// Enable video

await _rtcEngine?.enableVideo();
if (!_isHostLive) {
  await _rtcEngine?.setEnableSpeakerphone(true);
}

await _rtcEngine?.joinChannel(Token, CHANNEL_DEMO_LIVE, null, idUserWatch);
// Set channel profile as livestreaming
await _rtcEngine?.setChannelProfile(ChannelProfile.LiveBroadcasting);
// Set user role as broadcaster
await _rtcEngine?.setClientRole(
    _isHostLive ? ClientRole.Broadcaster : ClientRole.Audience);
await _rtcEngine?.registerMediaMetadataObserver();
await _rtcEngine?.setMaxMetadataSize(1024);

}

void _sendMessageData() async {
try {
  await _rtcEngine?.sendMetadata(_textController.text);
  _textController.text = '';
  injector<SnackBarBloc>().add(ShowSnackbarEvent(
      type: SnackBarType.success, content: '_sendMessageData'));
} catch (e) {
  injector<SnackBarBloc>().add(ShowSnackbarEvent(
      type: SnackBarType.error, content: '_sendMessageData'));
}

}

[Miko2x]

@hovanhung98hust same to me, have you found the solution?
I'm using version 5.3.1 for the agora_rtc_engine.
CC: @littleGnAl

[littleGnAl]

@Miko2x Can you please raise a new issue for your case, thanks.

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