Issue playing MxPEG video stream

We are attempting to play a stream of MxPEG from a Mobotix camera in our Flutter app. The package we are using (flutter_vlc_player https://pub.dev/packages/flutter_vlc_player) uses MobileVLCKit (3.3.17) and mobile_ffmpeg_audio (4.4LTS).

We have passed the --avformat-format=mxg flag to our VLCPlayer, and are using the URL: "http://username:password@url:port/control/faststream.jpg?stream=MxPEG", but it is not playing any audio. On Android, the video and audio play as expected, so we wonder whether it's a security issue in iOS similar to how MxPEG plays a MJPEG on the web.

Passing --avformat-format=mxg "http://username:password@url:port/control/faststream.jpg?stream=MxPEG" to Terminal and running it in the VLC app on MacOS works as expected also, so as far as we can see, it's an iOS-specific issue.

Should we expect MxPEG to be supported on iOS, or is this a known issue?