RTSP stream stops after 30 secods when using TCP

I am streaming video over RTSP using FFmpegFrameGrabber. If I do not specify UDP vs TCP it seems that the connection is stable and but I sometimes see artifiacts and distortion in the image I am receiving from the camera. However, if I specify TCP as the rtsp_transport, the image is much better with no artifacts. However, after about 30 seconds, when I call Frame.grabImage(), it returns null. At this point, I can call FFmpegFrameGrabber.stop(), followed by FFmpegFrameGrabber.start(), and the streaming of frames will continue for another 30 seconds.

I see the same behavior using ffplay from the command line. I have also discovered that if I set the -err_detect flag to ignore_err, ffplay will continue streaming frames indefinitely and the problem goes away.

ffplay rtsp://192.168.1.254/xxx.mov -rtsp_transport tcp -err_detect ignore_err

However, setting the "err_detect" flag does not seem to make any difference using javacv. Here is the code I am using:

FFmpegLogCallback.set()
val grabber = FFmpegFrameGrabber(url)
grabber.format = "rtsp"
grabber.videoCodecName = "h264_mediacodec"
grabber.options["rtsp_transport"] = "tcp"  //this stops artifacts and distortion but only runs for 30 seconds then stops
grabber.options["err_detect"] = "ignore_err" //this doesn't seem to make any difference as it does using ffplay from the command line 
grabber.frameRate = 30.0
grabber.sampleRate = 30
grabber.start() 
while (alive) {
    val frame = grabber.grabImage()
    if (frame == null) {
        grabber.stop()
        grabber.start()
    } else {
        //process frame 
    }
}