smeared/corrupted capture of RTSP streams - opencv

Question

i've using emgu cv 2.4.10 to create a RTSP stream viewer that will eventually be used with IP cameras. as i don't have the camera/s as yet, i'm testing using VLC (the windows GUI) to create the stream from a video file.
:sout=#duplicate{dst=rtp{sdp=rtsp://:8554/stream},dst=display} :sout-all :sout-keep
i'm doing this all testing on localhost.
here's my capture code:
private void ProcessFrame(object sender, EventArgs arg) {
try {
frame = _capture.QueryFrame();
pictureBox1.Image = frame.ToBitmap();
}
catch (Exception ex) {
MessageBox.Show(ex.Message.ToString());
}
}
this method is called using this eventhandler:
_capture = new Capture("rtsp://localhost:8554/stream");
Application.Idle += ProcessFrame;
_capture.Start();
the capture is corrupted with random occurrences of "smearing" that always occurs in the lower portion of the frame:
i've seen several others online have reported this problem as recently as last december but no solution has been found or that would work for me:
http://workingwithcomputervision.blogspot.co.uk/2012/06/issues-with-opencv-and-rtsp.html
EMGU QueryFrame returns "streaky" Image over RTSP
http://www.emgu.com/forum/viewtopic.php?f=7&t=4882&p=10110&hilit=rtsp#p10069
to narrow down the problem, i've run ffplay from the commandline and the capture is perfect. i've run another instance of VLC to capture the RTSP stream and it displays perfectly. so this is clearly a problem in open cv/emgu cv.
on a whim, i changed VLC to stream using HTTP.
:sout=#duplicate{dst=http{mux=ffmpeg{mux=flv},dst=:8080/stream},dst=display} :sout-all :sout-keep
this displays fine in my code, but at a noticeably lower frame rate that won't work for my application. i'd really appreciate any tips to fixing this problem. thanks.

Answer 1

I don't know if you solved your problem but i suggest you not to make your process in application.idle event. Instead, use thread. Create another thread and make your proccess in it. Example c# code:
Thread t = new Thread(new ThreadStart(()=>{ while(true) {frame = _capture.QueryFrame();
pictureBox1.Image = frame.ToBitmap();}})); t.IsBackGround = true; t.Start();