When playing rtsp stream, there is always a gray screen

[mzhs]

Hello, when using mobilevlckit library to play rtsp stream in ios development, pixel art gray screen and delay problems appear. How can I solve them? Thank you
code:
VLCMediaPlayer * player = [[VLCMediaPlayer alloc] initWithOptions:nil];
player.drawable=cell_cam.playView;
VLCMedia *media=[VLCMedia mediaWithURL:[NSURL URLWithString:url]];
player.media =media;
[player play];

[mzhs]

It's not always a gray screen, it happens from time to time