Garbled image problem on usb_cam

I am testing usb_cam_node with a usb camera, when I use the follow launch file, everything is ok, but when I change pixel_format to **mjpeg**, the video become garbled   `v4l2-ctl --list-format-ext -d /dev/video0` output: ioctl: VIDIOC_ENUM_FMT Index : 0 Type : Video Capture Pixel Format: 'MJPG' (compressed) Name : MJPEG Size: Discrete 1920x1080 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 1280x720 Interval: Discrete 0.017s (60.000 fps) Size: Discrete 1024x768 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 640x480 Interval: Discrete 0.008s (120.101 fps) Size: Discrete 800x600 Interval: Discrete 0.017s (60.000 fps) Size: Discrete 1280x1024 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 320x240 Interval: Discrete 0.008s (120.101 fps) Index : 1 Type : Video Capture Pixel Format: 'YUYV' Name : YUV 4:2:2 (YUYV) Size: Discrete 1920x1080 Interval: Discrete 0.167s (6.000 fps) Size: Discrete 1280x720 Interval: Discrete 0.111s (9.000 fps) Size: Discrete 1024x768 Interval: Discrete 0.167s (6.000 fps) Size: Discrete 640x480 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 800x600 Interval: Discrete 0.050s (20.000 fps) Size: Discrete 1280x1024 Interval: Discrete 0.167s (6.000 fps) Size: Discrete 320x240 Interval: Discrete 0.033s (30.000 fps) And the error message: [mjpeg @ 0x223e460] overread 8 [mjpeg @ 0x223e460] overread 8 [mjpeg @ 0x223e460] error count: 68 [mjpeg @ 0x223e460] error y=38 x=1 [mjpeg @ 0x223e460] error count: 64 [mjpeg @ 0x223e460] error y=34 x=1 [mjpeg @ 0x223e460] error count: 68 [mjpeg @ 0x223e460] error y=40 x=4 [mjpeg @ 0x223e460] error count: 64 [mjpeg @ 0x223e460] error y=42 x=1 [mjpeg @ 0x223e460] error count: 64 [mjpeg @ 0x223e460] error y=31 x=0 [mjpeg @ 0x223e460] error count: 64 [mjpeg @ 0x223e460] error y=30 x=37 [mjpeg @ 0x223e460] overread 8 My testing enviroment: Ubuntu 14.04.3, ROS indigo I've search almost the whole web, can't figure it out, please help! Thanks