Logitech Rally supports Full HD (1080p) video at 30 frames per second. If you're having trouble getting HD-quality video with your camera, the problem is most likely with your video-calling client software or the environment in which you're using your device. Please refer to your video client's documentation for recommendations about optimal HD quality.
In addition, check the following:
USB bandwidth — (ex. using many active USB devices at the same time)
CPU utilization — (ex. file transfers, streaming, checking email, antivirus scanning)
Network bandwidth — your internet connection download speed should be at least 3 Mbps