[ICA-H610] Why did the screen blank or very slow video after I audio is enabled.

Your connection to the device does not have enough bandwidth to support a higher frame rate for the streamed image size. Try reducing the video streaming size to 176x112 or 352x240 and/or disabling audio.
Audio will consume 32 kbps. Disable audio to improve video. Your Internet connection may not have enough bandwidth to support streaming audio from the device.