Video quality in liocde

I want to inquiry a video quality issue.
issue description:
I just connect two user video with erizo core module(MCU) of Licode.
But the video quality is not good (it is very fuzzy)when the network become to poor. (the bitrate about 100 kb/s)
one moment late, the video quality can re-comeback to normally.

of course, I think this issue is not in Licode.
I guess the reason is webrtc doing something for vedio quality while bad network.

I just hope , do you give some comment to handle this case ?
maybe you also face video quality in Licode when use webrtc interface.

Thanks in advance.–

Best regards

                                                           Huaya Zuo