Current WebRTC implamentations use Opus and VP8 codecs:
.The Opus codec is audio codec developed by IETF (codec IETF working group) to be suitable for interactive audio over the internet. OPUS extended from other two audio codecs: SILK, and CELT. OPUS can adapt seamlessly to high and low bandwidth. OPUS has very low algorithmic delay (26.5 ms – 5 ms). It supports constant and variable bitrate from 6 kbit/s to 510 kbit/s.
The VP8 is video codec developed by Google. It is extended from VP7. The bitrate varies from 100 to 2000+ kbit/s depending on the size and the quality of the video. Then VP9 came to reduce the bitrate by 50% compared with VP8 with same video quality.
Note: If the hardware is able to capture high quality streams, the CPU and the bandwidth must be able to preserve this.