Sets the GStreamer pipeline used to encode recordings. It follows the syntax used for gst-launch. The pipeline should have an unconnected sink pad where the recorded video is recorded. It will normally have a unconnected source pad; output from that pad will be written into the output file. However the pipeline can also take care of its own output - this might be used to send the output to an icecast server via shout2send or similar. When unset or set to an empty value, the default pipeline will be used. This is currently 'vp8enc quality=8 speed=6 threads=%T ! queue ! webmmux' and records to WEBM using the VP8 codec. %T is used as a placeholder for a guess at the optimal thread count on the system.
