Pipeline using mpegtsmux hang when source have no audio

My pipeline hang when i tried to use a source with no audio. Other source with still audio works. Here is my pipeline:
dot.txt (40.3 KB)

I also want to send audio over rtsp, so does the data muxed with mpegtsmux can be send to udp sink?

gs.log (302.7 KB)
Here is some log, it seems somehow the pipeline is setted to pause state when there is no audio for mpegtsmux.

Currently i am working around by using a audio mixer to mix a fakesrc to make sure it always have audio. There must be a better way right?