It is NOT only primarly the programming language determining but also the useable code base and at most libraries.
In your case of streaming your really should know and take a deep dive into
ffmpeg which is a proven and well aknowled library which handles RTP/RTSP and MPEG-2 and has also support for a lot of other features. My guess is, that you will use it because it does the job.
The performance differences between the languages are minimal, mostly depending on specialties.