I use it just for audio.

But eventually some terminal reinvites offering video.

I don't want to refuse the request but just disable RTP proxying for video as my employer has limited bandwidth and want to reserve it only for audio.

So I checked the rtpengine module documentation but it seems there is no way to restrict RTP proxying to be performed only for m=audio.

I tried some things like

    replace_body("^m=video [0-9]+", "m=video 0");

and
    subst_body('/^m=video [0-9]+ /m=video 0 /');

and 

    msg_apply_changes();

but still the RTP proxying  for video is set up.

Any hints on how to solve this?