The parameter media_id in start|stop_play_wav, start|stop_record_wav, start_speech_synth, send_dtmf etc must be optional. If not present, the media function should affect all audio media streams.
start_record_wav (cannot be applied to all audio media because they would write to the same file (well, we could mix the audio from multiple media streams and write to the same wav file but I don't see a testing scenario where this would be useful)): OK
stop_record_wav: OK
start_play_wav: OK
stop_play_wav: OK
start_fax (if is_sender: can start to all media endpoints. if not is_sender: can start only to a single media endpoint): OK
The parameter media_id in start|stop_play_wav, start|stop_record_wav, start_speech_synth, send_dtmf etc must be optional. If not present, the media function should affect all audio media streams.