vlcj snapshot

[buxx8020882]

i am doing something an this: two people talk with each other through voice(audio),no video display ,but they also want to have a snapshot sometimes,i am using vlcj now ,to open the audio device ,i use mediaplayer.playmedia("dshow://"),but when i use above like this mediaplayer.playmedia("dshow://"，":sout=#transcdoe{vcodec...,acodec..}"),when i snapshot ,it is failed,why

[buxx8020882]

ding,can anybody answer?