Set a media's vod muxer.
        @param psz_name: the media to work on.
        @param psz_mux: the new muxer.
        @return: 0 on success, -1 on error.

def vlm_set_mux(self, psz_name, psz_mux):
        '''Set a media's vod muxer.
        @param psz_name: the media to work on.
        @param psz_mux: the new muxer.
        @return: 0 on success, -1 on error.
        '''
        return libvlc_vlm_set_mux(self, str_to_bytes(psz_name), str_to_bytes(psz_mux))