if( muxer ) [subOptions addObject:[NSString stringWithFormat:@"muxer=%@", muxer]];
if( destination ) [subOptions addObject:[NSString stringWithFormat:@"dst=%@", destination]];
if( sdp ) [subOptions addObject:[NSString stringWithFormat:@"sdp=%@", sdp]];
if( muxer ) [subOptions addObject:[NSString stringWithFormat:@"muxer=%@", muxer]];
if( destination ) [subOptions addObject:[NSString stringWithFormat:@"dst=%@", destination]];
if( sdp ) [subOptions addObject:[NSString stringWithFormat:@"sdp=%@", sdp]];