when I type tcp/h264://192.168.0.100:8000/,
filestream automatically add the vvvv path, my string looks like: C:\Program Files (x86)\vvvv_45beta31.2_x86\tcp/h264://192.168.0.100:8000/
Well this is by design. The Filename pin says it wants a file name, therefor the upstream IO box tries to return a file name. If the Filename can deal with connection strings like you posted (which are clearly not file names), it shouldn’t enforce that property. Instead it should be renamed to “Connection String” or something like that and be able to deal with normal strings.
Anyway, in your case put a node like + (String) between the pin and your IO box to circumvent the subtype propagation and you should at least see your connection string coming in on the Filename pin - I’ve no idea if it will work though.