The streamid format that starts with #!: is recommended in the SRT
specs but it usually causes trouble where you're limited in the
use of such characters. Some hardware devices will not accept such
streamids.
The alternative format is simpler and has the form
[resource](,token:[token])?(,mode:[mode])?
token and mode are optional. mode can have the values "publish" or
"request". If mode is not provided, a value of "request" is
assumed.
