Can Centova Cast be installed without shell/SSH/root access?
Can Centova Cast be installed via FTP/web only, without shell/SSH access?
Can Centova Cast be installed without root privileges?
This is not practical (and thus not supported) due to the limitations that result from a web-based installation. Root access via the console or SSH is required to install Centova Cast.
It is important to note that Centova Cast is not "just another PHP script" -- it is a control panel system that is responsible for launching and managing external processes under separate user accounts, and as such requires special installation procedures to ensure that those processes are launched correctly.
With a strictly FTP-based installation, you would encounter problems such as streams crashing when the web server is restarted, security issues caused by running the streams under the web server's UNIX user account, configuration files being readable by the web server and possibly published under your web root, and so-on. You would also be unable to setup FTP accounts for your clients to login and upload their media.
We are aware that some competitors' products implement clunky workarounds for these issues (such as controlling streams on a delay from a cron job), however we do not feel that these are acceptable, practical solutions for a professional stream hosting provider and thus have not implemented such workarounds in Centova Cast.