Wowza can be installed in a different path, but it would need to be maintained by hand and you would need to modify certain symlinks found in /usr/local/ (WowzaStreamingEngine) and in /usr/bin/ (WowzaStreamingEngined and WowzaStreamingEngineManagerd). They would need to be modified to point to the relevant physical files if they are not in their normal install paths. There may be other changes required within various support scripts etc. We would not recommend this, purely for support reasons. Can I ask why you wish the Wowza installation to be moved to your public_html directory? Is it so you can access certain Wowza files via a web browser? It may be easier and certainly less distruptive to create symlinks in your public_html to point to the native paths that Wowza is installed in.
because I took a lot for uploading video or mp3 files for VOD, with web php, because if outside public_html inaccessible, is there any other way or no API her for play video mp3 etc which are outside usr/local/WowzaStreamingEngine/content?
if I want to change its directory which parts should I edit? or how to determine when the first installation when I want to decide where I want to install it. because I follow this tutorial there is no part where I can specify the installation location: hxxp://thelinuxfaq.com/96-how-to-install-wowza-media-server-on-centos
Yes you can install more than once instance of Wowza on a physical server. You just need to ensure that interfaces, IP addresses and ports etc don't cause any conflicts. Please see this article for some pointers. It's specific for version 3, but you can use it as a base to build on if using Streaming Engine (version 4).