If you go to the test site here
https://qa.moodle.net/?lang=ar
The lang=ar
means language=arabic, or at least I think it does but the principle is correct. You will still see a whole bunch of English that has been added as content. You can create a free MoodleCloud account set the language to Arabic and experiment with that to ensure everything will appear in your language of choice.
As for an estimated cost, you are going to have to spend some time defining exactly what you want. Much of it will not be Moodle work, because as others have commented Video stuff should be done with specialist video tools. If you are going to have large numbers of users I suspect Catalyst have the most experience in that area (I have no commercial connection with them)