Script To Limit File Size On Video Share Server

We have found that we need to limit the amount of cpu uage by users on our video share server. On this server we currently have 20 users on a sharred plan. Thought that the obvious BW usage would be the biggest challenge, as it turns out we havent gone over the 2 TB that we have.

We have come up with an encoding process that uses the 264 codec and gives us excellent results in terms of quality but is very cpu intensive to the point of really slowing down the server when 10 or more users simutaneously are encoding their videos.

Can someone suggest a script that would allows us to limit the file size in terms of MB/GB that each user could upload per month.

So for example a client pays 10.00 per month and we wanted to limit their uploads to a total of 900 MB per month vs the client that is paying 50.00 per month who would have the ability to upload say 8 GB per month.

Cento 5
c-panel
Dual Quad Core 2.0 ghz
6Mb Ram
1TB HDD
2 TB of BW