wow!
All these details !?
Well, please allow me to tell you more exact details so I can get an exact device instead of confusing you with my broad question.
We are a small media company located at Egypt, Cairo.
We have two departments in our company, one for web development and the other one is for media encoding.
We have many contracts with many local channels here in Egypt which broadcasting in the Nilesat Satellite.
Our contracts include two aspects:
1) Developing a website for any channel we have a contract with.
2) Uploading all channel shows or programs to its website on a daily base.
* some contracts include extra section for adding these videos to the social networks like YouTube, Facebook, twitter ...etc in the channel owned page or account or channel.
3) At the beginning when we started we used to receive an original DVD copy of the broadcasted episodes then do video encoding and upload to the website, but this became a time consuming by time because we are waiting for the second day to receive the copies then do the video encoding then do the upload in the 3rd day which became a time consuming by time and lead to lose some contracts.
4) Now we do it in a better way, we have a lab with 50 computers connected with a gigabit network and each computer include a PCI DVB card and only dedicated for recording, then we do transfer the .MPEG-2 recorded files to other monster computers with i7 processors to do the video encoding and then upload then ...etc. The reason for do it is to save a day and a half by recording locally and directly from the channel.
5) This was the starting point of our problems and the main reason for my search about Dimensions and Aspect Ratios.
6) Here in Egypt we have the default normal channels and only about 10 or so are in HD so channels we have contracts with is broadcasting using various Dimensions and Aspect Ratios like : 720x576 & 704x576 & some other Dimensions.
7) The local channels used to add some commercials in the bottom of the screen and some commercials in between the episodes (which was not existing in the original DVD we receive from the channel previously as we used to get the net pure episode).
8) so now we do it our self to remove all these because all uploaded previously were pure and audience will not like it this way.
9) so now when do a crop I get a mess ... so this is the reason I asked my 1st question about Dimensions and Aspect Ratios.
10) Now we are need to upload various Dimensions like 640x480 and others.
11) what I do so far like the following:
- - use MPG2CUT2 to determine required parts.
- do crop.
- When we do the 640x480 when the channel is 720x576 and I do crop for 10% from the bottom, so the new size is 640x432 to have a pure acceptable size.
But if the channel is not that size I do not know how to adjust it?
And to make a more small size like 480 or 360 or 352 I do not know what are the Dimensions and Aspect Ratio?
So please advise.
Thanks and really very sorry for being chatty but just to let you know more exact details to better help me.
Thanks for your time 
