Building a Standards Converter

[Cardigan]

Hi Cardigan
The input signal has to be 4:3 as it simply crops part of the beginning and end of each line to make it fit 5:4. 

Thanks for that. The reason I asked is because it seems to be something that is not being addressed at the moment - the ability to convert what has become the standard aspect ratio for broadcasting into what older television sets require. I suppose that as the most likely feed is a set top box, that can easily be set to give a 4:3 output anyway so the point is moot. It also saves you having to do line-rate interpolation to get 4:3 from the 16:9 input at the same time as you are carrying out interpolation to get the 405 signal.

Yours has a valuable first - 5:4, which is commendable.