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Well it doesn't sound like the Altera VIP is suitable for your needs. For someone of your experience level I expect that you've already got a scaler written that you've used in other products. Is there a reason why not to use that scaler here? If it's a matter of wrapping the avalon logic around it that's pretty straitforward.
I will make mention of something for others. The algorithm mentioned by Tricky is typically referred to as nearest-neighbor without filtering. The Altera Chroma Resampler does support a simple luma-adaptive upconversion which basically applies a simple sinc() filter.
In addition to the additional logic required for the filtering one should always bare in mind that the Altera VIP functions also require logic for the video control packet removal and insertion. So there is additional logic beyond that needed for the video processing.
Jake
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Jake,
To answer your question. Yes, and yes, and, by the way, yes again! We
always end up developing our own custom functions
after spending valuable man-weeks of time attempting to use Altera's IP based upon
their descriptions of use. (BTW, I am not the only one who is frustrated here...read the other posts...)
The
entire reason why we would purchase someone else's IP is to
save time! That is the only reason why anyone would purchase HDL IP. You trade time for money. You have obviously missed this point, or tend to develop in a vacuum and without deadlines.
The VIP Suite may be great for university students who are learning how to use Altera's tools and are trying to fulfill their credit requirements, but I question the validity of it's use for a purpose such as ours. Our intention was to use the VIP suite to aid us in fast and reliable feasibility studies. We never intended to use the IP as part of product, only to aid us with idea development.
We also recognize that there are always learning curves for any such new IP. However, when one cannot rely on the documentation or paid subscription support, it becomes an issue regarding the value received with respect to money paid.
I also understand that Altera is in the business of selling chips. The software tools and IP are secondary from a corporate viewpoint. That too, is a no-brainer. However, we are not in this boat either. We perform pure research and use Altera's tools as a vehicle to get to where we want to go, and nothing more. Hence, the lack of dedicated support from Altera.
Regarding the issue of creating wrappers for our own components for insertion into the Avalon fabric: we have done this as well - back with v7.1 when it was easy...however, attempting to reuse any of these components now in v9.1 is impossible.
The avalon interface specifications change with each new version of Quartus. This is quite frustrating and time-consuming as well. What this means to us is a complete re-write of the interface to match the new specification. Specifically, with the advent of the Video-ST interface found in all of the Video IP Suite components, there is no longer direct correlation between legacy Avalon interconnect specifications and the new streaming video interconnect specifications.
Time is money, and changing our components interfaces to match the new specification requires time to research the new spec, time to think about the changes, and time to implement the changes and debug. This is self-defeating. It would have been easier to be able to read documentation, understand documentation, make rational decisions based upon clear documentation, and then decide to implement paid IP or develop custom components.
rick-
Honored Contributor
