[opendtv] Re: Video compression artifacts and MPEG noise reduction
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Wed, 18 Jun 2008 10:25:09 -0400
Tom Barry wrote:
> Personally I think most of the clever noise reduction algorithms
> just end up removing high frequency detail. And once that is done
> it would be a better bit savings to just resize and compress the
> picture to a lower resolution.
What makes this particular product interesting is that they filter the
static parts of the image and the moving parts separately. So, for
example, tuning out mosquito noise and reducing macroblocking in
fast-moving scenes are two separate filter settings. So you can reduce
macroblocking, which will cause some loss of detail of the fast-moving
objects, but at the same time, not affect the sharpness of the rest of
the image.
In spite of Craig's continued protestations, it looks like this is used
exactly as they claim, and exactly as I first thought. It is used by the
broadcast station to process its compressed individual multicast streams
before they are combined in the multiplex. The VNR-1000-HD, or its SD
cousin, can take in either compressed or uncompressed digital inputs.
Suggest reading the manual, especially the last half of it, where they
give suggestions for how much filtering to dial in.
http://www.algolith.com/fileadmin/user_upload/broadcast/3031-8001UG-200.
pdf
Bert
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