Attila Kinali wrote:
On Tue, 17 Jul 2007 11:37:08 -0700 James Richard Tyrer
<[EMAIL PROTECTED]> wrote:
This chip appears to be able to do color space conversion and
scaling for 1080p line picture.
http://www.i-chipstech.com/pdf/C762%20Brochure.PDF
The features are nice, but nothing we really need. I think the chip
is intended for full 1080i/p HD-TV producers that are not capable or
do not have the time to build their own scaler/deinterlacer.
Main problem with this chip will be its interface (it doesn't
integreate well into OGAs current layout) and the lack of YUV 4:2:0
support (most common subsampling format)
The scaler isn't necessary for us as OGA will have one anyways (for
the 3D stuff).
I thought that the hardware scaler would only be used for video.
The color space YUV->RGB conversion is rather simple to implement.
Yes, simple to implement, but computationally expensive, and therefore,
costly to implement -- large amount of chip real estate needed.
Upsampling from 4:2:2 to 4:4:4 is nothing difficult either (simple
FIR filter operating on scanlines), but the upsampling from 4:2:0 to
4:2:2 is (upsampling in vertical direction, guess why they don't do
it).
Perhaps it is because it isn't needed. Which decoders output 4:2:0?
Deinterlacing is something that cannot be really done without
some information from video source (or some assumptions on the video
output device) and if only a simple implementation is used (which i
assume), then the quality will suck.
Are we talking about motion compensating deinterlacing (for sources
originally shot with an interlaced video camera and recorded on tape)?
or just cine deinterlacing where all that is needed is to rearrange the
fields from 3:2 pull down so that you always display an odd and an even
field from the same film frame together?
All in all i would say we are better off to implement the stuff done
by this chip in OGA directly.
It is always better to implement stuff directly, unless it costs more to
reinvent the wheel.
--
JRT
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