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Visitor
Visitor
3,459 Views
Registered: ‎07-24-2016

Is there degradation in quality with video scaler scaling factor > 0.5?

Hi,

 

Is there degradation in quality with Xilinx video scaler,scaling factor > 0.5?

We want to convert from 2592*1944 to 1440*1080. Scaling factor , Horizontal SF =  0.5559 (2592/1440) , Vertical SF = 1080 / 1944 = 0.5555.

 

We are observing some degradation in quality of output image . Also sharpness is missing in the image . 

If we reduce the scaling factor to 'less than or equal to' 0.5 , will there be any improvement in quality ?

 

[To reduce the scaling factor either we need to increase input resolution(not possible in our case) or need to decrease the output resolution]

 

 

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Xilinx Employee
Xilinx Employee
3,456 Views
Registered: ‎08-01-2008

Re: Is there degradation in quality with video scaler scaling factor > 0.5?

it should not be
share input and output image
which version of IP you are using
Thanks and Regards
Balkrishan
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Visitor
Visitor
3,446 Views
Registered: ‎07-24-2016

Re: Is there degradation in quality with video scaler scaling factor > 0.5?

Thanks for the reply.

 

The version of scaler IP I am using is 8.1.

 

I can share the output image . But , first thing i need to know is , 

What is the dependency of scaling factor on quality of image ?

Which scaling factor is better ? >0.5 or <0.5 or = 0.5.

 

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Scholar
Scholar
3,427 Views
Registered: ‎04-26-2015

Re: Is there degradation in quality with video scaler scaling factor > 0.5?

Your output image has about 70% fewer pixels than your input image, so obviously you'll be losing a lot of fine detail. Larger scaling factors (closer to 1) mean that there's more information available in the output image, so less information has to be thrown away.

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Visitor
Visitor
3,340 Views
Registered: ‎07-24-2016

Re: Is there degradation in quality with video scaler scaling factor > 0.5?

Thanks for the reply.

 

According to you larger scaling factors only give better result :

Say , For input resolution 2592*1944 , 

Output resolution 1920 * 1080 (HSF = 0.74 , VSF = 0.555 ) gives better result than 1440 * 1080 (HSF = 0.555 , VSF = 0.555) and 1280*720 (HSF = 0.4938 , VSF = 0.666)  , right ?

 

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