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Author Topic: Request: Image Scaling Quality Improvements  (Read 3796 times)

Headcool

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Request: Image Scaling Quality Improvements
« on: February 22, 2015, 11:45:01 pm »

Currently, series- and movie-images are quite blurry, if the are scaled down to a size of under ~400x600px.
Example
Original Example Image

Scaled down with JRiver


Scaled down with paint.net


It can easily be seen, that the quality of the example image scaled down with paint.net is much better than that of the one scaled down with JRiver.
Since appearence is one of the most important aspects of a multi media application like JRiver, the algorithm used for image scaling should definitely be improved.
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6233638

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Re: Request: Image Scaling Quality Improvements
« Reply #1 on: February 23, 2015, 07:50:04 am »

I have been complaining about this for a long time. It's not limited to series/movie images. Everything is horribly low quality.
 
Media Center:

 
Photoshop:
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Matt

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Re: Request: Image Scaling Quality Improvements
« Reply #2 on: February 23, 2015, 09:09:17 am »

The scaled down image will be a thumbnail until the size gets big enough.

But once the size is big enough, it's a scaled down full resolution image using bicubic sizing (the highest quality available).

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Matt Ashland, JRiver Media Center

Arindelle

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Re: Request: Image Scaling Quality Improvements
« Reply #3 on: February 23, 2015, 09:18:52 am »

Quote
Since appearence is one of the most important aspects of a multi media application like JRiver,
one the the most important?

I've found just using cover art of 1000x1000px or above cures almost any monitor issues personally. For retina ipads and really high resolution a little more maybe ...
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6233638

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Re: Request: Image Scaling Quality Improvements
« Reply #4 on: February 23, 2015, 09:39:14 am »

The scaled down image will be a thumbnail until the size gets big enough.
But once the size is big enough, it's a scaled down full resolution image using bicubic sizing (the highest quality available).
Images should always be scaled down, never scaled up.
And the thumbnail quality is far too low.
Browsing my library looks like a web image gallery from the mid-90s.
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Hendrik

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Re: Request: Image Scaling Quality Improvements
« Reply #5 on: February 23, 2015, 11:14:10 am »

Checking on some improvements to image scaling has been on my list, since Matt noticed a problem with our bicubic scaler some time ago as well and asked me to look into it. But its a complex topic, so it won't happen over night.
One problem is that cubic doesn't behave well when using strong downscales (< factor 0.5), and a box averager might be preferable.
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~ nevcairiel
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6233638

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Re: Request: Image Scaling Quality Improvements
« Reply #6 on: February 23, 2015, 12:51:58 pm »

One thing that would really improve the quality of downscaling to thumbnail-sized images would be to use linear-light scaling, but I don't know if you'd consider that to be too computationally expensive.
But the biggest issue is that there is so much JPEG compression. (particularly the chroma quality)
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Headcool

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Re: Request: Image Scaling Quality Improvements
« Reply #7 on: July 05, 2016, 11:46:51 am »

-Fix Cover Art Scaling
Cover Arts/Thumbnails look really blury, except when they are taking up a large portion of the screen - which they normally don't because I want to have at least 4 columns.
In my point of view this is a major drawback. MC has a reputation of high quality DSP, audio- & video-playback, but the GUI looks worse than that of the any competitive product including the free ones.
I do understand that the perception of the GUI is subjective, but I don't think anyone wants to have a blury one. And people that want to have high quality playback also want to have a high quality GUI.

I think a fast solution would be to allow the user to configure at which displayed size of a cover art, the orginal- and at which a thumbnail is downscaled.

A longterm solution I have already posted in this thread would be to use OpenGL/Vulcan/Direct3d to render cover views. This way you can just put the original cover art images that are currently displayed (+ the ones above and below for better scrolling) into the GPU memory. The 3D API will do the rest - mipmapping, scaling, AF, etc. If done that way, no matter how fast I scroll, how big or small the displayed cover art is, it will always be sharp from the first frame it is displayed on.
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