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BlackBerry Development Advisor
Posts: 15,727
Registered: ‎07-09-2008
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My Carrier: Bell

Re: Appworld screenshots on PlayBook have horrible pixelation issues due to JPEG over compression

Please post a link to your app or your app name if you are still seeing issues.  Thanks!

Mark Sohm
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Developer
Posts: 323
Registered: ‎05-07-2009
My Device: BlackBerry Z10, PlayBook, 9900
My Carrier: Telus

Re: Appworld screenshots on PlayBook have horrible pixelation issues due to JPEG over compression

Thanks MSohm... I think realistically you could point to any app, but here's a few examples of my own...

(note, the images appear ok in desktop browser version of appworld)

 

1st app: "5 Marbles" (zoomed in)

pixelationZoomedIn.png

 

Desktop AppWorld link: http://appworld.blackberry.com/webstore/content/85895/

 

around any of the colored marbles in the "box" they are in, you see what looks almost like soap bubbles in each of the 4 corners.. (they're JPEG compression artifacts)

 

 

2nd app: "Dots+Boxes"

pixelationZoomedIn2.png

 

Desktop AppWorld link: http://appworld.blackberry.com/webstore/content/screenshots/58927/

 

If I zoom in on these shots in Desktop Appworld they look like this:

 

desktopappworld.png

 

 

Note... all of these shots were zoomed in 300% from their delivered size (on device or desktop)... and all of them are "Shrunk" from the original screenshot size of 1024x600 to a max size of 640x640 (no uneven scaling) in order to be submitted to appworld so there is some "loss" of quality due to shrinking... however when viewed at 100% in appworld on the PlayBook, they should look very similar to appworld on the desktop (that would look like this):

 

desktopappworld100percent.png

 

where everything might be small, but the image is crisp and indicates that this app does have decent quality graphics etc.

 

 

On a related note, since many of us are uploading our screenshots in PNG forma (a lossless format which is ideal for screenshots) it would be very nice if AppWorld on the device could load a sized-as-needed PNG image (or even better, simply match the uploaded format) ;-)

 

Cheers,

Steve

 

 

 

 

 


PlayBook Apps: DataMine, Dots + Boxes, 5 Marbles
BlackBerry SmartPhone Apps: 5 Marbles Soon: **** (D.Z.A), ****Quest, **** Challenge, VaultCracker, DevBrowser, Radial****
Developer
Posts: 6,473
Registered: ‎12-08-2010
My Device: PlayBook, Z10
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Re: Appworld screenshots on PlayBook have horrible pixelation issues due to JPEG over compression

[ Edited ]

steve_web, I was just comparing my file sizes (as submitted) under a few conditions, for kicks.

 

For my portrait-mode (375x640) screenshot of Battery Guru, the PNG file is 184K.

 

A 90% quality JPG file is 45K.

 

A 70% quality JPG is 25K.

 

A 50% quality JPG is 18K.

 

The quality of the current shots seems to be somewhere just above the 50% quality mark, comparing with my own images above.  The previous ones were probably well under that, around 25% and maybe 12K.

 

I suspect there are issues with server load, bandwidth (e.g. for cellular connections with the phones), and flash storage space which need to be taken into account. They probably overshot the mark in 2.0.0 but, given how quickly the file size grows above 70% quality I don't expect we'll ever see PNG files being used directly...


Peter Hansen -- (BB10 and dev-related blog posts at http://peterhansen.ca.)
Author of White Noise and Battery Guru for BB10 and for PlayBook | Get more from your battery!
Developer
Posts: 323
Registered: ‎05-07-2009
My Device: BlackBerry Z10, PlayBook, 9900
My Carrier: Telus

Re: Appworld screenshots on PlayBook have horrible pixelation issues due to JPEG over compression

The JPEG quality is definately the item in question here...

 

I realize there are savings to be had for every "10%" reduction in the output quality... but there's a threshold where the savings are not worth it because the image quality is all but gone.

 

I ran a similar test with a full screenshot of my app: 1024x600... saved as a PNG24 image.

 

I resized it to 494x290 (the size rendered in appworld on the playbook) keeping it as PNG24

 

494x290 PNG: 272Kb

 

then saved a 100% quality JPEG (from the source PNG)

494x290 JPG: 155Kb

 

then saved a 90% quality JPEG

494x290 JPG: 117Kb

 

then saved a 80% quality JPEG

494x290 JPG: 86Kb

 

then saved a 70% quality JPEG

494x290 JPG: 65Kb

 

then saved a 60% quality JPEG

494x290 JPG: 55Kb

 

Beyond the 60% mark there were just way too many artifacts...  my testing pegs the current image compression around 40% (about 29Kb)  While I realize there is a significant bandwidth savings between 40% and 60%... I don't see it being worth it if the image quality is all gone.

 

 


PlayBook Apps: DataMine, Dots + Boxes, 5 Marbles
BlackBerry SmartPhone Apps: 5 Marbles Soon: **** (D.Z.A), ****Quest, **** Challenge, VaultCracker, DevBrowser, Radial****
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Developer
Posts: 161
Registered: ‎02-08-2012
My Device: PlayBook
My Carrier: None yet

Re: Appworld screenshots on PlayBook have horrible pixelation issues due to JPEG over compression

[ Edited ]

I see little change from 2.0.0 to 2.0.1, involving screenshots with any amount of text in them. Bandwidth is cheap, if you must, make high quality small thumbnails, and allow them to be expanded to full size at the user selection, or something. You don't see any of the other app stores out there serving up screenshots like ..

 



especially when viewing it from a PC, but also not on devices either. I've got pretty much every mobile operating system here that has an app system, and none of them do this.

The image uploaded in the app control panel is a PNG.

 

The compression artifacts aren't so mcuh visible on a PC until you zoom in, and then it could easily be blamed on zoom, but on PlayBook, it's seriously not good looking.