BUG: AfterShot Pro 2 and Pentax K-50 DNG RAW Files

[clem]

Using AfterShot Pro 2 (ASP2) as usual. Enabled OpenCL Acceleration to speed up rendering of Pentax K-50 DNG RAW files under Ubuntu Linux (14.04, Trusty Tahir). Images were taken in the horizontal, or traditional 'landscape' camera orientation. Artefacts began to appear both on-screen and in the TIFF and JPEG files rendered by ASP2. These strange horizontal lines and spots affected nearly all of my images taken with the K-50, and occur at and between Y-coordinates 2559 to 2564, inclusive. Some span the entire photograph, other times the lines are visible but boken up, or just fuzzy splotches appear. They become quite apparent at 200% zoom. They also appear in the DNG RAW files provided by another K-50 user, proving it is not exclusive to my copy of the camera. Disabling OpenCL acceleration in the ASP2 preferences menu seems to solve the problem entirely. I surmise it is a bug with OpenCL acceleration.
Please view this sample raw under ASP2: http://216.18.212.226/PRODS/pentax-k50/ ... 100NR0.DNG (file may be too large to upload). On my system aretfacting is extremely prominent at 200% (see at 400% where the kind of aretefacts actually becomes clearer) at about coordinates X=[2792, 2957] and about Y=2564 (at the letters of the word VINEGAR on the bottle). This is just one example, but there are many more. The problems all but disappears when OpenCL is switched off.
This is not pixel peeping, as the artefacts can be apparent at much lower magnifications.

System specs: AMD A10 CPU, 8 GB RAM, AMD Radeon HD 8570 discrete graphics, Ubuntu 14.04 Linux operating system, AfterShotPro 2 (ver. 2.0.3.25)

[clem]

I should add using AfterShot Pro 2 X64 on top of Ubuntu 14.04 Linux x86_64 (all 64-bits stuff)

[Trucks]

Hi,

open it here under Xubuntu 14.04 it seems ok.

Nvidia 331.38. OpenCL Standard.

Screenshot from Geequie 16 Bit TIFF; Same ASP;

Regards

Trucks

[clem]

I wonder if the issue is specific to my video card, Unity, or maybe both...

[clem]

Just booted Windows 7 (64-bits) on the exact same machine, downloaded the drivers for my AMD Radeon HD 8570 (2GB discrete), then installed the Windows X64 version of ASP2: Same problem! It looks 99.5% certain that the problem affects this specific graphics card and OpenCL. Maybe Corel can look into this? Would be nice to take advantage of all the features ASP has to offer.

NOTE: I've just confirmed that, on my machine, this bug also affects the unpatched version (2.0.0.133) of AfterShot Pro 2 32-bits running on Windows 7 x86_64. I'll assume the same holds true for Linux on the same system and stop testing now.