View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000169 | madVR | bug | public | 2014-03-01 18:23 | 2014-03-04 00:29 |
| Reporter | bacondither | Assigned To | madshi | ||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | closed | Resolution | fixed | ||
| Summary | 0000169: Dithering of reference white with error diffusion | ||||
| Description | On all white images(RGB 255) and video (RGB 235 reference white) after dithering with error diffusion 1 or 2 in 8-bit mode, the outputted image consists of RGB 254 and RGB 255 pixels. It should only consist of RBG 255 pixels. Using random dither or no dither gives only RGB 255 white pixels which is correct. | ||||
| Steps To Reproduce | Load an all white image or try the AVS 3-White Clipping.mp4 test pattern with ED 1 or 2 enabled. Then use a image editor to clip the lower part of the histogram >250 to se the dithering of whites more clearly. | ||||
| Tags | No tags attached. | ||||
| madVR Version | madVRfinalDither4 | ||||
| Media Player (with version info) | MPC-HC 1.6.8 and 1.7.3 | ||||
| Splitter (with version info) | LAV Filters 0.60.1 | ||||
| Decoder (with version info) | LAV Filters 0.60.1 | ||||
| Decoding | Software | ||||
| Deinterlacing | none (progressive) | ||||
| DXVA2 Scaling Active | no | ||||
| Aero / Desktop Composition | On | ||||
| Problem occurs with mode | all modes | ||||
| GPU Manufacturer | AMD | ||||
| GPU Model | 7790 | ||||
| GPU Driver Version | Radeon HD 7790 Catalyst Performance Driver 12.101.2.1 and 14.2 Beta | ||||
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Was able to reproduce this on both Intel and AMD GPUs. Not sure why this happens. It seems that the interop between D3D9 and DirectCompute somehow slightly effects the pixel range. I've now applied a manual correction, which seems to take care of the problem with Intel GPUs with both TV and PC output levels. It also fixes the problem with AMD GPUs with TV output levels. But AMD GPUs with PC output levels still have a dither pattern of 254-255. If I increase the correction for this, it would push white too high for Intel. So I think I'll keep it this way. AMD users either have to live with this, or alternatively run a custom pixel shader which slightly expands the video (e.g. using a simple multiplication factor of "255.2 / 255.0"). |
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P.S: Found a proper fix that seems to work for all GPUs and all situations. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2014-03-01 18:23 | bacondither | New Issue | |
| 2014-03-01 18:23 | bacondither | File Added: noise whites.zip | |
| 2014-03-01 20:10 | bacondither | Media Player (with version info) | MPC-HC 1.6.8 => MPC-HC 1.6.8 and 1.7.3 |
| 2014-03-01 20:10 | bacondither | GPU Driver Version | Radeon HD 7790 Catalyst Performance Driver 12.101.2.1 => Radeon HD 7790 Catalyst Performance Driver 12.101.2.1 and 14.2 Beta |
| 2014-03-01 23:10 | madshi | Assigned To | => madshi |
| 2014-03-01 23:10 | madshi | Status | new => assigned |
| 2014-03-02 15:01 | madshi | Note Added: 0000401 | |
| 2014-03-02 15:01 | madshi | Status | assigned => closed |
| 2014-03-02 15:01 | madshi | Resolution | open => fixed |
| 2014-03-03 12:44 | madshi | Note Added: 0000404 |
