A recent playback quality and colour bug on Windows was reported by a user on Chromium Gerrit. The OP observed aliasing and colour issues in the video.
He said that when the video was played at a low resolution, like 144p and it was not occluded, aliasing/pixelation was observed.
But, surprisingly, the effect vanished when the mouse hovered over the screen. A similar sort of issue affected colors. In the lighter colour sections of the video, when the mouse was moved over the screen or the screen was scrolled down, the colour of the video changed.
What was reported, is discussed below.
How to reproduce the problem
This section deals with the problem in the quality and colour of the video and the changes that occurred in the quality and colour of the playback when the mouse was moved over the video.
- Navigate to sample video https://www.youtube.com/watch?v=w4wvgbnzhlA&list=RDded49w9Fr4k&index=3
- Set the quality to 144p.
- Make sure the video is not occluded. E.g. the mouse is not hovering over the video and the page is not scrolled down at all.
- Observe pixelation/aliasing on the video.
- Move the mouse over the video.
- Observe the aliasing goes away.
- Navigate to sample video https://vimeo.com/302312473
- Skip to a section of the video that is lighter in color, e.g. 1:24.
- Observe the colour of the video.
- Mouse over or scroll down on the page to partially cover the video.
- Observe the colour changes on the video.
This was a strange thing observed. It was expected that the video should not be pixelated when not occluded and the video colour should not change when it was not occluded.
But the results were opposite to the anticipations and the video quality was dramatically worse when the mouse was not over the video. Whether this problem was with Flash or HTML5? It was with HTML5.
This issue was observed in:
- Chrome version: 72.0.3626.119 Channel: stable
- OS Version: 10.0
- Flash Version: 18.104.22.168
Reportedly, this issue of video upscaling can be solved by calling SetBitmapInterpolationMode() to change the interpolation mode to linear.
Improve the video upscaling quality in low-resolution mode on Windows This is done by setting interpolation mode to linear indirect composition visual. The visual default is the nearest mode and the quality is not good. The upscaling quality improves after calling SetBitmapInterpolationMode() to change the interpolation mode to linear.
It is reported that this bug has been fixed in the stable release of Chrome. But one user reports that he still observes this issue.
I am still seeing the behaviour on the stable release of Chrome. Has the finch change taken effect on the stable branch yet?
The upcoming Chrome update will reportedly fix this issue for good.
Do you face a similar issue? Why not let us know in the comments below?
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