#245 closed defect (wontfix)
0.8.1: text flickery with x264 and min-quality<70
Reported by: | onlyjob | Owned by: | Antoine Martin |
---|---|---|---|
Priority: | major | Milestone: | 0.8 |
Component: | core | Version: | trunk |
Keywords: | Cc: |
Description
With 0.8.0 and 0.8.1 I experience text "flickery" (visual distortion) in kate
with "x264" encoding and min-quality < 70.
With several paragraphs of text in kate
all text is flashing in the rhythm of cursor flashing. Setting min-quality to 70 is enough to fix the problem.
Change History (4)
comment:1 Changed 9 years ago by
Owner: | set to Antoine Martin |
---|---|
Status: | new → accepted |
comment:2 Changed 9 years ago by
Just tested and I managed to reproduce the flickering issue in Kate. That's because the Kate application re-paints the whole line (or more?) every time the cursor blinks - so xpra does a full window refresh using x264. Then
shortly after the auto-refresh kicks in and does a lossless refresh at
high quality.
The flickering is due to the difference in quality between regular
frames and almost-lossless frames.
I'm trying to find out why the quality isn't higher on "auto" when Kate
is idle (just the cursor blinking), "xpra info" reports a quality of about ~80% when it looks like it should go much higher (and therefore avoid all flickering by virtue of already being lossless).
PS: The problem manifests even more wildly if kate has spellchecking enabled and some words are underlined.
comment:3 Changed 9 years ago by
Resolution: | → wontfix |
---|---|
Status: | accepted → closed |
I don't think there is much we can do about this at all, when using YUV422
or YUV420
, the colour subsampling will do this - the only way to avoid it is to not use it: setting a quality high enough so that YUV444
is used (by default the threshold is at 90%).
The quality
and min-quality
options can be set:
- via
/etc/xpra/xpra.conf
- via
~/.xpra/xpra.conf
- via the command line
- via the applet
comment:4 Changed 16 months ago by
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/245
70 is the minimum quality level for YUV422, below that you would be using YUV420 colour subsampling.
What is strange is that you get a full window refresh with just a cursor change. I guess that kate is updating the whole line or something, so we end up with a full window refresh rather than a small lossless (png/rgb24) region. Will test.