Xpra: Ticket #2642: No matching CSC module found

Log output is too massive, attaching it.

No idea what caused it, since it didn't cause any disruption (apart from the looming #2617).

This would be my most massive usage of xpra client to-date;

                                        Xpra top 3.0.7-r25609
Xpra GTK3 X11 server 64-bit
xpra top - 16:32:13 up 1 day, 6:42:46,  1 users, load average: 1.52, 2.19, 2.12
8 threads
cursor at 2030x358
 ┌──────────────────────────────────────────────────────────────────────────────────────────────────┐
 │Python/GTK3 client version 4.0-r25603                                                             │
 │batch delay: 994 (909)                                                                            │
 │latency: 0 (0)                                                                                    │
 └──────────────────────────────────────────────────────────────────────────────────────────────────┘
5 windows
 ┌──────────────────────────────────────────────────────────────────────────────────────────────────┐
 │quartz@h: ~                                                                                       │
 │1920x1002 at 1600,23 - gravity=1, base-size=(12, 50), minimum-size=(298, 79), increment=(9, 17)   │
 │focused, maximized                                                                                │
 │NORMAL                                                                                            │
 └──────────────────────────────────────────────────────────────────────────────────────────────────┘
 ┌──────────────────────────────────────────────────────────────────────────────────────────────────┐
 │Terminal                                                                                          │
 │166x158 at 1601,79                                                                                │
 │grabbed, override-redirect                                                                        │
 │POPUP_MENU                                                                                        │
 └──────────────────────────────────────────────────────────────────────────────────────────────────┘
 ┌──────────────────────────────────────────────────────────────────────────────────────────────────┐
 │2020-Mar.xlsx - LibreOffice Calc                                                                  │
 │1920x1017 at 1600,23 - gravity=10, base-size=(0, 0), minimum-size=(136, 39)                       │
 │maximized                                                                                         │
 │NORMAL                                                                                            │
 └──────────────────────────────────────────────────────────────────────────────────────────────────┘
 ┌──────────────────────────────────────────────────────────────────────────────────────────────────┐
 │atf â   qwertyuiop[asdfghjkl;cvbnmk,l;fghjkl                                                      │
 │1920x1017 at 1600,23 - gravity=1, minimum-size=(324, 39), position=(2141, 74)                     │
 │hidden, iconic                                                                                    │
 │NORMAL                                                                                            │
 └──────────────────────────────────────────────────────────────────────────────────────────────────┘
 ┌──────────────────────────────────────────────────────────────────────────────────────────────────┐
 │LibreOffice 6.4                                                                                   │
 │1x1 at -99,-99                                                                                    │
 │override-redirect                                                                                 │
 │NORMAL                                                                                            │
 └──────────────────────────────────────────────────────────────────────────────────────────────────┘


Fri, 13 Mar 2020 14:37:52 GMT - stdedos: attachment set


Fri, 13 Mar 2020 15:02:26 GMT - Antoine Martin: status changed

Weird, we're using video for a 2x16 area:

Error: no matching CSC module found
 for 2x16 GBRP source format,
 to 2x16 BGRA or BGRX or RGBA or RGBX or BGR or RGB

Sat, 14 Mar 2020 12:22:17 GMT - Antoine Martin: owner, status changed

That's very strange, we already had code that prevents using video regions for small areas:

        if cww*cwh<=MAX_NONVIDEO_PIXELS:
            return nonvideo(quality+30, "window is too small")

And the default value:

MAX_NONVIDEO_PIXELS = envint("XPRA_MAX_NONVIDEO_PIXELS", 1024*4)

So it should not have been possible to use a video encoding for 2x16, unless you somehow forced it with command line options or environment variables?

r25632 will ensure we never bother using video for anything smaller than 16 pixels in width or height, since not all CSC modules can handle very small sizes. The correct fix would be to add a new capability so the client can tell the server what the minimum size requirements really are, but since all the CSC modules we have support at least 8, I didn't bother.

It would be interesting to see why we ended up choosing video for such add odd looking window region.

Do you know which window triggered it? (r25633 will show the window id in the exception message from now on)


Sat, 14 Mar 2020 18:22:07 GMT - stdedos:

(..) So it should not have been possible to use a video encoding for 2x16, unless you somehow forced it with command line options or environment variables?

I am trying to keep my changes in the console and in one configuration file, and as minimal as possible. I am inclining to say no (the changes required here are already complex enough to inadvertently apply them).

(..) Do you know which window triggered it? (r25633 will show the window id in the exception message from now on)

No, unless things "complain violently", a lot of things go on auto-pilot. I will have at least one more big session coming up, and I think client betas are already out. Fingers crossed.


Thu, 19 Mar 2020 16:20:28 GMT - Antoine Martin: milestone changed


Fri, 20 Mar 2020 10:07:03 GMT - stdedos:

I cannot re-trigger it.

No client or server log is found to contain 'no csc module found' 😕

Found it (see attachment, the spam is SO MUCH)


Mon, 23 Mar 2020 15:45:26 GMT - stdedos: attachment set


Fri, 27 Mar 2020 12:27:27 GMT - stdedos: attachment set


Wed, 01 Apr 2020 13:20:58 GMT - stdedos: owner changed

If you are using JetBrains products (Find Action/File/Symbol, toast notifications, hovers e.g. commit message from Annotations) or Sublime Merge, you'll definitely hit this one.

Maybe this is somewhat helpful. From RubyMine:

2020-04-02 10:55:39,180 [   8465]   WARN - openapi.wm.impl.ToolWindowImpl - ToolWindow icons should be 13x13. Please fix ToolWindow (ID:  Problems View) or icon jar:file:~/.local/share/JetBrains/Toolbox/apps/RubyMine/ch-0/201.6251.5/lib/icons.jar!/general/warning.svg

Thu, 23 Apr 2020 09:48:44 GMT - Antoine Martin:

ToolWindow icons should be 13x13

This could be because MS Windows simply cannot create very small non-OR windows. If that's the case, then it won't occur with macos or Linux clients.

This may cause problems with some applications.


Thu, 28 May 2020 05:01:35 GMT - Antoine Martin: owner, status changed

Also reported elsewhere: #2780


Sat, 23 Jan 2021 05:56:51 GMT - migration script:

this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/2642