How to play a video directly in a Task?

This one is a follow up to #2259
I did some tests here. Player appears, but with error message “Video format not supported”.

My mistake or KANBOARD problem?

It’s you, or your environment. No problem here, so far.

My env: Firefox 101.0 (64-bit) on Linux


My result in installation of unofficial (by wg9s) De SeaMonkey 2.53.12 beta 1 pre Mozilla/5.0 (NT 6.1; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0 Build 20220413141527 (Newly created User Profile Default Classic Theme) on German WIN10 64bit:

Does not play

My result in Chromium Version 97.0.4692.71 (Offizieller Build) (64-Bit):

Does not play

My result in FF 103.0a1 (2022-06-04) (64-Bit):

Does not play

WIN Problem? PC-Problem?

When I load the Task Page my FF Browser Console shows:

Das angegebene “type”-Attribut “video/mov” wird nicht unterstützt. Das Laden der Medienressource Anmelden ist fehlgeschlagen.
Das angegebene “type”-Attribut “video/avi” wird nicht unterstützt. Das Laden der Medienressource Anmelden ist fehlgeschlagen.
Alle Kandidaten für die Ressource konnten nicht geladen werden. Medien-Laden pausiert. 2
Source-Map-Fehler: Error: JSON.parse: unexpected character at line 1 column 1 of the JSON data
Source-Map-Adresse: dist/

Medien konnte nicht abgespielt werden. Keine Dekoder für angefragte Formate: video/mov, video/avi

My SM Error console shows:

Any Ideas?

I’ve omitted the type attribute, but renamed the file to an .avi extension.

<video width="320" height="240" controls>
  <source src="/qt.avi" >
  Your browser does not support the video tag.

Ah, you tried on your own KANBAN board?

I will try with new code later.

Yes, what else. I couldn’t see/modify your code.

Means what? How did you do?

The downloaded file from your server was simply named qt. I renamed it to qt.avi. I have no other .avi file at hand.

I tried:

  1. Visit Task #35 in FF Browser, logged in as user InterestedViewer
  2. Download 220530_5706c_KuehlgeraetAnzeige_SZLSFWDZH_AVI.avi from Attachment list
    » Became saved in Downloads folder as “220530_5706c_KuehlgeraetAnzeige_SZLSFWDZH_AVI.avi”.

That seems to differ from your observations?

The easiest way to find out what’s happening here would be that we do our tests in the same server environment. I can grant user access to my project if you request by email via Task #34, so that I can send User Data to you. Or you grant access to your project for me via email or jabber from

Now I could fully reproduce your issue with the avi file, ending up with the same result as you.

  • Firefox cannot play avi files, maybe due to a missing codec.
  • After downloading the avi-file, it can be viewed with local video player.

Personally, I find this issue not that bad. The avi format is an ancient spec from Microsoft. Nowadays, it has only a minor role.

I’d like to keep our conversation in this forum, so that others can profit from any elaborated solution.
As a Kanboard user and admin with some experience, I’m reading along here. Whenever I find something interesting, I’ll enjoy answering and help to find a solution. That’s all.

PS: I’m lurking around in channel #kanboard on IRC/ Please don’t hesitate to meet me there.

Me too.

Yes, of course. The suggestion concerning common test environment does not mean that results should not be published here in the

And Yes, none of my Browsers (SM, FF, Chromium) can play .avi

I prefer that format because of it’s reduced size: 5 times smaller without disadvantage formy applications. And so User will have to download it from my Kanboards. Or I store the video a other storage in the cloud. And link it in my Kanboards.

But seeing a preview picture and being able to play it in the task or comment also has some advantage. But playing in Comment still does not work for me at

<video width="320" height="240" controls>

I’ve joined this discussion just to cover my curiosity. Personally, I don’t see any use case for storing videos (or links to videos) in my Kanboard.

But of course, I see your point with the file size. The required extra step, to first download the avi file, would be very annoying for me. Usability first!

This is clearly a syntax error. It should be:

<video width="320" height="240" controls>
<source src="" >