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CwF

Member

Registered: 2018-01-28

Posts: 305

Thunar's image preview with Videos

I've come across an interesting feature of thunar's image preview side pane. It is not intended for video as far as I know, but accidentally I noticed it gave a preview of a mkv file that was missing its extension, just the name. The type is identified correctly as ‘Matroska stream’ and acts the same with the missing extension. If I add the extension, then thunar doesn't give a ‘image preview’. What is going on!? I tried removing the extension from an mpg, no deal. For my own creation I call .dv (MPEG-4 Video), remove that extension and it also gives a preview!

Detailed flow, recorded broadcast tv .mpg > avidemux stream copy edited to .mkv or m4v > handbrake to h265 .dv

tumbler is installed and not fully enabled if it's related.

It seems the extension filters the file from being processed for the image preview. Is there a fix for this to allow the extensions?
Or maybe I'm in between versions and video previews are coming!

I noticed this on Debian 12.7 with thunar 4.18.4

ToZ

Administrator

From: Canada

Registered: 2011-06-02

Posts: 11,482

Re: Thunar's image preview with Videos

It looks like it uses the same thumbnailing processes to display the images. Do you see thumbnails for the videos that don't display?

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CwF

Member

Registered: 2018-01-28

Posts: 305

Re: Thunar's image preview with Videos

No, I don't have any extra thumbnailer plugins at all and set for local files only or never. The extensionless files do show a thumbnail in thunar as if ffmeg thumnailing is active when it is not installed with 'local files'. All the other files have generic icons. I know the thumbnails would show if the extra plugins were installed, but this oddity suggest there is another path working and yet inhibited.

Setting for display never in thunar does block the thumbnails from being displayed. However the Side pane is still capable of showing the preview without external help, but will not for the same file with the extension added.

The odd behavior does not work with image files, they display normally as expected in the side pane. For the video files with extensions, manually selecting image preview from the menu works for a one-off view, but not automagically on selection, like the extensionless files do.

Understand, nothing broken, just a happy good bug for a change, and nothing to ‘fix’. I'm used to not using thumbnails beyond the generic distinctions.  I assume a priority issue among thumbnailers is the cause? Some default ffmpeg capability is there but is masked by the lack of the plugin? There is a noticeable delay to displaying this image preview so it does seem to be on demand per demand and not pre-cached in parallel. Moving highlight to another file and back give the same delay each time, so whatever process is called each time without caching. So using the plugin is likely more responsive for those that want it. Now that I think about it, it seems to correct to mask it if there is a delay to slow down thunars responsiveness, and insist on the menu click to display it. It interesting the lack of an extension exposes this.