Bug 485572

Summary:	Video thumbnails using ffmpegthumbs stopped working within gocryptfs mounts after updating to KDE frameworks 6.1
Product:	[Applications] dolphin	Reporter:	SC <kde>
Component:	general	Assignee:	Dolphin Bug Assignee <dolphin-bugs-null>
Status:	REPORTED ---
Severity:	normal	CC:	ax.saintclair, ipha00, kfm-devel, techsav, todorst
Priority:	NOR
Version First Reported In:	24.02.2
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description SC 2024-04-15 02:31:37 UTC

* This is a repost of https://gitlab.archlinux.org/archlinux/packaging/packages/ffmpegthumbs/-/issues/1, per packager request.

SUMMARY

Previously with `ffmpegthumbs` installed, I was able to see thumbnails for all supported video files on my various disks in Dolphin. However, after I did a system update today which updated all KDE frameworks related packages to 6.1, I noticed that the videos within my plasma vault (which is backed by gocryptfs) are no longer showing thumbnails. Video files on other filesystems are not affected.

Things I've tried:

- Reboot. No change in behaviour.
- Reinstalling `ffmpegthumbs`. No change in behaviour.
- Create a symlink on a "regular" file system to the video within gocryptfs. Thumbnail does not show.
- Copy the video within gocryptfs to a "regular" file system. Thumbnail shows correctly.
- Create a symlink within gocryptfs to a video on a "regular" file system. Thumbnail shows correctly.
- Launch Dolphin from a terminal. No noteworthy logs.

STEPS TO REPRODUCE

1. Prepare a video file, MP4 or anything that's supported.
2. Observe that in a "normal" file system like exfat, ext4, or btrfs, Dolphin shows the video thumbnail correctly.
3. Create a plasma vault backed by gocryptfs, and copy the video file into it.
4. Observe that Dolphin does not show the thumbnail of this video file.
5. If possible, find a machine that is still on KDE frameworks 6.0. Observe that this problem does not exist.

SOFTWARE/OS VERSIONS

- Kernel: 6.8.2.arch1-1
- KDE Plasma: 6.0.3
- KDE Frameworks: 6.1.0
- QT: 6.7.0

Comment 1 Rean 2024-04-17 10:38:31 UTC

After this update, I noticed my network drive thumbnails were not showing anymore, and I figured out that the setting Skip previews for remote files above a certain size is set to no previews. That's the reason why it's not showing any previews, but I thought this setting was only for network drives. Why does it affect vaults? That seems like a bug. In Dolphin, go to Configure > Interface > Previews and increase the size of the remote file previews. See if that works for you as well.

Comment 2 SC 2024-04-17 21:02:30 UTC

(In reply to Rean from comment #1)
> After this update, I noticed my network drive thumbnails were not showing
> anymore, and I figured out that the setting Skip previews for remote files
> above a certain size is set to no previews. That's the reason why it's not
> showing any previews, but I thought this setting was only for network
> drives. Why does it affect vaults? That seems like a bug. In Dolphin, go to
> Configure > Interface > Previews and increase the size of the remote file
> previews. See if that works for you as well.

Ah yes. That does appear to be the issue. It seems like Dolphin is misclassifying gocryptfs mounts as network mounts.

I'm guessing, maybe it has always had this problem, but it has always been occluded by ffmpegthumbs's behaviour of disregarding the preview limit. Then in a recent update the preview limit is now respected, so the problem becomes visible.

Comment 3 axsc 2024-04-20 18:59:08 UTC

Same issue with encfs. The problem is that even if you increase the preview file size for remote files, the previews are never saved. That means if you're clicking through directories, it will have to reload all preview files every single time.