Bug 500623 - Transform: unreasonably low resolution when preview resolution is set lower than 1:1 and proxy is used
Summary: Transform: unreasonably low resolution when preview resolution is set lower t...
Status: REPORTED
Alias: None
Product: kdenlive
Classification: Applications
Component: Video Effects & Transitions (show other bugs)
Version: 24.12.2
Platform: Microsoft Windows Microsoft Windows
: NOR normal
Target Milestone: ---
Assignee: Jean-Baptiste Mardelle
URL:
Keywords: triaged
Depends on:
Blocks:
 
Reported: 2025-02-23 13:58 UTC by Andrey
Modified: 2025-03-26 17:57 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
Example (1.60 MB, image/png)
2025-02-23 13:58 UTC, Andrey
Details

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Description Andrey 2025-02-23 13:58:28 UTC
Created attachment 178773 [details]
Example

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SUMMARY


STEPS TO REPRODUCE
1. Make a 2160p project
2. Insert a 2160p H264 clip
3. Make a proxy of the clip
4. Insert the clip into the timeline
5. Add transform to the clip
6. Switch preview resolution to 720p

OBSERVED RESULT

Preview resolution is unreasonably low. Once Transform is disabled the resolution becomes normal.

EXPECTED RESULT

Adequate preview resolution when using the Transform effect.

SOFTWARE/OS VERSIONS

Kdenlive: 24.12.2
MLT: 7.30.0
FFmpeg
KDE Frameworks: 6.11.0
Qt: Using 6.8.2 and built against 6.8.2
KDE Flatpak runtime (Xcb)
Build ABI: x86_64-little_endian-lp64
Kernel: linux 6.11.10+bpo-amd64
Comment 1 Andrey 2025-02-23 14:00:01 UTC
I think it's not "quarter of the resolution" but more like a thumbnail resolution.
Comment 2 Andrey 2025-03-18 10:52:18 UTC
The issue is still present in 24.12.3.
Comment 3 emohr 2025-03-22 17:02:59 UTC
Thank you for reporting. I can confirm the issue. Following your steps. 
I tried with different proxy sizes. As soon as the transform effect is enabled on the timeline clip or on the bin clip it gets blurry.
Comment 4 Jean-Baptiste Mardelle 2025-03-25 10:06:58 UTC
Fixed in commit:
https://github.com/mltframework/mlt/commit/11023db52a8a4d80095e13212aabb1d13bdcafe4
Comment 5 editwithmyfeet 2025-03-26 17:18:21 UTC
Version 24.12.2 (installed version)
Os Windows 11

Hi, 
For Windows users (if this can help) : Since i have no skill to compile, i proceeded with a solution that's a bit tricky.
I switched libmltqt6.dll between two kdenlive versions. I took libmltqt6.dll from 24.12.0 and placed it to C:\Program Files\kdenlive\lib\mlt\ 
in 24.12.2 version.
Now i get a decent preview when using transform filter. 
Keep up the good work to make kdenlive even more reliable! Waiting for 25.04 to be released.

(In reply to Jean-Baptiste Mardelle from comment #4)
> Fixed in commit:
> https://github.com/mltframework/mlt/commit/
> 11023db52a8a4d80095e13212aabb1d13bdcafe4
Comment 6 Andrey 2025-03-26 17:57:32 UTC
Thank you very much for fixing this! Waiting for the next release to test it out (I'm on Linux).