[GH-ISSUE #1398] [Bug] Importing Image Sequences Is Extremely Slow #3655

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opened 2026-03-01 19:14:34 +03:00 by kerem · 0 comments

kerem commented

2026-03-01 19:14:34 +03:00

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Originally created by @zarstensen on GitHub (Jul 1, 2025).
Original GitHub issue: https://github.com/NickeManarin/ScreenToGif/issues/1398

Originally assigned to: @NickeManarin on GitHub.

Describe the bug
Importing an image sequence consisting of 3600 (1920 x 1080; ~8MB) PNG images takes a very long time.
The most recent attempt i made took more than 20 minutes, meaning each image took at least 1/3 of a second to import.

Another attempt with a subset of 50 images from the same image sequence took around 14 seconds, which again means each image took ~1/3 of a second to import.

To Reproduce

Go to 'Load'
Select a large image sequence (in theory any size would suffice, but the larger the more noticeable the issue is).
Observe the issue and wait for a long while.

Expected behavior
Taking 1/3 of a second for an image to be imported seems like a rather long time to me, ideally something should be optimized (see additional context for my uninformed take :) ) so this is not as slow.

Desktop (please complete the following information):

OS: Windows 10
Version 2.41.3

Additional context
I ran a rough profiling of the code base, and it seems most of the runtime is spent on decoding and re-encoding the image sequence into PNG's, which seems rather redundant considering the original image sequence already consisted of PNG's.
Link to source code i am referring to
Could a check be made somewhere if the source image sequence can just be directly copied instead of this de-re encoding to speed up the process, as a possible optimization?

Originally created by @zarstensen on GitHub (Jul 1, 2025). Original GitHub issue: https://github.com/NickeManarin/ScreenToGif/issues/1398 Originally assigned to: @NickeManarin on GitHub. **Describe the bug** Importing an image sequence consisting of 3600 (1920 x 1080; ~8MB) PNG images takes a very long time. The most recent attempt i made took more than 20 minutes, meaning each image took at least 1/3 of a second to import. Another attempt with a subset of 50 images from the same image sequence took around 14 seconds, which again means each image took ~1/3 of a second to import. **To Reproduce** - Go to 'Load' - Select a large image sequence (in theory any size would suffice, but the larger the more noticeable the issue is). - Observe the issue and wait for a long while. **Expected behavior** Taking 1/3 of a second for an image to be imported seems like a rather long time to me, ideally something should be optimized (see additional context for my uninformed take :) ) so this is not as slow. **Desktop (please complete the following information):** - OS: Windows 10 - Version 2.41.3 **Additional context** I ran a rough profiling of the code base, and it seems most of the runtime is spent on decoding and re-encoding the image sequence into PNG's, which seems rather redundant considering the original image sequence already consisted of PNG's. [Link to source code i am referring to](https://github.com/NickeManarin/ScreenToGif/blob/3657cd5326b8bd569be8d03f1d752f3eefb4a04b/ScreenToGif/Windows/Editor.xaml.cs#L4308C1-L4317C14) Could a check be made somewhere if the source image sequence can just be directly copied instead of this de-re encoding to speed up the process, as a possible optimization?

kerem

2026-03-01 19:14:34 +03:00

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starred/ScreenToGif#3655

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