Fedora Linux 43: in AppImage, transitions show all black.

[huubvanniekerk]

Describe the bug:
When placing a transition, e.g. "Blinds sliding" on a track with clips, the transition doens't show "Blinds sliding" but only black. Same with other transitions.

Steps to reproduce the behavior:

1. Go to Transitions
2. Select any transition
3. Drag the selected transition to the desired place on the track
4. Watch the transition

Expected behavior:
In case of the "Blinds sliding", I expect to see the blinds sliding for the time I want, e.g. 1 second.

System Details:

• OpenShot Version [e.g. 2.4.3]: OpenShot-v3.4.0-daily-14916-47b30812-a76e176a-x86_64.AppImage and OpenShot-v3.4.0-daily-14960-47b30812-a76e176a-x86_64.AppImage
• Operating System / Distro: Fedora Linux 43

I can't tell since when this problem actually has started, sinice this is the first time in months that I use transitions again.

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[huubvanniekerk]

Addition 1: after continuing editing and placing 15 transitions which all show black, transition 16th shows the "Blinds sliding" effect as I expect it should do. The next 5 transitions, no matter what transition is used, show all black again and then, apparently random, 1 good transition, followed by more black transitions.

[huubvanniekerk]

Addition 2: it seems that the transition, other than I was used to, doesn't always start at 0. Some do start at 0 (as I want) with the blinds visible, with others the visibility of the blinds (or other transitions) starts after 4 to 6 seconds inside the transition. And a transition longer than 1 second is undesired, having clips varying between 5 seconds to 4 minutes.

[huubvanniekerk]

Addition 3: I have found a work-around for now. Replace each not-working transition on the timeline by a transition of the standard 10 seconds. Then put the middle of the transition on the desired place and test whether or not the newly placed transition actually works. If so, shrink (i.e. drag the side of) the transition from both sides until the desired length of 1 second is reached and the transition still works. Rather cumbersome to do, but better this way than no (working) transitions.

[Colorjet3]

Hello @huubvanniekerk. I am about to start doing some testing to replicate your issue and wanted some additional information.

1. In your steps to reproduce you say drag a transition to the desired place on the track. It may be obvious, but adding a transition onto a track that has no clip will not do anything. If you preview the transition by itself all you will see is black.
2. When you drag a transition on top of a clip, it will automatically Fade In. This means that during the preview, whatever clip you overlayed, it will be dark at the beginning and slowly show up as the transition Brightness (attribute) goes from +1.00 to -1.00.

So please give this a try as a test (I am testing in Windows 11 Pro right now and will get to Fedora AppImage shortly):

1. Start a new project.
2. Drag 5 emojis from the Emojis tab onto Track 5. You can have them snapped together or gaps in between. It shouldn't matter. Note that Emojis by default are 10 seconds long.
3. Drag any Transition (play with 5 different types, one for each of the emojis for testing) onto the emojis on Track 5. Note that transitions are 10 seconds long also and they should cover the entire emoji clip unless you choose not to cover the entire Emoji. for now cover the entire Emoji.
4. Now preview them and note that the transitions Fade in and as the playhead reaches the halfway point of the clip it slowly disappears.
5. This should happen to all the emoji clips from step 3.

Confirm that this worked for you.

If it worked then try the same thing with other file types (.jpg, .mov, etc.).

If you are doing something different then please provide me with detailed step-by-step instructions and don't assume anything. Tell me exactly what you are doing so I can replicate it.

From the OpenShot User Guide

Transitions
A transition is used to gradually fade (or wipe) between two clip images. In OpenShot, transitions are represented by blue, rounded rectangles on the timeline. They are automatically created when you overlap two clips, and can be added manually by dragging one onto the timeline from the Transitions panel. A transition must be placed on top of a clip (overlapping it), with the most common location being the beginning or end of a clip.

NOTE: Transitions do not affect audio, so if you are intending to fade in/out the audio volume of a clip, you must adjust the volume clip property. See Clip Properties

[Colorjet3]

Just tested with the steps I provided in my response above in Fedora 43 and Ubuntu 25.10 with the same positive results. I also tested with *.mov files and same behavior.

I will wait for your response and we can troubleshoot further if needed.

[huubvanniekerk]

@Colorjet3

Yes, I'm aware of the fact that a transition on a track without any clips won't work. It was a mistake I made when I was first beginning to use transitions and wondered why I didn't see anything of it. For this video, I only used *.mov files, no *.ogg. Usually I use both *.mov and *.ogg without transitions, but in some cases only *.mov with transitions.

For a transition to work, yes, it fades in and out. And my preferred transition is "Blinds sliding".

For your test: I used the first 5 emojis and first 5 transitions. That worked out well, depending a bit on the transition. For your description, I had to use the reversed transitions, but it worked.

What happens when it goes wrong:
I place the middle of the transition on the track with clips, exactly where 2 clips meet. I put the needle at a random position in the transition and all I see is black. No matter if the transaction length is just 1 second or 10 seconds or some time in between, the screen (i.e. preview) goes all black from the beginning of the transition right until the end of it. At that moment, you see the content of the next clip. With the audio, nothing is wrong. So from the audio you will hear when you pass on to the next clip.
I also tested it by just placing a transition at a random place on a clip. You hear the audio, but during the transition, the preview is black. Length of the transition doesn't matter.

What happens when it goes fine:
I place the middle of a transition on the track with clips, exactly where 2 clips meet. I put the needle at a random position in the transition and I see the effect of the transition. I want the transition to be only 1 second, because it can happen that a clip is only 5 seconds. In order to create the 1 second transition, I drag each side of the transition towards the point where the 2 clips meet and during this I check if I still can see the transition happening. Finally, using the transition properties, I make sure the end (and as such, its length) is 1 second.

What happened prior to this, is that I put the transition right under the place where 2 clips meet, via properties make it 1 second and put the transition on the track with the clips. I've done it quite a few times and never had non-working transitions before.

[Colorjet3]

Hello @huubvanniekerk The information you provided really helped. I am experiencing the issue you describe pluss additional odd behaviors.

1. When I shrink a transition to 1 second I notice:
   a. The end keyframe disappears and never returns even if I change the transition length back to 10 seconds.
   b. When I shrink the transition to 1 seconds, the expectation is that the transition adjusts the timing, perfectly, for 1 second. However, this is not happening. When watching/monitoring the Brightness attribute while nudging the playhead 1 frame at a time using the right arrow key, I noticed that when I get to the 1/2 way point on the tranisition that the value of the Brightness attribute is way off.

2. If the Transition lenght is higher than 2 seconds that the keyframe at the end of the transistion stays visible and the timing of the transistion is adjusted properly.

This is also consistent in Ubuntu 25.10 using the AppImage.

I will submit a bug in the queue for the lead developer to look into this.

[Colorjet3]

Hello @huubvanniekerk

In the process of submitting this issue to the queue I noticed that if I adjust the duration of the transition using the mouse, then everthing works fine. However, if I manually change the End attribute then things break.

I realize it is challenging to get the duration correct using the mouse. I had to zoom in enough where it was possible to adjust the Transition to 1 seconds in Duration (Start = 0, End = 1). Once I did this all worked well.

Can you please confirm this for me in your environment? I need to ensure that I submit the proper information for the lead developer.

[huubvanniekerk]

Hellop @Colorjet3 I can confirm your finding with adjusting the duration.

Editing the end in the properties, breaks the transition.

Dragging the sides using the mouse until it is (almost) 1 and then eventually correcting it to exactly 1 second in the properties, works well.

And yes, dragging the sides takes time and is challenging. You have to zoom in quite a bit, which is a challenge on it own. A zoom in/out function (e.g. using Ctrl +/-) would be helpful (unless it's already there but don't know how?)

[Colorjet3]

THank you @huubvanniekerk for confirming. Two easy ways to zoom in/ou:

Option 1: If you have a mouse with a scroll wheel, all you have to do is hover over the timeline, press and hold the CTRL key and use the scroll wheel to zoom in/out.

Option 2: Pressing the "-" (negative sign) / "=" (equal sign) on a keyboard will zoom in/out as well.

[huubvanniekerk]

@Colorjet3 Thank you for indicating the zoom options. Really helpful.

[Colorjet3]

@Colorjet3 Thank you for indicating the zoom options. Really helpful.

You are welcome @huubvanniekerk I also should mention that double clicking on the zoom bar (just above the top most track, will expand/shrink the timeline as well. Double click once and it will expand, double click again and it will return to the way you had it.

[huubvanniekerk]

@Colorjet3 Once again, thank you.