Bug 474851

Summary: Light effect for multitracks with "Rotate" & "Wipe
Product: [Applications] kdenlive Reporter: fehler-im-programm
Component: Video Effects & TransitionsAssignee: Jean-Baptiste Mardelle <jb>
Status: RESOLVED FIXED    
Severity: normal CC: berndmj
Priority: NOR    
Version First Reported In: 23.08.1   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Projectfile - Light effect for multitracks with "Rotate" & "Wipe
Video - Light effect for multitracks with "Rotate" & "Wipe"
testbild dunkel.png
Testbild dunkel.jpg
Bug Lichteffekt bei Mehrspuren mit 'Rotieren' & 'Wipe'.kdenlive
Girl Faces.mp4
Girl Faces2.mp4
attachment-2018581-0.html

Description fehler-im-programm 2023-09-25 10:53:20 UTC
Created attachment 161853 [details]
Projectfile - Light effect for multitracks with "Rotate" & "Wipe

STEPS TO REPRODUCE
1. Insert third Track
2. Insert a dark, narrow Clip
3. Add "Rotieren" in all Clips
4. Both Clips must see (with Rotieren "Offset X")
5. Add "Wipe" over the Clip on 3. track

See also Attachment projectfile!

OBSERVED RESULT
Right Clip becomes darker and again lighter

EXPECTED RESULT
No "light effect"
Comment 1 fehler-im-programm 2023-09-25 10:55:54 UTC
Created attachment 161854 [details]
Video - Light effect for multitracks with "Rotate" & "Wipe"
Comment 2 Bernd 2023-09-28 00:06:18 UTC
> EXPECTED RESULT
> No "light effect"

Please specify what you are trying to achieve,  expect to see, and what the "light effect" is supposed to be.

I d/l the project file but it is missing the 'Testbild dunkel.jpg' file so I took a frame of the `.mp4` you provided instead. The 'Wipe' transition has a *dissolve* wipe method, and in my setup the transition does what it is supposed to do: dissolve from one track to the other.
Comment 3 fehler-im-programm 2023-09-28 10:06:13 UTC
Created attachment 161927 [details]
testbild dunkel.png
Comment 4 fehler-im-programm 2023-09-28 10:28:00 UTC
Created attachment 161928 [details]
Testbild dunkel.jpg

*Hello Bernd,*

I expect *NO* "Light Effect" (/EXPECTED RESULT No "light effect"/). Is 
nonsense with the "Rotate" effect.


Attachment: Testbild dunkel.jpg & Project file again.


*Regards Johannes*


Am 28.09.23 um 02:06 schrieb Bernd:
> https://bugs.kde.org/show_bug.cgi?id=474851
>
> Bernd<berndmj@yahoo.com>  changed:
>
>             What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                   CC|                            |berndmj@yahoo.com
>
> --- Comment #2 from Bernd<berndmj@yahoo.com>  ---
>> EXPECTED RESULT
>> No "light effect"
> Please specify what you are trying to achieve,  expect to see, and what the
> "light effect" is supposed to be.
>
> I d/l the project file but it is missing the 'Testbild dunkel.jpg' file so I
> took a frame of the `.mp4` you provided instead. The 'Wipe' transition has a
> *dissolve* wipe method, and in my setup the transition does what it is supposed
> to do: dissolve from one track to the other.
>
Comment 5 fehler-im-programm 2023-09-28 10:28:00 UTC
Created attachment 161929 [details]
Bug Lichteffekt bei Mehrspuren mit 'Rotieren' & 'Wipe'.kdenlive
Comment 6 Bernd 2023-09-28 15:09:24 UTC
(In reply to fehler-im-programm from comment #4)
> I expect *NO* "Light Effect" (/EXPECTED RESULT No "light effect"/). Is 
> nonsense with the "Rotate" effect.

If you do not want to have the "getting darker and then lighter" effect then change the clips in the timeline.

The way you have put the clips in the timeline and used the Wipe transition this is bound to happen. You have not explained what you are trying to achieve so I am guessing here: If you want to dissolve from one image to another whereby the first is on the left and rotated so that the girl faces left, use only tracks V2 and V1 with a Dissolve transition (not a Wipe transition!) where Reverse is checked. This would fade out the left portion and fade in the right side which is the original image offset to the right.

In your setup V3 and V1 are the same but the Wipe transition is between V3 and V2. While strictly speaking the tracks are not layers like in Gimp or Photoshop the track with the highest number "covers" all tracks with lower numbers. There is a very well written blog post about this here: http://thediveo-e.blogspot.com/2014/07/kdenlive-timeline-illustrated-part-1.html
When Kdenlive applies the Wipe effect from V3 and V2 it "wipes out" V3 by compositing less and less brightness from V3 with more and more nothing from V2 (remember that you offset the image on V2 to the left leaving nothing on the right side of the frame) and then composites that result with V1. There is an issue with the underlying 'affine' filter that does not process the alpha channel correctly (Position and Zoom has the same issue).

If you need the current setup with three tracks use the Flippo effect (or Flip Horizontally) and a Transform effect on the clips in V3 and V2 where X=-320, a Transform effect with X=320 on the clip in V2, and a Wipe transition between V2 and V1. But then the Wipe doesn't do anything visible.
Comment 7 fehler-im-programm 2023-09-28 17:14:27 UTC
Created attachment 161933 [details]
Girl Faces.mp4

*Hello Bernd,*

thank you very much for your feedback.


You write:

/The way you have put the clips in the timeline and used the Wipe 
transition this is bound to happen. You have not explained what you are 
trying to achieve so I am guessing here: If you want to dissolve from 
one image to another whereby the first is on the left and rotated so 
that the girl faces left, use only tracks V2 and V1 with a Dissolve 
transition (not a Wipe transition!) where Reverse is checked. This would 
fade out the left portion and fade in the right side which is the 
original image offset to the right:
/

No, I had used the Glow effect and wondered about the strange "light 
effect" on the right picture.

Removing the glow effect did not help.

I then realized that the combination of "Rotate & Wipe Effect" plus 
multi-tracks were responsible for this and therefore reported the bug.

I solved the whole thing with "Transparency" (see video attached). This 
is how it should look. First brighter, then back to normal brightness.


*Regards Johannes*


Am 28.09.23 um 17:09 schrieb Bernd:
> https://bugs.kde.org/show_bug.cgi?id=474851
>
> --- Comment #6 from Bernd<berndmj@yahoo.com>  ---
> (In reply to fehler-im-programm from comment #4)
>> I expect *NO* "Light Effect" (/EXPECTED RESULT No "light effect"/). Is
>> nonsense with the "Rotate" effect.
> If you do not want to have the "getting darker and then lighter" effect then
> change the clips in the timeline.
>
> The way you have put the clips in the timeline and used the Wipe transition
> this is bound to happen. You have not explained what you are trying to achieve
> so I am guessing here: If you want to dissolve from one image to another
> whereby the first is on the left and rotated so that the girl faces left, use
> only tracks V2 and V1 with a Dissolve transition (not a Wipe transition!) where
> Reverse is checked. This would fade out the left portion and fade in the right
> side which is the original image offset to the right.
>
> In your setup V3 and V1 are the same but the Wipe transition is between V3 and
> V2. While strictly speaking the tracks are not layers like in Gimp or Photoshop
> the track with the highest number "covers" all tracks with lower numbers. There
> is a very well written blog post about this here:
> http://thediveo-e.blogspot.com/2014/07/kdenlive-timeline-illustrated-part-1.html
> When Kdenlive applies the Wipe effect from V3 and V2 it "wipes out" V3 by
> compositing less and less brightness from V3 with more and more nothing from V2
> (remember that you offset the image on V2 to the left leaving nothing on the
> right side of the frame) and then composites that result with V1. There is an
> issue with the underlying 'affine' filter that does not process the alpha
> channel correctly (Position and Zoom has the same issue).
>
> If you need the current setup with three tracks use the Flippo effect (or Flip
> Horizontally) and a Transform effect on the clips in V3 and V2 where X=-320, a
> Transform effect with X=320 on the clip in V2, and a Wipe transition between V2
> and V1. But then the Wipe doesn't do anything visible.
>
Comment 8 Bernd 2023-09-28 18:52:09 UTC
(In reply to fehler-im-programm from comment #7)
> Created attachment 161933 [details]
> Girl Faces.mp4
> 
> *Hello Bernd,*
> 
> thank you very much for your feedback.
> 
> 
> You write:
> 
> /The way you have put the clips in the timeline and used the Wipe 
> transition this is bound to happen. You have not explained what you are 
> trying to achieve so I am guessing here: If you want to dissolve from 
> one image to another whereby the first is on the left and rotated so 
> that the girl faces left, use only tracks V2 and V1 with a Dissolve 
> transition (not a Wipe transition!) where Reverse is checked. This would 
> fade out the left portion and fade in the right side which is the 
> original image offset to the right:
> /
> 
> No, I had used the Glow effect and wondered about the strange "light 
> effect" on the right picture.
> 
> Removing the glow effect did not help.
> 
> I then realized that the combination of "Rotate & Wipe Effect" plus 
> multi-tracks were responsible for this and therefore reported the bug.
> 
> I solved the whole thing with "Transparency" (see video attached). This 
> is how it should look. First brighter, then back to normal brightness.
> 
> 
> *Regards Johannes*

I am glad you achieved what you were trying to achieve. Is this bug report still needed? If not please change the status to 'RESOLVED'.

I must admit I am still confused by your three-track setup. I get two but don't understand the need for the third. The "brighter, then normal" effect is also doable with Exposure.
Comment 9 fehler-im-programm 2023-09-28 19:43:30 UTC
Created attachment 161935 [details]
Girl Faces2.mp4

*Hello Bernd,*

Status = Resolved!


You write:

/I must admit I am still confused by your three-track setup. I get two 
but don't understand the need for the third. The "brighter, then normal" 
effect is also doable with Exposure./

Just not. "Brightness" makes the WHOLE image bright. I wanted only the 
faces to be bright.

See attachment (first GLOW, then BRIGHTNESS).


*Regards Johannes*


Am 28.09.23 um 20:52 schrieb Bernd:
> https://bugs.kde.org/show_bug.cgi?id=474851
>
> --- Comment #8 from Bernd<berndmj@yahoo.com>  ---
> (In reply to fehler-im-programm from comment #7)
>> Created attachment 161933 [details]
>> Girl Faces.mp4
>>
>> *Hello Bernd,*
>>
>> thank you very much for your feedback.
>>
>>
>> You write:
>>
>> /The way you have put the clips in the timeline and used the Wipe
>> transition this is bound to happen. You have not explained what you are
>> trying to achieve so I am guessing here: If you want to dissolve from
>> one image to another whereby the first is on the left and rotated so
>> that the girl faces left, use only tracks V2 and V1 with a Dissolve
>> transition (not a Wipe transition!) where Reverse is checked. This would
>> fade out the left portion and fade in the right side which is the
>> original image offset to the right:
>> /
>>
>> No, I had used the Glow effect and wondered about the strange "light
>> effect" on the right picture.
>>
>> Removing the glow effect did not help.
>>
>> I then realized that the combination of "Rotate & Wipe Effect" plus
>> multi-tracks were responsible for this and therefore reported the bug.
>>
>> I solved the whole thing with "Transparency" (see video attached). This
>> is how it should look. First brighter, then back to normal brightness.
>>
>>
>> *Regards Johannes*
> I am glad you achieved what you were trying to achieve. Is this bug report
> still needed? If not please change the status to 'RESOLVED'.
>
> I must admit I am still confused by your three-track setup. I get two but don't
> understand the need for the third. The "brighter, then normal" effect is also
> doable with Exposure.
>
Comment 10 Bernd 2023-09-28 21:07:48 UTC
(In reply to fehler-im-programm from comment #9)
> Just not. "Brightness" makes the WHOLE image bright. I wanted only the 
> faces to be bright.

I agree that the BRIGHTNESS effect makes the whole image brighter. That's why I said use the EXPOSURE effect as it brightens only the already EXPOSED parts, i.e. the faces.
Comment 11 fehler-im-programm 2023-09-28 21:43:24 UTC
Created attachment 161938 [details]
attachment-2018581-0.html

*Hello Bernd,*

thank you very much for your feedback again.


You write:

/I agree that the BRIGHTNESS effect makes the whole image brighter. 
That's why I said use the EXPOSURE effect as it brightens only the 
already EXPOSED parts, i.e. the faces./

Yes, that's right. I did not know this effect yet. And in the case of 
"Glow" makes the multitracks obsolete.

Thanks for that!

This is the problem with the *Translator*. "Exposure" was suggested to 
me as "Belichtung", which I mistook as "Helligkeit". Maybe I should 
report the bugs in "German". 🙂


*Regards Johannes*


Am 28.09.23 um 23:07 schrieb Bernd:
> https://bugs.kde.org/show_bug.cgi?id=474851
>
> --- Comment #10 from Bernd<berndmj@yahoo.com>  ---
> (In reply to fehler-im-programm from comment #9)
>> Just not. "Brightness" makes the WHOLE image bright. I wanted only the
>> faces to be bright.
> I agree that the BRIGHTNESS effect makes the whole image brighter. That's why I
> said use the EXPOSURE effect as it brightens only the already EXPOSED parts,
> i.e. the faces.
>