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IDProjectCategoryView StatusLast Update
0000432Cinelerra-GG[All Projects] Bugpublic2020-06-01 20:47
ReporterMatN Assigned Togoodguy  
Status closedResolutionfixed 
PlatformX86_64OSMint XFCEOS Version19.3
Product Version 
Target VersionFixed in Version2020-05 
Summary0000432: Perspective effect show single un-changed frame when it is used to rotating image horizontally
DescriptionI was playing with a horizontal rotating title, and when rotation through a side-on view you get 1 single unrotated frame. See attached video. I think this should not be.
CinGG version 2020-04 Mint
Steps To ReproduceSteps to reproduce:
- Create transparent HD still image with Gimp.
- Import this image in a new project, effects need some video. Adjust length as desired.
- Draw title effect on it, make half a screen width of text
- Draw Perspective effect on it, should be below the title effect.
- Menu Keyframe->Set to smooth
- Enable "generate keyframes when tweeking"
- Frame 0, Perspective effect->show controls, hit reset. This creates a keyframe.
- Move to the frame where the rotation should be 180 degrees, Perspective effect->Preset Edit. Set X1 to X4 to resp. 100, 0, 0, 100.
- Move to the frame where the rotation should be 360 (=0) degrees again. Perspective effect->show controls, hit reset. This creates a keyframe.
I did not bother with the Y values, for a proper effect they should vary a little too.
Now when you play it, at 90 or 130 degrees, when the text is seen from the side (thus invisible), you get 1 original unrotated frame.
In my case, the 90 degree point was frame 40 (1080p50 video), and frame 41 had the unrotated image. Frame 42 was Ok again.
TagsNo tags attached.




2020-06-01 20:47

manager   ~0003547

There are several places in the code that will print out this error - "for each frame I get a message "XMLTag::read_tag:326 tag "AUTO", end of buffer"in the terminal." We could not determine the cause and I could not reproduce the error using a static image as background. If you provide a session file, that generates the problem, gg will look at that.


2020-06-01 08:22

reporter   ~0003538

The 2020-05 released indeed fixed it. Thanks.
This can be closed.


2020-05-30 01:53

manager   ~0003520

GG made a mod to the program for the "singularity" case to show nothing for the single unrotated frame. Testing was minimal but it was checked into GIT so I will test more tomorrow.


2020-05-29 20:10

reporter   ~0003516

Thanks! Indeed, deleting a single frame before the first edge-on frame makes it work properly.
I tried to put an extra keyframe on the frame that displayed the full frame, but had difficulties getting the proper values.
Maybe it is worth putting this workaround or caveat in the manual?

If the picture is fully side-on, maybe nothing should be displayed, or just a vertical line? I have not tested any effects of the shadow.

While I am at it, the effect's control panel does not show the point number, just "current X and Y". Is it possible to indicate the point number (1-4)? It is difficult to adjust the points when they become close together. The "preset edit" screen shows the number.

On a last note, when I play the video showing the problem, for each frame I get a message "XMLTag::read_tag:326 tag "AUTO", end of buffer"in the terminal. Maybe because I used a static image as background?


2020-05-28 23:09

manager   ~0003504

Last edited: 2020-05-29 03:59

View 2 revisions

This is a case where you end up in the middle with divide by 0. You have to set the X value for the middle keyframe instead of to 0, to a little more, such as .01.

And now a word from GG:
The interpolated X1..X4 auto coordinates used by perspective eventually have x1==x2, x3==x4, so that all points x are scaled by zero. You also could tweak the frame count so that it is even, so that the center is not over the point where x1==x2, x3==x4, or perturb the midpoint position a little so that the answers are not exactly zero.

Any suggestions for what to do in the case of divide by 0?



2020-05-15 11:06


Perspective_issue.mp4 (452,304 bytes)

Issue History

Date Modified Username Field Change
2020-05-15 11:06 MatN New Issue
2020-05-15 11:06 MatN File Added: Perspective_issue.mp4
2020-05-28 22:50 PhyllisSmith Assigned To => goodguy
2020-05-28 22:50 PhyllisSmith Status new => assigned
2020-05-28 23:09 PhyllisSmith Status assigned => feedback
2020-05-28 23:09 PhyllisSmith Note Added: 0003504
2020-05-29 03:59 PhyllisSmith Note Edited: 0003504 View Revisions
2020-05-29 20:10 MatN Note Added: 0003516
2020-05-29 20:10 MatN Status feedback => assigned
2020-05-30 01:53 PhyllisSmith Note Added: 0003520
2020-06-01 08:22 MatN Note Added: 0003538
2020-06-01 20:45 PhyllisSmith Status assigned => resolved
2020-06-01 20:45 PhyllisSmith Resolution open => fixed
2020-06-01 20:45 PhyllisSmith Fixed in Version => 2020-05
2020-06-01 20:47 PhyllisSmith Status resolved => closed
2020-06-01 20:47 PhyllisSmith Note Added: 0003547