[Risolto] Different dimensions images.

Thanks @sparkill, it is more clear, now. It is not a size distortion problem, as I thought, but
an alpha channel problem.

Alpha channel must have something where working on.
In the timeline, add a new Video track below your main Video track where there are PNG images.
In the new Video track insert the Alpha Effect (plugin) and set the Alpha value to zero.
To understand what I am writing take a look at the screencast in the link:
https://transfer.sh/d4hLQl/Cin_20220630_PNG_and_alphaChannel_again.ogv
(It will be deleted after 15 days from now)

The screencast shows the same PNG (your PNG) for three times. In the Video track below (VFX_BKG) you can see, from left to right in the timeline: NO effect for the first PNG, the Alpha effect for the second PNG and the Gradient effect for the third PNG.
The Compositor is shown on the right of the screecast. The transparency (alpha channel) works good where there are Alpha and Gradient effects.

If you want to read about the alpha channel problem and its workaround, it has been discussed in MantisBT at https://www.cinelerra-gg.org/bugtracker/view.php?id=558#c4672 .
Phyllis wrote that in the Manual. Link at https://cinelerra-gg.org/download/CinelerraGG_Manual/FAQ_Known_Problems_Workarou.html

Maybe a different thread's Title would be better?

@sparkill

@IgorBeg

@andreapaz

Any Solution

"Images with odd dimensions may not decode properly"

the images were desecrated as an oil painting

If I remember correctly, odd dimensions means "not divisible by 2".  So dimensions of 352x240 are OK, but 351x240 is "odd dimensions" since 351 is not an even number.  I have occasionally had this error but have not noticed it being of concern.  Do you want to send a small example for someone else to look at?

Probably someone has a good solution though.

@sparkill

I found this I did not understand too much.

https://www.cinelerra-gg.org/bugtracker/view.php?id=237

Lots of notes to read in the above but all it means is that you can set the background color in the Compositor window so you can see exactly what your video dimensions are.  The default is black, so it is often hard to see.  To demonstrate the modification created as a result of Bug Tracker issue #237, do the following:

1) load a video and make sure you can see some frame in the compositor

2) in the main window, use the Settings pulldown and choose the Format option to use a bigger dimension than what your video is so you see it shrink in size in the compositor

3) now use the Settings pulldown and choose the Preferences options; in that menu pick the Appearance tab and in the Color section where it shows "Composer BG  color" change from the default of black to some visible color, then click OK checkmark and another click OK checkmark.  Note the compositor boundary outside your actual image turns color so you can easily see where your image ends.

@phylsmith2004

this is the image when exporting to cingg is distorted. but in gimp it's fine.

strange pixels appear in the peak.

I try to make a sequence.
I speculate it is an ffmpeg problem.

@phylsmith2004

thanks for the explanation. It was the only thing I found about my problem.

Although it is different, it is good to know! 🙂

apparently I need a background for PNG with alpha channel.

RGB, RGBA, RGBA-FLOAT, YUVA and YUV. they need it.
RGB-FLOAT works without artifacts. I don't need a background.

I have to investigate more.

@sparkill wrote:

this is the image when exporting to cingg is distorted.

Your image is 598x588 pixels. What is your Format project (size, fps)?

@IgorBeg

1080x1080 50FPS
1092x1248 and 50FPS
I also tried the image size 598x588 25FPS

I also rendered the images with ffmpeg in the terminal. (same result)

I think that my tests don't answer to your "Images with odd dimensions may not decode properly" question but...
Why do we have to use an odd size for an image? Better avoid if you can, I think.

I have done two tests.
First test using a 1024x1024 PNG file with alpha channel. Format project YUVA-8bit (or RGBA-8bit), 1024x1024@25fps.
Render: mp4 | h264.mp4 | Pixels= yuv420p
Output: GOOD

Second test using your 598x588 PNG file (with alpha channel). Format project YUVA-8bit (or RGBA-8bit), 598x588@25fps.
Render: mp4 | h264.mp4 | Pixels= yuv420p
Output: GOOD

Tested with:
- CinGG-20220630-x86_64-older_distros.AppImage
- cinelerra-5.1-ub16.04-20201031.x86_64

Maybe more info are needed. So, what is your goal? Using some PNG images to create an animation?

Posted by: @igorbeg

Maybe more info are needed. So, what is your goal? Using some PNG images to create an animation?

yes, sequences with alpha channel and then I export them to alpha channel.

render: user_ffvhuff.mkv + yuva420

RGBA-8Bits "Compositor window" shows it badly distorted with artifacts
the rendering comes out fine in RGBA-8bits format. (no artifacts and distortion)
RGB-FLOAT displays image correctly in compositor but exports without alpha channel. (as expected)

I feel like it's FFmpeg problem and not Cingg.
using the terminal the same result is expected.

export sequence in yuv420 with mp4 (distorted with artifacts) as in the image. compositor.png

export in (qtrle/FFVHUFF/HUFFYUV) perfect sequence with alpha channel.

Thank you very much for the support and clarifications! @igorbeg

works!!! now the "alpha" plugin makes sense. 🙂

the compositor shows it correctly!

the final render works as expected, with no distortion or artifacts!

Posted by: @igorbeg

Maybe a different thread's Title would be better?

yes, @phylsmith2004 Please or can some moderator change the title? (I don't have any options.)

"Alpha Channel in Cinelerra GG Distortions and Artifacts"

I am glad it works as expected, @sparkill. Thanks!

Off Topic:
On the bottom-right of the topics there is a TopDown menu with three items: Most Voted, Oldest, Newest. It seems no works anymore. I wanted "Oldest". Because sparkill voted my previous post, that post is up in the order. So, I voted my previous post with down button (from 1 to 0) to see if "Oldest" works or less. Sorry.

@phylsmith2004
Off Topic:
Sorry, Phyllis. I wrote really bad.
On the first Topic of sparkill (on the top of the list of all topics) there is a PullDown button (on the bottom right) with three items: Most Voted, Oldest, Newest. It is always set to "Most Voted".
Usually I change the option from "Most Voted" to "Oldest" to see the posts in chronological order. But, using "Oldest" option, my post https://www.cinelerra-gg.org/forum/help-video/different-dimensions-images/#post-2207 is second on the list from the top. It is strange, I think.

@IgorBeg

I think there is a confusion.
I have the "Solution" option "Solved" so it was put on the top✅

Sparkill wrote:

I have the "Solution" option "Solved" so it was put on the top✅

So, the filter "Oldest" doesn't work on the Solved post? It is a pity, I think. If I were reading this thread for the first time, it would be difficult for me to follow this thread except in chronological order.

Thanks, sparkill.