White border not really white


I’m a beginner in shotcut. It’s very intuitive, but I encounter a problem with a white border mask around my videos. So perhaps I use it the wrong way.

I have a video, and I add in a second layer the mask (a png file with only white border, the other part of the file is transparent). I join the caption of the configuration and the files.
You can see that in the preview area, the border is white, as in the png file. Preview image export joined.
But after rendering the video (I use the YouTube preset without any modification), the white border is light gray, and when uploading to youtube, the difference between the white background of the page and the border of the video is very visible.

Original file : white is #ffffff, rendered file, white is something like #eaeaea

But more than the border, when analyzing the two images (from the rendering window, and from the target file), the target video seem to be insipid. It’s not only the border, seems to be all the video that loosed contrast and has some fog on it.

Do I miss something in the parameters ?

Thanks a lot in advance for your help.

As a new user, I can post only one picture with my message… So I merged the three into one :wink: Hope it will be visible.

What program are you using to view the final video? Are you opening it back in Shotcut? Or are you viewing it with some other video player?

Also, providing information about your Shotcut version and computer will be helpful.


My shotcut version is 17.09.04, running in win10.
My capture was from MediaPlayerClassic-HC.
I tried to play the video file in VLC, and it was the same.

I didn’t try to open it again in shotcut, so I just did it, and the white borders… are white.
Can’t understand.

I just uploaded it in youtube to show the problem… I would like to have no color difference between the white background of youtube… and the border of the video.
I would prefer a good rendering in youtube than in my video player. Cause I can tune my video player… but the video still appears gray in youtube.

Can you post a screenshot of your export settings? Particularly the “video” and “codec” tabs?

Also, your version of Shotcut is almost a year old. It would be worthwhile to try the latest version. If you do, I would suggest that you download the portable version (while keeping your current version installed) and then use the portable version to open a copy of your .mlt file so that you don’t risk breaking your existing environment or project file.

Here are my export settings.

I’ll try with the newest version. I didn’t notice that mine was so old.

Are you aware that YouTube recently added a dark theme?

For your source video, can you please open one, view Properties and report the value of the Format field in the Video tab.

Also, do you have GPU Effects enabled in Settings?

Yes, I heard about the dark theme… But I don’t want to make two versions of each video, so I will focus on the white theme for now, and if there is a massive adoption of the dark theme, I will think about changing the design of my videos in the future.

The format is yuv420p. Full parameters below.

I don’t see GPU effects… Perhaps due to the old version I use.
I will download the new one soon.


Does the contrast reduction still occur to your video if you do not add the white PNG? Here is an experiment you could try:

  1. Make a copy of your project.
  2. Remove the PNG from the project that adds the white border
  3. Export the video
  4. See if the contrast is still reduced.

I just try the new version, (18.08.14) with the same mlt… same result.
As for this demo I just put two images one over the other (to have quick render), I will fuse the two images in Gimp, and just render the video, without the second layer.
I’ll post the result.
I do this because it is difficult to detect the contrast bug in the video, it is more visible on the white bands.

I have the same problem, just rendering an image with a white zone.
The white zone appears as light gray after processing.

I made some tests and have not reproduced it (white is 254,254,254 but not gray). Here is an image saved from MPC-HC for me:

I even made a test with v17.09 and checked in VLC 3.0.3 without having the problem.

Damn, I don’t understand why i’m wrong…

Yeah, strange, here is my test after uploading to YouTube

So it’s white in the capture, but gray in youtube… You experience the same in youtube… Strange.
Do you have a special config in MPC-HC ? I think I have a “from scratch” one, but I’ll try to download it again to verify.
Possible problem of coding of information ? I heard about scale 0-255 or 16-235 or something like that. Could be the reason ?

No, my YouTube video shows a white border. You have to wait for the player UI to hide - move the mouse outside the player area.

For me, with YouTube…
Background is white with Firefox.
Background is gray with Google Chrome.
I use both side by side.
Not sure why it’s different per browser.

Umm… nvm, it just changed back to white on Chrome.

Would you be willing to share your image and .mlt file so that others can try to reproduce your problem with the exact same media?

So, seems to be different depending on the browsers…
I tried with the three I have on my PC. My favorite is Firefox… That’s why I saw the problem, which seems not appear in Chrome on my PC.

Here are the three captions (yes, I’m no longer a beginner, I can post more than one picture :slight_smile: )

Firefox Quantum 61.0.2

Edge 42.17134.1.0

Chrome 68.0.3440.106

All on Win10, 1803, 17134.228