Color Space Bug?

Bug
1

What is your operating system?
Windows 10 64-bit

What is your Shotcut version (see Help > About Shotcut)?
24.01.28

Can you repeat the problem? If so, what are the steps?
Not sure of weather this a bug or not, but still figured I’d ask about it. When converting videos from my iPhone, the convert to bt.709 Color Space box is checked. However, the converted videos look no different than the original. Before they would, so I really don’t know what’s going on. Any help would be greatly appreciated and thanks for reading this far.

2

I was going to post a very similar bug report.

What video codec are you converting it to that you noticed the color change?

I noticed it with the “Best” option that produces a Ut Video file.

3

“videos from iPhone” hear means Dolby Vision HLG HDR videos. I reproduced it. This was a regression in version 23.09 I fixed for the next version. FYI, technically, HLG videos are intended to be truncated when displayed in SDR, which is what Shotcut does without conversion. However, what was done when the Rec 709 checkbox is checked is a some generic tone-mapping, which can be desirable but not always.

1 Like
4

I’m using the H.264/AC-3.MP4 option.

5

Thanks for responding and apologies in advance for any confusion. Are you saying that the color change that Shotcut did before was not suppose to happen even with the box checked? If that’s the case, I guess this isn’t a bug like I thought it was?

6

It was a bug for all quality options. I just added information to say that sometimes you might not want to convert with the Rec 709 option.

7

So, is what’s going on now not a bug? Also, I tried not selecting the box but the same thing happens, no color change unlike with the previous versions (but only with the box selected).

Sorry if I sound confusing, I actually liked the color changing as it made the videos look a lot more like the ones shown on my iPhone. The colors in the same videos downloaded from iCloud look different for some reason (but just the ones taken with the iPhone 13).

8

You reported a real bug that first appeared in version 23.09. It is fixed for the next version.

9

Oh, so are the colors suppose to look like they do on the iPhone screen after the conversion if the Convert to bt.709 Color Space box is checked? The box is checked by default whenever I go to convert videos from my iPhone 13. If this is the case, then I’m glad that this’ll be fixed in the next version.

10

They will not look the same as on your iPhone whether you convert with the fix or not because they are HDR and Shotcut does not support HDR. Converting them with the color change is only an approximation in SDR. (high vs standard dynamic range)

11

Oh ok, well as long as it does that again it should be fine.

12

I don’t want to create a new topic since my problem is also related to colors.
This was tested on versions 24.01.28 and on the new nightly build from github 24.02.15

I see a difference in colors when GPU effects are enabled, these are imported frames from the same video where GPU effects are enabled and where they are disabled.
This is what the image looks like when GPU effects are turned off (the image has the correct colors):

CPU
CPU1920×1080 169 KB

This is what the image looks like if you enable GPU effects:

GPU
GPU1920×1080 188 KB

These are the parameters of the video file (recorded using OBS):
prop

13

I’m having the same issue in Linux with GPU effects enabled. Exported frames look washed out.

14

Do not hijack a bug thread to report on a related issue. Resolved bugs are not monitored much. We do search filters on bug posts that have the accepted tag and not solved to look for things to do.

With that said, this GPU Effects color bug is fixed for version 24.02. This was a preview bug, and File > Export Frame is based on the preview. It is not in the beta; you will need to get the daily build from 24.02.21+ before release.