If a video is recorded from an iOS device with HDR enabled, when sending it to Telegram as a compressed video, the color balance is not correct, resulting in a greenish tint all over the video.
For instance, video "1" is recorded with HDR disabled and sent compressed via Telegram. Colors looks natural.
Video "2" is recorded with HDR enabled, and when the video is sent compressed via Telegram, it looks more green than it should be and the color balance is not correct.
Workaround
Disable HDR when recording a video with the native iOS Camera app.
Send the video as file.
Steps to reproduce
Record a video from the iOS camera with HDR enabled.
Send the video from the attachment menu on Telegram and enable compression.
Current result
The video is sent compressed but the color balance is not correct. The entire video looks too green.
Expected result
The video is sent with correct colors and looks the same as the original.
I don't have an iOS device, but I do have some knowledge a bout color accuracy in videos. There are basically two things that can cause this sort of thing:
1. The colorspace tags are being stripped from the video, causing it to be displayed in the wrong colorspace. Non-HDR colorspaces are understandably the default. 2. When displaying the video, no colorspace conversion is performed to display it correctly.
Since we can clearly see a difference in colors from just the thumbnail of the two samples you uploaded, I'm assuming the former is what's happening and the colorspace metadata is getting stripped from the files.
This leads me to suspect another similar bug that is much more subtle: video files that are encoded as bt709 or bt601 are likely having that data stripped as well, causing their colors to be interpreted as one or the other (depending on device and sometimes even the video resolution). This can cause reds to be slightly more orange, or slightly more magenta, than they should be (depending on which standard it's encoded as, and which standard it's decoded as).
R
Richard Rosner
I don't think it's a bug in the normal sense, just the lack of ability to send anything but standard H.264 and maybe h.265 as compressed video. Nothing else. Since HDR videos are no special format, it just converts it to 720p h.264 and ignores anything special. So basically the fix for that "bug" would be to implement something like ffmpeg to handle pretty much any type of media.
Status changed to Fixed
D
Deleted Account
😚
M
Manul Ramzay
It's still the same old bug that never has been fixed. I have iPhone 13 pro max.
₳₦ĐⱤɆ₳ Ⱬ.
same from android, the problem is HDR/10bits and telegram still lacks support for this. Issue is still NOT FIXED, please telegram add support for modern formats.
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1. The colorspace tags are being stripped from the video, causing it to be displayed in the wrong colorspace. Non-HDR colorspaces are understandably the default.
2. When displaying the video, no colorspace conversion is performed to display it correctly.
Since we can clearly see a difference in colors from just the thumbnail of the two samples you uploaded, I'm assuming the former is what's happening and the colorspace metadata is getting stripped from the files.
This leads me to suspect another similar bug that is much more subtle: video files that are encoded as bt709 or bt601 are likely having that data stripped as well, causing their colors to be interpreted as one or the other (depending on device and sometimes even the video resolution). This can cause reds to be slightly more orange, or slightly more magenta, than they should be (depending on which standard it's encoded as, and which standard it's decoded as).
So basically the fix for that "bug" would be to implement something like ffmpeg to handle pretty much any type of media.