Log in here to report bugs or suggest features. Please enter your phone number in the international format and we will send a confirmation message to your account via Telegram.
We've just sent you a message.
Please confirm access via Telegram
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.
- Disable HDR when recording a video with the native iOS Camera app.
- Send the video as file.
The video is sent compressed but the color balance is not correct. The entire video looks too green.
The video is sent with correct colors and looks the same as the original.
iPhone 12 Pro // iOS 14.2
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.