21–30 of 88 posts
Earlier quoted context omitted.
http://acid2.acidtests.org/ ?
Oh, ironically, this old test breaks on Google Chrome 90.0.4430.212 on macOS.
Colors that can be stimulated using a single wavelength are spectral colors, which are only a small subset of perceptible colors. In the CIE xy model, spectral colors are on the curved boundary, while the straight boundary is the line of purples - impossible colors.
Edit: And because CIE XYZ is used as a sort of universal connecting and definition space, all our color spaces are defined in terms of it. But this leads to a the-map-is-not-the-territory fallacy: CIE XYZ was based on just a handful of observations and generously extrapolating. CIE XYZ does not define the set of visible colors. It's a map of colors.
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This post is about conversion from the video's color space to a rendering color space, and the problems with that. Another fun question is whether that rendering color space is actually the display device's color space, or nah. While browser do output color management (i.e. they use the color profile of the output device and convert all their output to the ad-hoc color space that represents), I don't think they do that for video actually. In fact, there are virtually no video players supporting color management on the output side of things.
> If you are using ffmpeg and you don't have color flags set, you are doing it wrong.
This.
Set the color tag in your files. Please.
I don't get the image at the top. Why are they showing a different color in the two left most squares?
It's an image from one of the examples showing the situation. Specifically, this is how Firefox renders the different videos. > There is a lot to unpack here. Since 709.mp4 and 709vui.mp4 look the same, we can deduce Firefox assumes BT.709 when the VUI is not present. 601vui.mp4 rendering correctly means the VUI is honored for BT.601 content. However, when a BT.601 file without a VUI is rendered as 709 it becomes ver…
Earlier quoted context omitted.
It's an image from one of the examples showing the situation. Specifically, this is how Firefox renders the different videos. > There is a lot to unpack here. Since 709.mp4 and 709vui.mp4 look the same, we can deduce Firefox assumes BT.709 when the VUI is not present. 601vui.mp4 rendering correctly means the VUI is honored for BT.601 content. However, when a BT.601 file without a VUI is rendered as 709 it becomes ver…
Its labeled with a different color value tho (0, 77, 0). Is it just saying that's the value it is rendering as, but implying that it was encoded as the same green color?
> And many people know that specific colors are really just wavelengths in the electromagnetic spectrum. Colors that can be stimulated using a single wavelength are spectral colors, which are only a small subset of perceptible colors. In the CIE xy model, spectral colors are on the curved boundary, while the straight boundary is the line of purples - impossible colors. Edit: And because CIE XYZ is used as a sort of u…
I would hope that similar frameworks on Windows and Linux distributions are too.
The Mozilla JPEG encoder mozjpeg assumes a high density digital display and encodes for that, typically with less banding but softer.
Not a lot of people cared for mozjpeg and the barely perceptible differences, even though file sizes were smaller into the deal.
This experience made me aware of how few people are working at the cutting edge of image processing, for images or video. It is amazing how much we take their work for granted.
Frustrating differences may be between screens, browsers and operating systems, we are lucky to have what we have got and also lucky to have such forgiving eyes. The whole shebang is nothing short of a miracle.
(Mux founder here, but adding some additional community bits to the conversation) Probably unsurprisingly, the (honestly absurd world of) color is a pretty consistent topic among video engineers. Color theory is one of those areas that people working directly with it see it as a completely unsolved problem, and everyone else largely takes it for granted. This is a small sample size, but these are all talks just from…
I was told search for "perfect" parity across users was in vain because perception of colour varied too much, from blood sugar level to physiology and etc. What is the true benefit of going after this on software side? I mean I am not understanding the difference it causes on artistic statement or emotional impact.
I understand and support "true colour" across all hard/software but is it really that impactful?
Screens also display colours differently. Trying to get the perfect colour is futile in the same way trying to get pixel perfect web designs is.
First thing I do when buying a new TV/monitor is search the internet for others calibration efforts (usually avforums). It's amazing what even basic calibration like this can do to improve image quality (unassisted by professional tools).