In the AV industry we pride ourselves on providing the best-quality audio and visual communication to our clients. One way in which we can do that is to offer video solutions in 4:4:4 color.
When digital video was first introduced, video files sizes were large in relation to storage and transmission capabilities. One of the ways to address these larger file sizes was to introduce “chroma sub sampling.” In digital video there are two main components; Luminance and Chrominance. Luminance (or contrast) is the difference between the lightest and darkest parts of an image. Chrominance is the color saturation of an image. The human eye is very sensitive to small changes in contrast (Luminance) and is less sensitive to changes in color saturation (Chrominance).
To make digital video files more manageable, compression was introduced. A true-color video signal (4:4:4) includes all of the red, green, and blue color information of each pixel. In a 24-bit system, there are 8 pixels for each color and thus 24 bits in true color. Chroma subsampling reduces file size by removing color. In the AV world, the most common color space is 4:2:0, which is DVD quality. However, with 4:2:0 quality, the viewer is only seeing 50% of the available color. To make up for that loss of color, the pixels that were removed are recreated by borrowing or “interpolating” from the adjacent pixels. In some instances 4:2:0 quality is perfectly acceptable. In other instances however the chroma sub sampling provides the viewer an experience that is less than optimal.
I can think of at least three instances in which 4:4:4 color is required:
- Telemedicine: Surgical procedures streamed over a network require extremely accurate color information on the receiving end.
- Spreadsheets: Small text on a spreadsheet in color is virtually unreadable at anything other than 4:4:4 quality.
- Corporate Branding: Accurate color representation in a company logo. Think of how some iconic brands might appear if the colors were not accurate represented.
If two video streams with identical content are placed next to each other, one at 720P 4:4:4 color and the other at 1080P 4:2:0, chances are extremely high that the average viewer will choose the lower resolution image with the true color as the more impactful. Color trumps resolution pretty much every time. So the next time you are specifying a streaming solution make sure to factor in which color space is most appropriate for the application.
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View the blog post in it’s original form here: http://www.clearone.com/blog/what-is-444-color-and-why-should-i-care/