AVIF (AV1 Image File Format) is a modern image codec that has gained widespread adoption due to its high compression rate and support from a wide range of applications. One aspect of AVIF that contributes to its efficiency is its support for different types of chroma subsampling.
Chroma subsampling is a technique used in image and video encoding to reduce the resolution of chroma information (color information) relative to luma information (brightness information). AVIF supports three types of chroma subsampling: 4:2:0, 4:2:2, and 4:4:4.
In the case of 4:2:0 subsampling, the resolution of the chroma information is reduced by a factor of 2 horizontally and vertically. This can be beneficial in cases where the loss caused by the subsampling is not apparent to the human eye, as the human eye is more sensitive to changes in luminance than to changes in color.
On the other hand, 4:2:2 and 4:4:4 subsampling methods retain more chroma resolution, which may be necessary in cases where color accuracy is a priority, such as in graphic design or professional photography.
When it comes to choosing the right chroma subsampling method for a specific use case, it's important to consider the intended use of the images, the target audience, and the available processing power. For example, someone creating images for the web may prioritize a smaller file size and choose a 4:2:0 subsampling method, while a graphic designer working on a print project may prioritize color accuracy and choose a 4:2:2 or 4:4:4 subsampling method.
Overall, AVIF's support for different chroma subsampling methods is a valuable feature that contributes to its efficiency and versatility as a codec.