How to create GIF (which looks more natural) with dithering from video frames or Array of UIImages?

Question

Here is the link (https://imgplay.zendesk.com/hc/en-us/articles/360029411991-What-is-GIF-Dithering-Option-) where it says When you save the file as GIF with dithering, it can make your GIF more natural.

How to implement Dithering for creating more natural GIF from UIImages or video frames using Objective-C or Swift?

Answer 1

Assuming your source image is 8-bit per channel RGB, you could use vImage. vImage doesn't have a vImageConvert_RGB88toIndexed8, but you can split your interleaved image into three 8-bit planar buffers for RGB. I don't know exactly how well this would work, but you could convert two of the three channels to Indexed2 with vImageConvert_Planar8toIndexed2 and the other channel to Indexed4 with vImageConvert_Planar8toIndexed4. That would give you the required 8-bit lookup table.

Apple have loads of Accelerate sample code projects here. Optimising Image-Processing Performance discusses converting interleaved images to planar format. If you have a known palette, Applying Color Transforms to Images with a Multidimensional Lookup Table may be a solution to quantising your image to 256 colors.