Mozjpeg-渐进式jpeg图像渲染，首先显示灰度图像

Question

I am using the following command to generate progressive JPEGs using mozjpeg (cjpeg utility)

cjpeg -quality 85 -outfile outputfile.jpg inputfile.jpg

On rendering this output image, a grayscale image is first shown which is then followed by a greenish image and then the original image. After quite a bit of study, i found that splitting of DC coefficients is done to reduce the size of image. But, i need the rendering to be a blurred to bright one. How to achieve this?

Answer 1

There's an option for this:

-dc-scan-opt   DC scan optimization mode
             - 0 One scan for all components
             - 1 One scan per component (default)
             - 2 Optimize between one scan for all components and one scan for 1st component
                 plus one scan for remaining components

The default causes grayscale look, because it sends luma separately from chroma.