Good Day,
I have created my own DCT calculation arrays. Therefore for 256 * 256 pixels size of image, I have prepared 1024 blocks of DCT arrays (8 * 8). How do I use jpeg_write_coefficients to write my arrays values into jpeg file using jpeg_write_coefficients. 
jpeg_write_coefficients needs jvirt_barray_ptr * coef_arrays. How do I create this?