ImageMagick JPEG compression block size

Question

Does anyone know what processing block size (8x8 or 16x16 ??) is used in JPEG compression by ImageMagick? And, is there a way to change this default block size?

Answer 1

Please refer en.wikipedia.org/wiki/JPEG. It says "After subsampling, each channel must be split into 8×8 blocks. Depending on chroma subsampling, this yields (Minimum Coded Unit) MCU blocks of size 8×8 (4:4:4 – no subsampling), 16×8 (4:2:2), or most commonly 16×16 (4:2:0).