Legacy ImageMagick Discussions Archive

I found this link: 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)."

I do not know. The best reference I know is http://www.imagemagick.org/Usage/formats/#jpg_write Yes, I already looked at it. In -sampling-factor option, it talks about the block size in addition to chroma sampling. However, I'm not able to relate them. I tried finding about it a lot and my best ...

Any idea on what block size (8x8 or 16x16 ??) is used in JPEG compression by ImageMagick? And, is there a way to change this default block size?