Quality Loss of JPG/JPEG Compression

Q

Where in a picture the quality is lost the most when using JPG/JPEG compression?

✍: FYIcenter.com

A

Quality loss happens most near areas with sharp contrasts between adjacent pixels. Areas with smooth variations of tone and color will have the least quality loss.

Because of this fact, JPG/JPEG is best file format for phtographs and paintings and it is the most common file format used by digial cameras.

On the other hand, JPG/JPEG is not well suited for line drawings and other textual or iconic graphics. Such images may be better saved in a lossless format such as GIF or PNG.

The following image shows the quality loss of JPEG compression with a quality setting of 50%. Darker areas represent bigger quality losses. Note that quality losses are concentrated near sharp edges and having a block-like shape.
JPEG Quality Loss at 50%

2013-11-01, 2926🔥, 0💬