-1
I have two images. The first is before undergoing lossy compression:
Picture #1:
The second is after undergoing lossy compression:
Can anyone explain to me what is going on here? How does this compression scheme work?
Sacha T Red
Posted 2015-06-05T16:35:30.260
Reputation: 251
2
The common term for that is "color banding". It results from rounding off similar colors together when you reduce bit depth.
As an analogy - imagine drawing a rainbow using a box of 100 crayons, and then trying to draw the same thing with a box of 12... you lose imagine the loss in smoothness and discrete colors that would result.
For more reading, also see the related terms Color Quantization and Posterization.
BowlesCR
Posted 2015-06-05T16:35:30.260
Reputation: 2 607
1
It looks like a 24-bit colour depth image reduced to 8-bit (256 colours), which is the colour depth used by the GIF format.
paradroid
Posted 2015-06-05T16:35:30.260
Reputation: 20 970
3This looks very much like a massive reduction in color space - palette anyone? – Eugen Rieck – 2015-06-05T16:41:31.537
2Can you give us more context? Or is this some sort of homework assignment? (The latter wouldn't be bad per se, but we'd like to know) – slhck – 2015-06-05T16:41:58.533
1Its called 'dithering', and involves reducing the number of colors, and aliasing the pixels of a given color so that the full 3 byte color is only stored once. – Frank Thomas – 2015-06-05T16:47:52.710
This is what happens in TeamViewer if you disable UDP and set your firewall so that the other person has to forward all the bandwidth through one of their servers. – Sacha T Red – 2015-06-05T19:26:35.350
I thought that this was the result of H.264 compression. – Sacha T Red – 2015-06-05T19:30:01.533