high compress Image

Question

Hello, I'm trying to do a "remote desktop viewer". For this I need to send the user's desktop - and it's alot of infomation for sockets...(especially if the resolution is high and the information can approach to 5.3MB (1680X1050))

So I started to compress with GZIP stream and the 5.3MB became 500KB, then I added my own compress algorithm (I think it called RLE) - taking near pixels and write it in format that 1) have 256 >> 3 = 32 colors(for red,blue,green each) and write how many pixels in a row have the same color. + GZIP.

That brought the compression to be in average 60~65KB - up to 200KB and it can be also under 5000 if the screen is totally white.

Now - I thought (and haven't implemented yet) about passing the difference between each frame - for each line I write where the difference(between the pixels) is starting and how long is the difference. well, it can help - maybe I could get 30KB for each frame in average. but for sockets it's alot.

has anyone ever succeed to fit with this problem? (and how of course...)

Answer 1

You may wish to review the source code of a VNC.

Most VNC servers implement several different forms of compression.

Answer 2

There are standard algorithms for compressing images: e.g. JPEG.

A further optimization is to know something about the image: for example on a desktop, items like the Windows Start button, and various application icons, and widgets on the title bar, are standard: so instead of sending their pixels values, you can send their logical identifiers.

Yes people have succeeded with this problem: people who write remote desktop software, including the open source VNC.