Stepok Screen Codec v2, the second generation screen codec of us, is a special designed codec for recording and compression screen.

Why need compression?

If we just save screen changes as its original data, a 1 minute’s video could be, let’s take 1024 by 768 true-colors as sample:

1024 x 768 x 3(RGB) x 60(s) x 2(frames/sec) = 283115520B = 276480KB = 270MB

A normal 160GB hard-drive can only save only 9 hours video. And it will take about 30 minutes to send 1 minute’s video through 512K ADSL link.

Now you can see how important the compression is. A good compression will get smaller file size, and that means less space on storing and less time on sharing. Time is money, so it is worth to find a better compression way.

For office style screen, SSCV2 cam get only 100-400K output per minutes, compression ratio over 600:1 , for webpage style with many photos and animations, SSCV2 can get 2-4M per minutes, ratio over 70:1.

What is the common way to compress screen video of other software?

General screen recording software and remote controlling software has their own way to compress screen, based on LZW. Normally it has 3 steps:

• Step 1: Low down color depth from 24 bit color to 16 bit even 8bit color.
• Step 2: Use lossless compression, normally LZW, to process I frame.
• Step 3: In P frame, do a simple comparison between this frame and last frame, then compress the changed area.

Some of them use standard MPEG serials codec to compress screen.

Neither LZW way nor MPEG is the best solution for a composed video like screen. The LZW way may have good compression ratio on text and icons, but bad performance on photos. In contrary, MPEG serials have better performance on photos but poor compression ration on text and icons.

We need a special one, which is SSCV2.

Compare to others, how is the performance of SSCv2?

Quality comparation:

Compression Ratio:

Compare to remote desktop protocal (RDP)

Although RDP is not a compression algorithm, running with same conception, we can still compare it with SSCV2 on how efficient they transfer/record screen. For RDP, we note the receive bytes when running a remote desktop; at same time, record it with SSVC2 with same quality. Then, compare the file size and the received bytes.

The testing result is out of our expection. SSCV2 have 0-30% smaller output than RDP!

In theory, RDP, based on transferring primitive drawing command, could be much more efficient than transferring compressed, rendered images/surface such as SSCV2 do. But the testing result shows NOT.