What is it?
ScreenPressor is a lossless video codec designed specifically for
screen capture. It provides unprecedented compression ratio
without losing a bit of information (quality is always 100%!).
It's probably the best technical solution for video tutorials and presentations.
Lossless
Most popular video codecs are lossy: they throw away information they
consider unimportant to achieve desired compression. This is acceptable
for movies but looks very bad with screen capture. Lossless codecs are
like ZIP files: they keep all original information. Here's a real example:
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Lossy compression (DivX, 970 kbps):
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Lossless compression (ScreenPressor, 312 kbps):
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Codec
A codec means compressor/decompressor and is not a standalone
application but a component used by other applications. After installing
ScreenPressor you won't see new icons on desktop or start menu but you'll
see it in the codecs list in all your video capture and editing apps.
To capture screen with ScreenPressor you may use Camtasia,
CamStudio (free),
HyperCam or other programs. Read more:
how to record screen in CamStudio,
using ScreenPressor in Camtasia.
If you already have some captured video you
can make its file size smaller by recompressing it without quality loss with
ScreenPressor using
VirtualDub (free).
How to recompress video.
Since version 1.1 there is a simple way to open codec settings directly:
just run "\Program Files\ScreenPressor\spconfig.exe"
Compression
We compared ScreenPressor with popular lossless screen capture codecs
as well as the most popular lossy codec (DivX, a MPEG4 implementation) on
several different video files.
The chart below shows file size in percent compared to TechSmith
Screen Capture Codec. I.e. TechSmith is taken as 100% and the lower
percentage the better compression.
Codecs involved in the test:
- CamStudio - CamStudio Lossless Codec v1.4 (LZO mode)
- DivX - famous MPEG4 implementation, DivX v6.8.2.
For most files (except gep)
maximum possible in single pass compression was selected. In case of
gep file bitrate was set to the same value as ScreenPressor, but
picture quality was very bad whereas ScreenPressor kept it lossless.
- Fox Magic - FM Screen Capture Codec v 1.00 (maximum compression
mode for screen capture)
- inno - inno Screen Capture Codec v1.20 (maximum compression mode),
also known as WinCAM Video Codec
- MSU SC - MSU Screen Capture Lossless Codec v1.2
- ScreenPressor - our codec
- TechSmith - TechSmith Screen Capture Codec v2.0.6 (maximum compression mode)
All codecs worked with the same key frame interval of 200 frames.
Files used in comparison:
- browsing.avi - 932x720, 24bpp, 820 frames (0:54),
2107 KB
A web browser scrolling couple of sites with text and graphics.
  
- excel.avi - 1016x765, 24bpp, 3000 frames (5:00),
1683 KB
Working on an Excel spreadsheet with added annotations.
  
- gep.avi - 1016x845, 24bpp, 2281 frames (2:32),
7537 KB
Using GraphEditPlus to build a youtube-to-avi converter in 2 minutes.
  
- printer.avi - 800x600, 16bpp, 1256 frames (2:05),
237 KB
Setting up a new printer in Windows 98.
  
As you may see, on a typical screen capture ScreenPressor shows the best
lossless compression. While lossy compression is known to be flexible in terms
of bitrate, it has lower bounds which in many cases for screen capture are
very high compared to lossless codecs such as ScreenPressor. In these cases
ScreenPressor provides not only higher quality but also better compression
than lossy methods like MPEG4.
Speed
The codecs were also tested for speed. Each codec decompressed video in its
own format and then compressed it back. The task was performed in VirtualDub
on a typical video (gep.avi). Next chart shows recompression speed in frames
per second on an Intel Core 2 Quad (Q8200) @ 2.33 GHz. Since it includes
both compression and decompression, the speed of compression only is approx.
twice higher.
This test shows ScreenPressor to be one of the fastest screen capture codecs.
Licensing
- For end users:
Decompression is free and limitless, anyone can download the codec and play
files created with it free of charge.
By default the codec works as unregistered version. In this mode it will
add watermark to video when compressing more than 3000 frames or longer
than 30 seconds. This allows you to test the codec and see if it fits your
needs. Decompression is fully functional in unregistered version and has
no limits. If you only need the codec to play video compressed with it, you
may do so free of charge and don't need to register. However if you want to
compress video without adding watermark you must register by purchasing
a license. After purchase you'll get your personal registration code which
must be entered in the codec to switch to registered version which doesn't
add watermark.
- For developers:
If you want to use the codec in your product or service such as screen
video recorder, VNC-like remote access application, video tutorial
producer etc., you may license ScreenPressor and enjoy its compression
power and speed. The codec is available as Windows VfW codec, Windows DLL,
or source
code for Windows and Linux (both 32 and 64 bit). Contact us for details.
History
Before ScreenPressor world leadership in screen captured video compression
held MSU Screen Capture Lossless Codec. Now it's obsolete and not supported
anymore. Its author Dmitry Popov, founder of Infognition Co. Ltd. previously
known as Dee Mon, is also the author of ScreenPressor.
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