VNC optimized to almost 30% bandwidth raw (40% zlib)

Const Kaplinsky const "at" ce.cctpu.edu.ru
Tue, 29 Aug 2000 10:23:04 +0000


>>>>> "RDV" == Rudi De Vos <Rudi.De.Vos "at" netbuilding.simac.be> writes:

RDV> Test:

RDV> Internet explorer running "http://services.simac.be/vnc" Java
RDV> applet with moving text. Vncserver bind to internet explorer
RDV> (single application) Let client and server run for 3 min. no
RDV> keyboard, mouse movement. I know this is no represent test for
RDV> all vnc applications, But the difference between raw data is
RDV> immense. Perhaps there something wrong whith the buildin
RDV> statistics for zlib ? Supposing the compressed data is send on
RDV> the network this gives a drop in traffic. Tomorrow I try it with
RDV> a sniffer.

RDV> rawSize=3200 compSize=62 totalRaw=2211664 totalComp=71970

RDV> rawSize=4096 compSize=24 totalRaw=5027240 totalComp=115091

Hm, so where did you get 30%? It's 56% raw, 37% zlib. :-)
Zlib percentage is smaller.

I've took a look at zlib encoder sources in WinVNC once more, and zlib
statistics are actually inaccurate. First, the code does not count
small rectangles sent raw by zlib encoder. And it does not count 4
bytes sent within each rectangle containing compressed data lenght.

And I've looked at the applet at http://services.simac.be/vnc. I think
it does not represent or even come close to any real VNC session.

-- 
With Best Wishes,
Constantin
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