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Re: [Qemu-devel] Sensible VNC encodings
From: |
Johannes Schindelin |
Subject: |
Re: [Qemu-devel] Sensible VNC encodings |
Date: |
Wed, 21 May 2008 14:14:11 +0100 (BST) |
User-agent: |
Alpine 1.00 (DEB 882 2007-12-20) |
Hi,
On Wed, 21 May 2008, Anthony Liguori wrote:
> Johannes Schindelin wrote:
>
> > On Tue, 20 May 2008, Anthony Liguori wrote:
> >
> > Clearly, you have never waited one minute for a full screen update
> > from a machine half around the planet.
> >
> > That is what happens here with hextile + an compressed SSH tunnel,
> > just in case you thought this was pure speculation.
> >
> > It is pretty obvious why, too: generic compression, such as SSH's,
> > will never outperform specialized compression, such as tight
> > compression.
>
> Tight uses zlib compression in combination with a palette mechanism.
> Hextile is a palette mechanism so adding zlib compression to it (via
> ssh) makes it pretty comparable to Tight.
I'm awfully short on time, so this is only a hint to the explanation:
Tight compression can fall back to a Jpeg scheme which is lossy. You
obviously did not know that, and obviously this is what I have to use to
make VNC usable.
Hth,
Dscho
Re: [Qemu-devel] Sensible VNC encodings, Alexander Graf, 2008/05/21