On 18-6-2010 15:21, Seak, Teng-Fong wrote:
> On Thu, Jun 17, 2010 at 10:20, Corne Beerse<cbeerse@gmail.com> wrote:
>> On 15-6-2010 17:59, Seak, Teng-Fong wrote:
>>> It seems that VNC response depends on screen response, ie VGA
>>> card's speed. I think VNC only sends screen updates to client only
>>> after corresponding pixels are changed on screen (ie in VGA memory).
>>> Am I correct?
>>>
>> This is only true for the native msWindows server side implementation:
>> There the vnc-server (the remote side) just grabs the contents of the
>> screen-memory and forwards that. Hence, the screen update of the session
>> can never be faster/better than the hardware. It's even worse: depending
>> on the way the screen-memory is grabbed, the screen update can be realy
>> slow.
> Is real VNC for Windows such "native ms windows server side
> implementation"? And is it possible to know in which way the
> screen-memory is grabbed?
See the vnc server properties, tab 'capture method':
- Poll for changes to the desktop: just frequently scans the video
memory for changes and sends that as updates to the viewers
- use vnc hooks to trace changes: vnc-server hooks into the display
driver and sends updates as the happen. This might slow down for systems
that do verry fast updates.
- I'm not sure, but I think the 'poll console windows for updates' is
for full screen applications.
- I donnot know what 'alpha blended windows' are so I donnot know what
this option does.
>> To make it even worse: the hardware accelerated video display stuff does
>> not use the memory for the screen, it inserts the picture 'on the fly'.
>> Hence where the real display shows the movie, the vnc-session shows a
>> black square.
> I'm not interested in movie related problem, so this doesn't
> concern me, correct?
It's not only movies, it includes every application that does direct
display updates. I'm not sure but I think even a lot of direct-x
applications are involved here.
>> There are however vnc-server installations that are linked more to the
>> display-driver and might do a better job on some side.
> Essentially the same question as above: I'm using real VNC for
> windows, so how could I know if the server installations are linked to
> the display driver or not?
For example, see the option 'Use VNC hooks to track changes' in the vnc
server capture methods properties. That is the kind of link I mean.
>>> I've got a PC whose VGA card is "ATI 3D RAGE IIC PCI". On the
>>> screen, the response is quite good. But when used in VNC, the
>>> response is horrible -- very slow.
>>>
>>> Is there any plan to improve this part? Eg using threads if
>>> that's not used already.
>>>
>> Try to find a vnc-server that is tailored to your display hardware.
> How?
Twiggle with the capture options.
On top of that, there are several splits from the origional vnc.
RealVNC, TrueVNC, TightVNC and UltraVNC are ones that come to mind.
>> On the other hand, using the current installation, twiggle a little with
>> the way the screen is updated/captured/refreshed.
> I'm already using "Use VNC hooks to track changes". Should I
> disable it? But that would mean I have to switch to "Poll for changes
> to the desktop". Isn't this a worse option?
It sound strange but disabling this setting can speed up things. I had
an application that did a complete window update more than once per
second. Switching back to the default polling gave me a workable solution.
_______________________________________________
VNC-List mailing list
VNC-List@realvnc.com
To remove yourself from the list visit:
http://www.realvnc.com/mailman/listinfo/vnc-list