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<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Hello I have noticed a problem with vic on our
machines here in the </span></font><font size=2 face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial'>UK</span></font><font size=2
face=Arial><span lang=EN-GB style='font-size:10.0pt;font-family:Arial'>. The
problem is manifested in two ways.</span></font></p>
<ol start=1 type=1>
<li class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>The GUI for the vic window on the video machine
is unresponsive, i.e. it is difficult to access GUI buttons, etc and the
window often doesn’t redraw correctly.</span></font></li>
<li class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>On the display machine video windows which have
been expanded remove themselves periodically. You can also notice that
there has been some re-ordering of the transmitted windows within the vic
application.</span></font></li>
</ol>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>It is as if the transmission is stopped and
re-started. There are no join or leave requests on the network during this
time.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>With some experimentation I found that altering the frame
rate that you are transmitting changes this behaviour quite dramatically.
Changing the frame rate below 25fps results in a responsive GUI on the video
machine and the windows the displayed video streams remain stable. Indeed
moving the frame rate up to 30 fps produces a similar fix, though the GUI is
slightly hesitant in responding. Note that with a PAL signal connected the
actual transmitted frame rate cannot achieve greater than 25 fps.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>I also noted that if there is no signal connected
then the displayed streams are not interrupted. I also noted that this has
little to do with the data rates involved as, there is little difference from
sending black and burst signals to sending an ‘off-air’ TV signal
resulting in data rate of approximately 1.5Mbps.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>In have repeated this on 2 different AG rooms and
both behave identically, though tests with the PIG on a windows XP machine using
a web cam were not able to demonstrate this effect.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>A quick fix is to set the 4 transmissions to 24 fps,
but I wonder if anyone else is suffering from the same problems or has any insights.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>This obviously will only affect those using PAL
sources, though it may be interesting for someone with an NTSC or indeed SECAM
source to comment when running at 25fps.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Steven</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Steven Jack</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Videoconferencing Manager</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>University of Glasgow</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Computing Service</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Glasgow G12 8QQ</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>UK</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Tel +44(0)1413303828 Fax +44(0)1413303820</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Email: </span></font><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>s.jack@compserv.gla.ac.uk</span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span lang=EN-GB
style='font-size:12.0pt'> </span></font></p>
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