> --- On Fri, 11/7/08, Dan <[EMAIL PROTECTED]> wrote:
> > From: Dan <[EMAIL PROTECTED]>
> > Subject: Re: How much bandwidth is in use?
> > To: g3-5-list@googlegroups.com
> > Date: Friday, November 7, 2008, 10:34 AM
> > At 9:58 AM -0800 11/7/2008, Jonas Lopez wrote:
> > > > I have just found a webcam with a good,
> big,
> > analogue clock face
> > >> with a second hand. Most of the time, you
> can see
> > it
> > >> hit on each of the 5 seconds in line, but
> some
> > times it skips 2 or so
> > >> in a 5 second block. I wonder if this is an
> > optical problem or are we
> > >> seeing 30 frames / second or 1 frame /
> second
> > ince sometimes it
> > >> misses 2 seconds?
> > >>
> > >> People don't want their open webcams to
> suck
> > up all their bandwidth,
> > >> so they often set the refresh rate to be
> very
> > slow. That
> > >> means watching something like a clock -
> unless
> > the refresh is
> > >> under 1/2 sec, you're going to miss
> > "ticks". Many webcams
> > >>refresh only once
> > > > every 10 or 30 seconds!
> > >
> > >This is my point: since I can see that the second
> hand
> > HAS hit on
> > >each second, except once in a while it misses a
> > seccond, does this
> > >tell us that they (the sender) is sending at a set
> rate
> > of 1/2, or
> > >1, or what per second. They could NOT be sending
> at a
> > refresh rate
> > >of once every 10 seconds, else we would see the
> second
> > hand of the
> > >clock jump to the new location and hold for the
> the
> > next frame.
> > >Using a simple analogue clock in the pix is very
> > instructive, I
> > >think. What do you think.
> >
> > Right. But figuring out where the rate is slowed is
> not
> > necessarily
> > so simple... (IOW, your conclusion is reasonable but
> not
> > 100%
> > definitive).
> >
> > There's the frame rate at which the actual webcam
> is
> > making images.
> >
> > There's the speed at which its server is pushing
> the
> > data to the
> > reflector or you (depends on which protocols are in
> use,
> > etc)
> >
> > Then there's the speed at which you can receive
> the
> > data, decode, and
> > display it...
> >
> > QuickTime automatically drops frames, on your
> computer, if
> > it can't
> > process them fast enough to maintain the time sync of
> the
> > video
> > "feed" (be it a webcam, normal streams, or
> even
> > something you're
> > playing locally).
> >
> > - Dan.
Yess you make a good point, but on the other hand, if we
see that the cclock is NOT missing any "seconds hits" does
this tell us all, ALL the parts are working
at least at 1 frame per second or faster to produce a
thruput of 1 frame per second?
This has been especcially instructive as a way to test the
entire thruput of a video system. It is like an electronic gage
you can put in the pix easily and then see what the entire
system is doing for you. I wish I had a way to do this
myself.
BTW: What if the face of the clock is optical vs.
inserted electronically and what about using digital verse
analogue, I like the physical hand moving, so it eliminates
questions of insertion and tells us EXACTLY what the optical
system is doing for the scene picture.
JML
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed Low End Mac's G3-5 List, a
group for those using G3, G4, and G5 desktop Macs - with a particular focus on
Power Macs.
The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette
guide is at http://www.lowendmac.com/lists/netiquette.shtml
To post to this group, send email to g3-5-list@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/g3-5-list?hl=en
Low End Mac RSS feed at feed://lowendmac.com/feed.xml
-~----------~----~----~----~------~----~------~--~---
