Ok,
At iChat Launch it checks the hardware available and Internet speed.
This is used to set what size pic you send to your Buddy.
An Intel running 10.5.8 and iChat 4 is likely to aim for a pic 640 X 480 pixels.
This is reduced if the Internet speed it can see is lower.
iChat "Reads" the Quicktime Streaming setting which as Automatic is read as 384kbps
(This is in response to an issue with Tiger and iChat 3 that saw that setting as zero kbps)
This is independent of the Actual speed you get.
If you set 1.5Mbps in the Quicktime setting iChat will work up to that speed with the proviso that your Upload speed is at least that fast.
Most peoples Internet speed is lower on the upload although some Cable services are symmetric (Same Up and Down).
Therefore the Upload speed, if lower than the Quicktime setting, becomes the deciding/controlling factor.
The Connection Doctor tells you if the Frame rate has also dropped from the 30fps max.
What it does not show is the Pic size it is using
It will slow the frame rate to maintain the pic size. (15 as mine shows is realistically the lower limit - anything less than 10 lacks proper movement).
640 X 480 is 0.3 megapixels per frame
iChat can adjust this size downward in an effort to maintain Framerate.
So iChat takes all these factors and settings and tries to pitch the connection and framerate to give you the biggest view it can.
During the connection it makes a another Bandwidth Check (see the lower part of the Full Log you posted) and this is used as the final figure.
Once the final figure is set then the Connection is made and the Buffering in iChat takes up the variances in the internet speed at both ends.
This Buffering attempts to smooth out frame Rate changes that are required when the Bitrate in the Connection Doctor varies too much.
It is at this point in very fast Internet services that the speed at one end can be a problem for the other.
A 5% variance on a connection speed of only 500kbps is minimal (only 25kbps )
A 5% of 10Mbps is a lot more (in round terms that whole 500kbps from above).
Now your Full log mentions 2229kbps This could be a 111.45kbps variance using that imaginary 5% figure.
If your service does vary by that much it may be enough to get iChat at the other end to give up as the Buffering can't cope.
You may see your Frame rate figure start to change frequently. (this would means cast changes in the data the Buddy gets to try and Buffer).
That is why we suggest Changing the Quicktime setting to 1.5Mbps (it is as fast as most Video Streaming sites)
If there are further issues then limit iChat's Bandwidth to 500kbps.
This will lower what iChat uses and cap it beneath the figure that might be involved in any variance in speed and eliminate the need to Buffer at the other end.
Of course if watching the Connecting Doctor show both ends varying a lot in Bitrate an Framerate then you both may be experiencing variances and doubling any effect they have (it can be worse if you are on the same service).
Looked at another way iChat is like a really smart car that can judge road conditions and other factors and then it tries to set Cruise Control.
It obviously does this thinking the fuel will come in a steady stream.
When it comes in fits and starts they will be problems and the journey will not be smooth.
Now that is a lot to digest and it is late here.
Will catch up tomorrow.
11:31 PM Saturday; April 30, 2011
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb( 10.6.7)
, Mac OS X (10.6.7),
"Limit the Logs to the Bits above Binary Images." No, Seriously
