IChat audio not working during video chats

Question

For the last month or so I have been unable to get normal audio connections during iChat video chats.
The person on the other end can hear me, but the audio I hear from them pops in and out and frequently seems muted. I thought it was their computer at first, but now the problem seems to be happening to me chatting with different people that are on different computers. It's also not an internet problem at my home, because the problem occurs consistently when I am at different locations, in different cities.
It's not my mute button, and I've checked my sound preferences in system preferences and everything looks okay. This seems to be associated with a system software upgrade and I'd love to know how to fix it. Running OS 10.6.4 on a MacBook Pro 17".
I read some of the other discussions on this topic and couldn't find a solution, or anything I could easily understand how to fix.
Thanks for any help!

Answer 1

Hi,
iChat 5 uses your whole Internet speed.
This is different to iChat 4 and Earlier that was capped by what was set in System Preferences > Quicktime > Streaming (Also not there in Snow Leopard).
If you and your Buddy are on vastly different Internet speed iChat will try to match the lowest Upload speed at both end.
After that Buffering tries to smooth out the natural variances in Connection speed you have.
This is where the issue mostly lies.
iChat has always tended to drop Audio before any picture issue show up.
As the Max setting in Quicktime was 1.5Mbps a 5% or even 10% variance was handled by iChat.
However in iChat 5 you may be on a 20Mbs+ service both Up and down and 5% of this is more than can be handled by the iChat Buffering.
What you can do is Limit iChat in the iChat Menu > Preferences > Video/Audio section > Bandwidth Limit.
Set it to 500kbps as a start.
Get your Buddy to do the same no matter what version they have.
If this is successful then try the 1Mb setting.
You can change during a chat.
If you have the Connection Doctor Open (Video Menu) you can watch the Bit rates change as the Buffering smooths this out.
Get you Buddy to Increase his Bandwidth Limit once the Bit rate has smoothed out.
Essentially repeat for each increase until you find what speed you can manage predictably and works with the most amount of Buddies.
NOTES:
Don't try below 200kbps. The real world lower Limit is 100kbps and you need some for any variances if someone only has 128kbps upload.
384Kbps is the lower limit for a 4 way Video chat with you as Host, so 500kbps is more than enough. You will only see figures in the Connection Doctor above this if both ends are on a very fast service. (Higher speeds as Host does stop 3rd and 4th Buddies causing a quality drop off).
Things that can impinge on your Connection Speed are other computers such as one doing a Download of something. You are left with a smaller Portion (Bandwidth).
Other apps also use some Bandwidth which is why iChat refers to the control as Bandwidth Limit - allowing enough for other apps.
11:44 PM Saturday; September 11, 2010
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