iChat in Lion compatible with PC AIM?

You can exchange text with AIM users, but I think the audio and video codex and connection protocol used by iChat is different from what AIM uses.

You could try Skype which will work with just about any platform.

Hi,

In Theory... the Answer is that iChat and AIM are supposed to be compatible for Video and Audio Chats as well as Text Chats.

It is only supposed to be Screen Sharing and iChat Theatre stuff that AIM will not do.

iChat, since iChat 4 has used the same port for Audio and Video data both In an Out (iChat 3 and earlier used four separate ports).

It has never been entirely clear how many the AIM on PC app uses. (It would seem to be one).

Part of the iChat Connection Process involves negotiation over the ports to be used.

One the whole this seems to work despite iChat using one from 16393-16402 and the AIM app using something from 1024-5000.

Having said that it does seem to work better if your router can do UPnP and you have it Enabled.

Most other issues are then based around how fast the internet Connection is at each end and how much data each computer can shove out (processor based stuff)

This would appear to be where you are at.

Try going to iChat Menu > Preferences> Video Section

Set the Bandwidth limit to 500kbps

This is fast enough for iChat to do 4 way chats with other iChat users but may reduce the bandwidth iChat uses which in turn reduces the data sent - which in turn may mean the other end can process their own video and Audio to be able to send it.

At the iChat end the Video is Buffered.

Realistically this is still at the iChat 4 level where the OS setting in System Preferences > Quicktime > Streaming also limit iChat to a max throughput of 1.5Mbps

Modern Internet speed can be greatly in excess of this.

Capping the Bandwidth limit does two things.

Smooths out any Issue with the ISP varying the Internet speed (can effect both ends)

As mentioned it can allow smaller data amounts to be sent so one end is not overwhelming the other.

The Buffering will drop frames to try and keep the Video Smooth.

At some points the Audio will get dropped as it cannot remain in Sync.

There used to be adjustments back in AIM 5.9 to the Video quality at the PC end.

Lower quality leads to less pixels per frame allowing the processor to produce more frames and therefore smoother video.

This, or any other form adjustment does not appear in the AIM app any longer and there does not appear to be much they can do.

One thing they can do is turn Off "Real Time"

This is like the Bonjour Account option to Send Text as your Type.

For some reason it is not compatible with iChat and effect Video and Audio chats as well.

This Users Tip was written some time Ago in trying to cover many of the version that were then in use (AIM 5.5 and 5.9 were still common and post AIM 5.9 version (A sort of watershed version) had only got to version 6.5

There maybe some things in there that I have forgotten.

Skype will do this.

However when you download Skype and look in it's Preferences it will list a Port it would like to use for Video and Audio

However if this is not open it will use "Fall Back" ports such as common mail or even the Web Browsing port - meaning that you do not really know how it is getting through your Firewall or router.

I use Little Snitch to check what IPs and ports and App is using.

9:56 PM Monday; January 9, 2012

Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"

 iMac 2.5Ghz 5i 2011 (Lion 10.7.2)
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb (Snow Leopard 10.6.8)
 Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images."  No, Seriously

Message was edited by: Ralph Johns (UK)