Built-in iSight will not work with Skype

Question

I have a new Macbook Pro that I purchased about a month ago, running OS
X 10.5.8.
I've been using Skype to video chat, and at first everything was working
very well. In the middle of a chat, however, the video stopped working
altogether.
If I go to the video tab in Skype preferences, the camera will then turn
on and I can see myself, but once I go back to the call, the camera
won't turn on (the green light on my camera stays off too). In video
preferences I have the following options checked: Enable Skype Video,
Automatically receive video from: People in my Contact list, and Show
that I have video to: People in my contact list. I have also tried to
enable the "Start my video automatically" option but to no avail. The
video camera it is set to use is the Built-in iSight.
I have tried reinstalling skype, including deleting all the preference
files on the computer, but that did not help.
The video works fine in other applications such as Photobooth, iMovie and Google Chat. I have browsed through the many Skype forum posts about similar issues, as well as Apple forums and have tried every fix that people have suggested including resetting my SMC, updating all my applications, trying Skype under different user accounts, reinstalling Quicktime, reinstalling Skype (as outlined in the Uninstall guide for mac), repairing permissions, etc.
I am pretty sure that this problem began directly after I switched to
SCREEN SHARING during a video chat. When I switched back to Video, it
did not work.
No other applications that use my camera are running.
I am assuming that since it originally worked with Skype, and since I had not touched ANY of the options in Skype and have done nothing other than try screen sharing, and since I did a complete Skype reinstall includeing preferences, that the problem should NOT be with the Skype program itself, but rather something that was modified in the operating system configuration during screen sharing.
The only other thing I can think of trying is to reinstall iSight, although I haven't been able to figure out how to do that, or to reinstall my entire operating system, which I don't see as an acceptable solution.
I am using Skype Version 2.8.0.659
Any help getting this fixed would be greatly appreciated.
I have posted a similar topic in the Skype forums along with a screen shot of my Skype preferences window: http://forum.skype.com/index.php?showtopic=422861
From my online reading in both the Apple and Skype forums, it seems as though this is a relatively common problem. If I can find a solution from either Skype or Apple, I will post the solution in both of the forums.
Update: I just upgraded my OS to 10.6.1 and my camera started working again. Then, I was in a chat and I lost my internet connection. As soon as I got back online I restarted the conversation and the camera doesn't work again. This is getting to be ridiculous.
Thank you for your time,
rystheguy

Answer 1

Hi,
It is years since I tried Skype. (Probably in Tiger)
I use Little Snitch, a utility that can report the ports and IPS any App is trying to contact.
For Video chats it seems the Skype process spreads the load across many "Servers" wanting to connect to about 3 doz (I got fed up with clicking the accept Button)
For this reason I do not think it is very secure.
I only today read a post that said Skype had Screen Sharing.
iChat 5 makes it clear (well if you run /Applications/iChat.app/Contents/MacOS/iChat -errorLogLevel 7 In Terminal) that there is a "camera" setting for the Desktop which may be a forthcoming thing or is about produce the Screen Sharing pic. (i.e iChat lists two "cameras" in the log produced by the above Terminal command).
iChat 4 and 5 use the Apple Remote Desktop engine to do Screen Share as does the Screen Sharing App invoked from the Finders Go Menu > Go to Server and using VNC:// as the Link type.
I would have no idea what protocol Skype are using.
They created their own Video protocols and similar with SIP (Session Initiation Protocol) for Connecting to POTS (Plain Old Telephone Systems) Phones in disregard for Internationally agreed Standards.
I doubt that it makes use of the ARD engine. It will probably be a reinvention of the wheel again.
I took a look around the Skype web site but could not find any mention of how they are doing Screen Sharing.
I would guess it is similar to the iUSBCam method of Desktop as Video Feed.
Do the Console or System Log in Console (Applications/Utilities) have any messages about this ?
9:59 PM Monday; September 21, 2009