By Prince McLean

Published: 10:00 AM EST

Leopard's iChat AV 4.0

In Mac OS X Leopard, Apple added a variety things that might not be commonly associated with instant messaging, including document sharing and screen sharing. Why relate screen sharing with online chat? The magic answer is presence indication, the idea AOL promoted and developed around the Buddy List. Presence indication finds users online and reports their availability.

This makes iChat's Buddy List an ideal way to discover users across the Internet who have an AOL or GoogleTalk/Jabber account, but may have a dynamic IP address that makes them problematic to address directly. With AOL's OSCAR or open Jabber servers keeping track of where users are and whether they are busy or not, iChat provides an ideal context for setting up screen sharing.

Along with the remote presence indication provided by AOL or Jabber networks, iChat has also long provided another discovery protocol: Apple's own Bonjour, formerly known as Rendezvous. While AOL and Jabber track users across the Internet, Bonjour tracks users on the local network, without requiring any servers to manage things.

Bonjour uses the same automatic discovery technology as AppleTalk, which was released back in the mid 80s with the original Macintosh. Combining long distance AOL/Jabber with local Bonjour discovery means iChat provides a variety of ways to find other users you might want to share your screen with or set up in a conference. Bonjour even works when the Internet--and remote servers--are unavailable.



Document Sharing

The new iChat AV 4.0 in Leopard provides two options for document sharing (portrayed above, on Apple's website). When you drag a file into a chat with a user who can support a video chat, two drag targets are presented: one for uploading the document via file transfer, and the second for document sharing. The latter option works like a video conferencing system's document camera.

Any file that can be viewed with Quick Look can be "beamed" with document sharing. While the document is being shared, the sender sees it in a Quick Look panel view, while the viewer on the other end sees the document as a video chat. The sender can scroll through the document, leading the recipient through the file at a set pace, although there are no collaborative white-boarding features for drawing on the document. The person on the receiving end has a read-only view, so they can't mouse around in the document themselves.

Document sharing works well for photos and graphical presentations, but isn't ideal for text documents, which are hard to see in the video-like presentation. Those kinds of documents can be simply forwarded as direct file transfers using the other drop target. Applications can tie into Quick Look to provide specialized views; Keynote and iPhoto presentations and can be played with animated transitions for example.



Screen Sharing

The other entirely new feature in iChat is screen sharing (above, the new icon in the bottom of the Buddy List), which relies upon the open source VNC software. Apple earlier built the VNC server into Tiger, which can be enabled and used either by standalone clients like Chicken of the VNC, or by administrators using Apple's Remote Desktop package.

There hasn't been a really simple and obvious way for users to set up a screen sharing session however. In the new iChat, it's effortless. Click the new screen sharing icon in iChat for any user that can support the feature, and it drops down two options: share my screen or request to share theirs. Once the user on the other end approves the connection, a VNC session is setup.

The user viewing the remote screen gets their own desktop put into a "picture in picture" window. Clicking on that window swaps the remote desktop with their own, and closing the window terminates the session. The performance of screen sharing is related to the quality of the connection; it is very usable over a local WiFi network.

This feature will make it much more bearable to do long distance troubleshooting for remote users, where seeing and doing is much easier than trying to explain what's happening. Who would have thought to build screen sharing into an instant messaging client?

Text Chat Features

The new iChat AV 4.0 (below) also adds features for text chatting. The new interface drops the old brushed metal look to present a standard Loepard window with tabbed chats that appear in a sidebar. It also natively supports GoogleTalk accounts, making it easier to set one up without having to know anything about Google's server settings.

While earlier versions of iChat have long supported sending SMS messages--the real work is done by AOL's OSCAR servers--the new version presents an easy to use interface for typing in numbers. The new iChat also supports invisibility and manages file transfers in a downloads window similar to Safari.



Video Conferencing Features

Apple's iChat offers one of the best and easiest to use video conferring system anywhere, even including professional systems that cost thousands of dollars. While the idea of consumer video phones were touted in "2001: a Space Odyssey" back in the 60s, and were pitched to users since the 70s by Bell Labs, consumers never really jumped on them. The biggest problem with video conferencing is that people are often too self conscious about how they look and what's going on behind them.

Picking up the phone or sending an IM doesn't involve the fear of being immediately judged based on your appearance. To skirt around this problem, Apple expanded iChat to use its video conferencing features to perform document sharing, which takes the focus off the user and puts it on photos or a document. Two other new features in iChat that distract from the awkwardness of staring into the unblinking eye of the camera are backdrops and video effects.



Backdrops (above) replace your background using a trick from H.264 video compression. Unlike the regular pictures displayed by film, compressed video commonly only updates the screen in areas where it has changed. When you set up a photo or movie to replace your background, iChat asks you to step out of the frame, and captures what your background looks like. When you step back in, it masks around the part of the camera's image that has changed (you), and draws your selected photo or movie in place of the static background behind you. This works best if you have a well lit room, and obviously requires that your background isn't moving.

If you're more worried about your own appearance than your messy bookshelf behind you, you can also select one of the effects from Photo Booth, either to comically distort your image with mirrors and distortions, or to use one of the art filters to present yourself with some distracting blur, pixelation, or color effects.

It is also interesting to note that iChat has always presented a view to the user that is a mirror image, while sending a regular image to the remote user. The reason for this is that most of us are more used to seeing ourselves in a mirror than in video or photographs. Seeing an image of ourselves that isn't a mirrored reflection can be as uncomfortable as hearing a recording of our own voice. I didn't notice this until I compared iChat with Yahoo's video chat, which doesn't do this. The result is that iChat presents the user with a more familiar and flattering self image, which is a bit of a relief when throwing oneself on camera.

In addition to the simple background swap, iChat can perform any video trickery Quartz Composer can think up. Apple demonstrated a hologram filter that presents your image as translucent and flickering -- like R2D2's Obi Wan recording -- among others. Savvy graphics users will be able to create a variety of plugin filters.

Doing the work of processing video in real time requires a recent Mac with a decently powerful video card, but it does not place any negative processing burden on the recipient. Some filters may even make it easier to compress the video, providing a better video quality over slower connections.

Some of the most interesting new features in Leopard's iChat may come from third party Quartz Composer compositions. All told, that makes iChat a compelling reason in itself for upgrading to Leopard.

Check out earlier installments of AppleInsider's ongoing Road to Leopard Series: Mail 3.0, Time Machine; Spaces, Dock 1.6, Finder 10.5, Dictionary 2.0, and Preview 4.0.