CamTwist2.Documentation.Classic
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This documentation is still under construction
For version 2.0
CamTwist is a software package that lets you add special effects to your video chats. It's also possible to stream your desktop and still images. With CamTwist, you can also use multiple video chat programs at the same time. CamTwist Studio makes it easier to produce live broadcasts.
Installation
The easiest way to install CamTwist is to double click the installer package. The installer package will put CamTwist.component in /Library/QuickTime and the CamTwist application folder in /Applications. It is also possible to perform the installation manually. The only installation requirement is the QuickTime component bundle. The bundle can be placed in /Library/QuickTime or in ~/Library/QuickTime. The CamTwist application folder can be installed anywhere.
Configuration
CamTwist integrates with video applications by pretending to be a video camera. The basic idea in getting any particular video application to work with CamTwist is to find the configuration settings for the application and select CamTwist as the camera.
In some cases, the video application you're running may not allow you to select a particular camera. That could create some problems. One problem is that you may not be able to select CamTwist. Another problem is that you may not be able to select your real Camera. Until you installed CamTwist, you probably never had but 1 camera to choose, but now, with CamTwist installed, you could find yourself unable to use your camera in some applications without CamTwist already running. PhotoBooth is one such application.
The CamTwist preferences allow you to configure the behavior of the CamTwist video driver. The first pref, which is enabled by default on new installations, will prevent the CamTwist driver from loading unless the CamTwist application is already running. This is probably the best for most situations. What this boils down to is that without CamTwist running, it's as if CamTwist isn't installed. If you decide that you want to use CamTwist, simply run the CamTwist application first and then run your video application.
The second part of the prefs screen allows you fine grained control over when to use CamTwist. In my example, I've specified that I never want CamTwist to operate with PhotoBooth.
CamTwist Basics
The main CamTwist window is broken down into 3 parts. In the first part, you need to select a source of video. Traditionally you'd use a webcam but CamTwist allows you to stream movies, your desktop, photos and more.
Once you've selected a source of video, it immediately starts to stream. From there, you can add as many effects as you like and that your Mac can handle. After adding a video effect, you can adjust the effects settings, if any, in the third section of the window.
Video Sources
Webcam
Perhaps the most basic and traditional video source, the webcam source simply streams video from a webcam. Any camera that is compatible with QuickTime will be compatible with the webcam source.
Desktop / Desktop+
The desktop video source allows you to stream all or part of your desktop. By default, it will stream the entire desktop but you can deselect the Full Screen checkbox at which point a 320x240 section of your desktop will be selected. You can move the capture area around and resize it as needed. As a convenience, you can disable the Resizable Selection checkbox and the the capture area will then be fixed at 320x240 which is a 1:1 ratio with the broadcast and most optimal.
Desktop+ is very much like regular Desktop except that it is able to select individual windows and continue to stream their contents even if that window is covered by another application.
Slide Show
The slide show source allows you to stream still pictures. You can drag pictures to the list from your desktop and even iPhoto.
Movie
With the movie source, you can play movies over your broadcast. You can drag in several movies to the play list or select a single movie with the movie selection button. There are controls for playback, timeline, and for determining how the play list is treated.
Remember that CamTwist and CamTwist Studio are video applications only. When playing back a movie the audio will be output to the systems default audio output device, or another device as selected in the CamTwist preferences. For most people, this means that movie audio will output to your speakers. If you intend your audience to hear the movie audio, you can let it get picked up with your mic or you can use the more advanced technique of audio routing with Sound Flower (described below).
Flickr Set
Similar to Slide Show, the flickr set source will fetch pictures from a flickr feed and stream them on your broadcast.
Effects and Layers
You can add effect from the effects list and order them in any way that you like. The order of the effects is what determines how effects are layered.
Picture-in-Picture
Once you have your video going, it's possible to overlay another video source on your video. Simply select another video source and press the PIP button. The settings panel will show the settings for the other video source as well as the settings for PIP.
Chroma Key
Sometimes called a Green Screen, the Chroma Key setting in the PIP settings lets you subtract out any particular color on the overlay video. This is typically used to create the appearance that something is behind you, such as a picture or a movie. To make it work, you'll need to position yourself in front of a well lit, solid color wall and preferably a color that is not also on your clothes or too close to your skin tone. Once you're setup and you have the PIP going, select the chroma key check box and then select the chroma key color well. The easiest way to get the proper chroma key color is to show the preview window in CamTwist then use the magnifying glass feature of the color picker to select any part of your solid background. Once you done that, the background should disappear and you should appear to be in front of your other video source. You can use the Threshold setting in the PIP settings to make adjustments.
Saved Setups
After you've gone to the trouble of selecting and tweaking some effects, you can save the entire setup, or just part of it, for recall at a later date.
- Save selection only - This options allows you to select a subset of your effects to save.
- Don't include video source - As the name implies, selecting this option omits the video source from the saved setup. This makes sense most of the time for overlay type setups. That is, setups that contain text or graphics that you intend to show and remove.
User Menu
The User menu is a customizable menu that you can use to create shortcuts for frequently used operations. For every shortcut that you need, you create a menu item with the plus (+) button. Then use the popup menu to the right to assign an action to that menu. The available actions currently allow you to load setups, run AppleScripts and control CamTwist Studio. Optionally you can also assign a key sequence to that menu.
High Resolution
Starting with CamTwist 2.0, it is possible to work with resolutions greater than 320x240.
Flash-based streaming sites (ustream, stickam, mogulus, justin.tv, etc...)
If your end goal is to broadcast your stream to one of the popular flash based streaming sites, there are some signifiant hurdles that you'll need to jump.
- First and foremost, the flash broadcaster for some/all of the flash streaming sites are locked at 320x240.
- Some/all of the sites support high resolution with Flash Media Encoder (FME), but as of now there isn't any FME for MacOS X.
- The only current solution is to use a separate PC running FME with a video capture card that can capture the video from CamTwist (via the full screen option). More details on that setup are coming.
Quicktime Broadcaster
Quicktime Broadcaster (QTB) is similar to FME in function but not in compatibility. As of the time of this writing, the only streaming site that supports QTB is justin.tv (JTV). With QTB and JTV, you can stream in HD without any additional hardware. The JTV website has all of the details.
