CamTwist is a program for Mac that lets you add special effects into your videos. It allows you to stream files, your desktop, photos and more. It's one of the best free programs for Mac to use with your broadcasting that there is out there.
The main CamTwist window is broken down into 3 parts. In the first part, you need to select a source of video, the second section is for video effects and the third allows you to fine tune your effects and create saved setups for later use.
- 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 Broadcaster will be compatible with the webcam source.
- 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
- 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.
- Flikr: Similar to Slide Show, the flickr set source will fetch pictures from a flickr feed and stream them on your broadcast.
- 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.
- 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.
Configuring Justin.tv with CamTwist
- If you had your browser running during the install of CamTwist, restart it first.
- If you have your CamTwist prefs set to not load the CamTwist driver unless the CamTwist application is running, you'll need to start CamTwist now.
- Start your broadcast.
- Select settings.
- Click the camera menu, and select CamTwist.
Audio with Sound Flower
As pointed out above, CamTwist doesn't do anything with audio as it relates to your broadcast. CamTwist interfaces to your video application as a video driver and has no knowledge of audio at all. Just as it's up to you to determine how to get audio from your mic into your broadcast, CamTwist is equally powerless to get audio from movie playback in your video application. The simplest way to get movie audio into your broadcast is to just let it play out of your speakers and let the microphone pick it up. For most people this technique is good enough but for everyone else there is Sound Flower
The basic idea behind soundflower is somewhat similar to the architecture of CamTwist. Soundflower comes with two parts. The first part is a driver and the second part is an application. The driver presents itself to MacOS as an alternative output device (like another set of speakers) and an alternative input device (like as if you installed another microphone).