Chroma Key Live (v09-11-03)
Novemeber 11 2009, by ZLP
IMPORTANT!!! ---- Check for updates: http://www.zachpoff.com
Summary:
Chroma Key Live is a FREE realtime HD-capable green-screen solution (or free realtime chroma key software if you want to get technical). It generates a live key on your computer screen while you shoot with an attached camera. I didn't want to buy Veescope, Wirecast, Visual Communicator, or BoinxTV, so I made my own solution. Version 09-11-03 has been completely redesigned with GPU acceleration and HD support.
In the days of analog video...
the camera's live signal was routed through a keyer in the control room and delivered back to an on-set monitor. This way, the production team could see exactly how the actor looked when composited over the background image. Of course, you needed an expensive studio or at least a video mixer.
Then came the DV era...
and editing software brought chroma keying to the masses, sort of. How do you plan a shot when all you see is an actor against a big green wall?
Now it's simple again...
Run the firewire output from your camera into a laptop running Chroma Key Live. Click on your background and it will disappear, revealing the movie or still image of your choice. Switch to full-screen and call "action!"
Chroma Key Live gives you control over key tolerance and edge fade, and offers features like full-screen mode, image-flip (so your actors don't see themselves backwards), and a useful "transport" so you can control the playback of your background videos. SD and HD formats are supported and there are keyboard shortcuts for all important functions.
Supported Cameras:
• Apple iSight, built-in or attached via FireWire
• no manual exposure
• "UVC compliant" webcams, the majority of USB cameras
• no manual exposure
• IIDC cameras, mostly expensive "machine-vision cameras"
• DV cameras with a firewire port (NTSC or PAL)
• HDV cameras - Only if it can send a standard definition DV signal over its firewire port while shooting HDV!
• The image on the Chroma Key Live screen will be standard definition, sorry.
• Panasonic HVX200 and HPX170 DVCProHD cameras
• You need to have Final Cut Pro installed to use these cameras, otherwise Chroma Key Live cannot see them
• The following recording formats are NOT supported: 1080/24PA, 720p/30PN, 720p/24PN, 480i/24PA
• HD capture cards from Blackmagic, etc.
Connecting Your Camera:
Connect your camera to your computer and open Chroma Key Live. Open the "Video Input Settings" window and choose your camera from the device list.
Note that the list shows all the devices your system supports, even if they are not attached! For example, everyone with Final Cut will see DVCPROHD devices, even if they don't own a compatible camera.
Choose a capture resolution that matches the format of your camera. The video window will change to match the resolution you select. If the window is larger than your monitor, choose the "half" or "quarter" window-size options on the main screen.
Background File Preparation:
Chroma Key Live will scale your background image to match the current video dimensions. It's best to prepare your backgrounds to match these dimensions. Later in your post-production software you will be able to load your backgrounds and achieve a familiar spatial match between your actors and your backgrounds, with no arbitrary scaling.
Like most editing software, the Chroma Key Live transport uses the J,K and L keys for backwards, pause, and forwards. You can also hit the spacebar anytime to play your video clip from the beginning. This is useful for cues where the actor needs to hit a mark on the background movie.
Preferences:
All settings are saved automatically to an xml preferences file whenever you close Chroma Key Live. If you want to get really nerdy, you can edit the xml with any text editor (but Chroma Key Live doesn't monitor changes in the xml while it's running).
GPL License:
Chroma Key Live is Copyright 2008, 2009 by Zach Poff. It is Free Software, released under a GPL 3.0 license. You are free to copy it, modify it, and redistribute your changes provided that all derivative products remain GPL licensed. The source files are included in the download. (See http://www.gnu.org/licenses/gpl-faq.html for details about this license.)
There is a caveat: MultiScreener was developed in the (non-free) MAX5 visual programming environment ( http://www.cycling74.com ) which is required if you want to edit the source code. The MultiScreener application contains the MAX5 "Runtime" environment, which is not GPL, so my license pertains to my contributions only.
(Former versions were distributed under a Creative Commons by-nc-sa license, which was a little too vague and restrictive with respect to commercial use of the software. The GPL provides more freedom to use the software commercially.)
Change Log:
Version 09-11-03 (Nov 11, 2009)
Changed to GPL 3.0 license
Fixed: In fullscreen mode, aspect ratio of video is preserved
Fixed: In fullscreen mode, menu bar is no longer displayed
Fixed: Video input menu redesigned and clarified
Added: GPU-accelerated, so frame-rate is much faster even at HD resolutions
Added: HD support
Added: background filename is now shown in main window
Removed: Title Safe / Action Safe Guides because it's a pain to calculate them for each new resolution
Version 08-12-16 (Dec 16, 2008)
First Release