What is Chroma key
Chroma key compositing is a special effects technique for compositing (layering) two images or video streams together based on color hues (Chroma range). The technique has been used heavily in many fields to remove a background from the subject of a photo or video – particularly in newscasting, motion picture, and videogame industries.
The ManyCam Chroma key feature allows you to remove your real background from the video stream and replace it with an image, video or any other supported ManyCam video source.
How to use the feature – Chroma key modes
Open the Chroma key tab and click on the On/Off button to enable the feature. You can choose between two modes – Color Picker and Auto, either of which may produce different outcomes depending on your environment, webcam parameters and settings, ManyCam video settings, and Advanced Chroma key settings selected.
The Auto mode
In the Auto mode, ManyCam automatically selects the colors to be replaced with the background, meaning you don’t have to do it manually. The result may vary, so it’s advised to adjust the Advanced Settings too in order to achieve the best outcome.
The Color Picker mode
Color picker allows you to manually select the colors that need to be replaced with a background.
Using the color picker control, choose the color you want to remove from your video stream. The best results can be achieved if you have a green background (or any other color that differs from your clothes, otherwise they will be removed from the video as well).
Selecting a background image
You can choose one of the predefined images as your background, upload your own custom background, or go with a transparent background.
Chroma key algorithms
HSL is an algorithm that allows you to adjust the hue, saturation and luminosity filtration. With HSL you can improve the quality by manually adjusting the Hue/Sat/Lum color components.
To select HSL, first enable the Advanced settings as shown below. If you selected the Color picker mode, proceed with keying out the unwanted colors with your mouse cursor.
Compared to HSL, the YUV algorithm works with solid-color backgrounds only, which are red, green and blue, therefore the result it produces may differ greatly from that of the HSL. Compared to HSL, YUV works better with the Auto mode, however, HSL offers a different color range to key out when used with color picker. Try both algorithms to determine which works best for you.
Fine-tuning the result
Use the settings listed below in order to eliminate color removal errors.
Blur contour allows feathering the bodyline edges to eliminate any artifacts, pixelation or ruggedness.
The Shrink contour function is responsible for reducing the object’s contour. To access this setting, enable Advanced Chroma key settings, and select HSL.
Color spills happen when light reflects from a shiny object that is present inside or maybe even outside the frame. During Chroma keying, color spilling mostly occurs from the Chroma key green screen backdrops. Spilled color casts a noticeable shadow on the subject, especially around the hair, shoulders, and bodyline.
The Spill suppression setting removes any color spill from the backdrop and ensures accurate color in the final image. To access this setting, enable Advanced Chroma key settings.
Smoothness adds an additional area to the image and then makes this area semi-transparent. Use this setting to eliminate artifacts along the edges of an object. This setting is also great for transparent objects made of glass or plastic.
To access this setting, enable Advanced Chroma key settings, and select YUV.
This feature currently is available in ManyCam Beta for macOS only. It allows you to blur your background environment leaving the focus on the person in the frame.
To run Background blur, make sure you met all of the following requirements:
- Metal hardware acceleration mode enabled. Navigate to ManyCam Settings -> General and select Metal from the list of Hardware Acceleration modes.
- Make sure you run macOS High Sierra (10.13.4) or newer,
- Make sure your hardware (GPU) is MPS-compatible. Such hardware includes macOS GPU family 1 or higher. For more information on Mac support for Metal, see Mac computers that support Metal.
To enable Background blur, navigate to the Chroma key tab and enable the feature as shown below.
How to use any video source as a background
Engage the Picture in Picture mode as shown in this guide.
On the background picture, select any video source such as a movie, YouTube video, your desktop or any other supported video source. On the foreground picture, select your webcam as your video source.
You should get something like this:
Enable Chroma key and proceed with removing the background color and adjusting the settings as described above. You should get something like this: