Chroma key is a special effects/post production technique for composting (layering) two images of video streams together based on color hues or Chroma range; e.g. it can used to remove backgrounds from photo or videos. It is also known as green screening.
What is a Green Screen?
A green screen is simply a big green screen. It is excellent for effects because most video editing software can easily separate the green screen from whatever is standing in front of it, and overlay the screen with aliens, burning ships, or whatever your imagination can come up with and now this technology can be utilized at home. It is possible to purchase one from most photo stores but it’s cheaper to simply buy a hideous green gabardine fabric from your local fabric store and some PVC pipes and A-clamps from your local hardware store.
How to make a portable green screen on a small budget
If you would like to make your own portable green screen, please check out the following directions
• 4 yds. Of Green gabardine fabric: can be found a local fabric store) the wider the better (buy two panels if one isn’t enough). . Try to get it as wide as possible to avoid seams. However, if you have seams, they can be keyed out. If you don’t have a sewing machine, try A-clamps or use
• 10 ft. long PVC pipe (local hardware store)
• 2 stands e.g. mic stands or lighting stands (Craigslist or EBay).
• Weights (optional)
• Flexible mic clips
1. Sew a pocket or seam on top of the fabric to slide the PVC through. Do it across the entire length of the fabric. You don’t have to sew this pocket if you don’t want, you can use safety pins if you wish.
2. Slide fabric on PVC pipe.
3. Place both mic stands on either side of the PVC pipe. Extend the arms vertically the lock them down, nice and tight. You may want to but some weights at the base of the stands for extra support.
4. Gently force the PVC pipe into the mic clips on both stands.
5. Take mic stands all the way up and lock them into place. Use the A clamps to help stretch the fabric for a tight, even green screen.
6. Now you are ready to shoot.
• Your green screen can be lit with three Lowell 250W lights; One Lowell light coming from up and behind in order to create separation, one as key on camera left, shot through a white silk umbrella ( You can use a white bounce card for fill), and the last Lowell shot through another umbrella on camera right to light it evenly
• To get the cleanest key: Separate yourself from the fabric. Use a backlight to your hair, skin, and clothes a distinct, easy to separate color from the ugly green color you are using.
How to use green screen with a webcam
There are many ways to utilize your green screen with your webcam. Here are some tips to help you get started:
- Run your preferred web cam and video editing program and switch to the device tab, put the checkmark near the web camera section to open it, find your device in the drop down list. You can also use other devices as a source of web camera footage like a real time video of your desktop, a static image, or predefined video files.
- Switch to the effects tab and activate the green screening section. Specify the color you want to replace the background image. Pick it from the preview window the pick button or let the program detect it automatically
- Select an image or video that will represent the new background of your camera picture. Supported image formats include, TIFF, BMP, JPEG, PNG. Supported video formats: MPEG, MOV, AVI, MP4, FLV, MKV, WMV
In addition, it is important to note that the tolerance option specifies the threshold of the color value e.g. the higher the number the more variance of the Chroma key color the program will allow. Also, the noise option allows you to take into account and compensate noise in the source footage caused by compression artifacts, and other reasons.
Using Your Green Screen and Webcam to Stream from Twitch.tv.
Twitch.tv is an unexploited facet of video game culture; many don’t know that video games have become their own form of passive entertainment. Therefore to capitalize on this data, Twitch is a service that lets gamers stream their video game play for others to watch online from gaming platforms like PlayStation, Xbox, PCs, and mobile devices. In addition, this service includes social functions, like chat. in addition to a library of recorded gameplay. Video games have become their own form of passive entertainment.
If you want to stream from Twitch.tv, it can be an overwhelming thought. However, it is much easier than you think. Here are some tips to help you get started:
- You will need a twitch.tv account. This is required. Make sure you choose a good username because it is the first thing people will know about you and sets the theme for your channel
- Have a 3MB upload minimal; this is ideal for streamers who use 1800-2500 bitrate
- You will need broadcasting software to be able to send your game capture to Twitch.tv so that others can see it; two most popular software options are X-split and OBS.
- A microphone is recommended to help bring a certain flavor to your channel.
- Before you start planning, it is a great idea to determine what you are going to do with your channel? What type of games will you play, what time of the day will you stream? How many days a week? Would you like to make it a career or just stream casually for friends? Etc.
- Social media accounts are very useful for streamers because they allow you to connect with your viewers, and other streamers. This is a Very important part of streaming and will help you Network with other casters because they can help bring exposure to your stream. Social media can also be sued to let your viewers when and what you are streaming, or if you have to cancel or delay your cast.