Answers.Body: <p>What you're looking for is a difference matte. (Not to be confused with a Color Difference Key which is similar to regular chroma key.) It can certainly be done, though you should know that difference mattes are fairly temperamental.</p>
  
  <p>The way it works is by finding the difference between an image and each frame of video, and removing anything that's the same, while leaving whatever's different. This means you need a locked-down camera when filming and you need a clean plate of the scene without any actors (or whatever you're trying to remove).</p>
  
  <p>I'm not knowledgable in Blender, so I don't know if it's possible there. I haven't used one in a long time, so don't know what the current landscape is for plug-ins or apps that do this.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2014-10-05T23:00:57.577Z
Answers.LastActivityDate: 2014-10-05T23:00:57.577Z
Answers.UserDisplayName: user1118321
Body: <p>Is there a simple way to make the background of an video transparent, removing the background where it is similar to the image? 
  Just like a green screen, except that the chroma key is an image.</p>
  
  <p>Is this possible in blender, or some other free/cheap mac programs? </p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2014-10-05T01:06:57.257Z
Comments.Text: I don't have time for a detailed map, but look at difference blends, the problem would be that for video, noise may well be a problem, but you might be able to tweak it to work.
Comments.UserDisplayName: AJ Henderson
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2014-10-05T13:59:14.113Z
Comments.Text: photobooth does it, so it's possible.  but I don't know anything that'd let you export video off the top of my head
Comments.UserDisplayName: Jason Conrad
Tags: <video><video-recording><greenscreen><chromakey><blender>
Title: Transparent video background from image
UserDisplayName: Jørgen
ThreadText: # Transparent video background from image
  
  (Asked by: username_0 on 2014-10-04)
  
  Is there a simple way to make the background of an video transparent, removing the background where it is similar to the image?
  Just like a green screen, except that the chroma key is an image.
  
  Is this possible in blender, or some other free/cheap mac programs?
  
  **Tags:** video, video-recording, greenscreen, chromakey, blender
  
  > **Comments:**
  > **username_1**: I don't have time for a detailed map, but look at difference blends, the problem would be that for video, noise may well be a problem, but you might be able to tweak it to work.  
  > **username_2**: photobooth does it, so it's possible.  but I don't know anything that'd let you export video off the top of my head  
  
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  ## 1 answers
  
  ### Answer by username_3 on 2014-10-05. Score: 1
  
  What you're looking for is a difference matte. (Not to be confused with a Color Difference Key which is similar to regular chroma key.) It can certainly be done, though you should know that difference mattes are fairly temperamental.
  
  The way it works is by finding the difference between an image and each frame of video, and removing anything that's the same, while leaving whatever's different. This means you need a locked-down camera when filming and you need a clean plate of the scene without any actors (or whatever you're trying to remove).
  
  I'm not knowledgable in Blender, so I don't know if it's possible there. I haven't used one in a long time, so don't know what the current landscape is for plug-ins or apps that do this.
  
  
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