Answers.Body: <p>Seems like <a href="http://cinelerra.org/docs/split_manual_en/cinelerra_cv_manual_en_14.html#Difference-key" rel="nofollow">Cinelerra can</a>. Haven't checked how well it works though, I've been wanting to install it for quite some time but never got around to doing it yet.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2012-06-30T22:22:35.570Z
Answers.Text: You don't have to _convert_ your computer, it's no problem to install a Linux parallel to Windows (assuming that's what you're using now). Do it, it's worth the effort! — Cinelerra might even run under Windows with Cygwin, though getting that to work tends to be rather difficult. — I don't mind if you don't accept this answer, but you should add something about the operating system to the question body, especially since you write "[free software](http://www.gnu.org/philosophy/free-sw.html)" there, which at least to me suggests a _preference_ for Linux.
Answers.UserDisplayName: leftaroundabout
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Answers.CreationDate: 2012-07-01T00:18:09.990Z
Answers.Text: Ah, sorry about not mentioning the OS. I am on windows (7). And the converting my computer was somewhat of a joke. :D
Answers.UserDisplayName: SuperFilman
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Answers.UserDisplayName: leftaroundabout
Answers.Body: <p>Check the blend modes of your video tracks. Almost any actual editing and compositing software, has blend modes for "Difference". So i'm nearly sure, you don't need a separate software. </p>
  
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Answers.CreationDate: 2012-07-02T16:19:12.930Z
Answers.Text: Yes, but that's not the same thing. Difference blending just combines two images, while difference matte uses one image to create a mask for another one through which it can then be combined with a third image.
Answers.UserDisplayName: leftaroundabout
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Answers.Text: Sure, but create your difference-blend node (assuming a node-based compositor), feed it into a keyer, and there you are, a difference keyer.
Answers.UserDisplayName: Charles Duffy
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Answers.LastEditDate: 2012-07-02T15:19:28.030Z
Answers.UserDisplayName: DoktorHauser
Answers.Body: <p><a href="http://blender.org" rel="nofollow noreferrer">Blender</a>, which is <strong>free and open-source</strong>, can do difference matte keying.</p>
  
  <p>I don't know if it's better or worse than After Effects' keyer because I haven't used it before.</p>
  
  <p><img src="https://i.sstatic.net/FDTv8.png" alt="Difference matte keying with Blender&#39;s node-based compositor."></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2012-07-04T17:00:24.677Z
Answers.Text: Thanks. I've used Blender alot, but never thought about that. Your's is my favorite answer so far.
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Answers.UserDisplayName: PtrFdr
Body: <p>I would like to know if anyone out there knows of any free software, or software not as expensive as Adobe After Effects, that can do <a href="http://help.adobe.com/en_US/aftereffects/cs/using/WS3878526689cb91655866c1103a9d3c597-7b52a.html#WS3878526689cb91655866c1103a9d3c597-7b4ba" rel="nofollow">Difference Matte Keying</a>? I have searched the web a little and have not come up with any promising results. <strong>Note: Chroma Keying is not an option. I am on a Windows 7 computer.</strong></p>
  
  <p>Thank you in advance for your time, and possible help.</p>
  
Tags: <video><software><effects><composing><freeware>
Title: Difference Matte Keying software
UserDisplayName: SuperFilman
ThreadText: # Difference Matte Keying software
  
  (Asked by: username_0 on 2012-06-27)
  
  I would like to know if anyone out there knows of any free software, or software not as expensive as Adobe After Effects, that can do [Difference Matte Keying](http://help.adobe.com/en_US/aftereffects/cs/using/WS3878526689cb91655866c1103a9d3c597-7b52a.html#WS3878526689cb91655866c1103a9d3c597-7b4ba)? I have searched the web a little and have not come up with any promising results. **Note: Chroma Keying is not an option. I am on a Windows 7 computer.**
  
  Thank you in advance for your time, and possible help.
  
  **Tags:** video, software, effects, composing, freeware
  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_4 on 2012-07-03. Score: 4 | Accepted answer
  
  [Blender](http://blender.org), which is **free and open-source**, can do difference matte keying.
  
  I don't know if it's better or worse than After Effects' keyer because I haven't used it before.
  
  ![Difference matte keying with Blender's node-based compositor.](https://i.sstatic.net/FDTv8.png)
  
  > **Comments:**
  > **username_0**: Thanks. I've used Blender alot, but never thought about that. Your's is my favorite answer so far.  
  
  ---
  
  ### Answer by username_1 on 2012-06-30. Score: 1
  
  Seems like [Cinelerra can](http://cinelerra.org/docs/split_manual_en/cinelerra_cv_manual_en_14.html#Difference-key). Haven't checked how well it works though, I've been wanting to install it for quite some time but never got around to doing it yet.
  
  > **Comments:**
  > **username_1**: You don't have to _convert_ your computer, it's no problem to install a Linux parallel to Windows (assuming that's what you're using now). Do it, it's worth the effort! — Cinelerra might even run under Windows with Cygwin, though getting that to work tends to be rather difficult. — I don't mind if you don't accept this answer, but you should add something about the operating system to the question body, especially since you write "[free software](http://www.gnu.org/philosophy/free-sw.html)" there, which at least to me suggests a _preference_ for Linux.  
  > **username_0**: Ah, sorry about not mentioning the OS. I am on windows (7). And the converting my computer was somewhat of a joke. :D  
  
  ---
  
  ### Answer by username_2 on 2012-07-02. Score: 0
  
  Check the blend modes of your video tracks. Almost any actual editing and compositing software, has blend modes for "Difference". So i'm nearly sure, you don't need a separate software.
  
  > **Comments:**
  > **username_1**: Yes, but that's not the same thing. Difference blending just combines two images, while difference matte uses one image to create a mask for another one through which it can then be combined with a third image.  
  > **username_3**: Sure, but create your difference-blend node (assuming a node-based compositor), feed it into a keyer, and there you are, a difference keyer.  
  
  ---
  
  