mask section of video frames

Support Compositing and Post Processing
1

Hi All,
I am new to Blender and am slightly overpowered by it’s complexity on first sight…
I have been using Serif MoviePlus and am currently learning masking techniques in it.
I want to take a section of a video file showing someone’s head and dispense with everything else. Basically cutting it off their body then green screening away the background.
This is over 164 frames.
I’ve been reading up on masks within Blender but can’t get to grips with it.
Has anyone any pointers or links which would sort of bullet point me through it?

Regards,
Rob

2

As a simple example
Add your clip to the Movie Editor window
Change from Tracking to Mask.
Draw your mask
In the Compositor add a Image input node and select the movie clip
Add a Mask Node and select the mask you have created
Connect the mask to the composite Alpha node input.
You are now controlling the transparent areas of your output with the mask

Screen Shot 2015-09-08 at 17.47.17.jpg2300×1423 261 KB

You can track movement in your clip and make the mask move and change shape to mask out a moving part of the image

3

Hi Richard,
I gave it a whirl but the resultant animation showed the entire frames and not just the masked portion. I know it’s me - being very new to this amazing software.
Photo of what i did attached
Regards,
Rob

Attachments

blenderMaskAnim.jpg1920×1080 574 KB

4

If you render to an animation, most likely you are using a codec that does not support an alpha channel so will ignore the alpha input of the composite node.

Try this node setup

Screen Shot 2015-09-09 at 17.46.30.jpg1884×1112 172 KB

Also ensure under Render / Post Processing you have enabled the Compositor

5

Thanks Richard,
That’s done the trick.
So much to learn…
Regards,
Rob

6

Thanks Richard,
That’s done the trick.
So much to learn…
Regards, Rob