Beginner advice needed. Edit existing footage to change a persons position

[simondg]

Hi

I've got a specific video project in mind but being new to this don't even know where to start in terms of the feature set needed for the software to do the job.

Mostly I need to edit existing footage to change a persons position in the scene (or object) while the rest of the content obviously needs to remain, so a bit of background editing needs to happen.

I've been a long time user of Adobe PS and the print range of products -- but moving to video don't even know the technical terms for what I'm wanting to do, so any advice or points in the right direction would be most appreciated.

Thanks, Simon

[poisondeathray]

Hi

I've got a specific video project in mind but being new to this don't even know where to start in terms of the feature set needed for the software to do the job.

Mostly I need to edit existing footage to change a persons position in the scene (or object) while the rest of the content obviously needs to remain, so a bit of background editing needs to happen.

I've been a long time user of Adobe PS and the print range of products -- but moving to video don't even know the technical terms for what I'm wanting to do, so any advice or points in the right direction would be most appreciated.

Thanks, Simon

In general , you would likely need to rotoscope out the person or object (frame by frame). It's analogous to "cut outs" or making selections in photoshop, but done on video. But there are other methods and techniques that can by used to simplify isolating the object . This would be combined with a background repair (otherwise - if you remove the person, there will be a "hole" in the background) . Typical tools used for these types of tasks mocha pro, after effects, nukex

Usually you can't just simply "cut out" an object and move it, there is much more work to make the object or person "blend" in. This is the art of compositing. For example, the lighting will be hitting the person at different angles, shadows, interaction with other objects (even if they only "2D") compared to the other position

The details are important: it depends on how the shot is set up, what kind of camera movement, what kind of background footage is available for the repair (frames before and after) . The specific details will determine how you might approach this, and what software you might use - you need to provide more information

[Cornucopia]

Unlike Illustration/VectorGraphics, or 3D Animation, or even well-designed photo compositing, most of video is NOT left in a separate-object/layered state. It's all flattend down to a single combined, composite image.

Trying to undo that is like trying to unmix cake batter - once it's in the mix, you're basically stuck with the way it is.

Pros get around this by not shooting a person in a scene (if they expect to have to move him/her around), but instead by shooting the background plate separate to the foreground object (which is shot in Green-screen). Then modifications are done during the editing/post-production, and then ultimately added together to create the final image.

Now, if you are LUCKY, you might have a shot WITH FG+BG (foreground + background) and another, nearly identical shot with just BG. With a compositing app, you could do what's known as a "difference matte" which uses visual math in this way:

(FG+BG) - (BG) = (FG)

...giving you only the foreground (usually over black or "transparency"). But "nearly identical" leaves wiggle room for error (both in the resulting FG and in the remaining BG).

Otherwise, you're left with the most common fixit: rotoscoping. That is carefully tracing the outline of the desired object for purposes of using it as a "cutout". Then applying that cutout as the FG over a new/different BG.

If you are familiar to PS, look into AfterEffects. It does for motion what PS does for still images.

But remember, because of everything being in motion (often including the camera), everything becomes 1000x harder and more time-consuming.

Scott

<edit>dang, pdr, got there ahead of me again!