If you have the patience you could:

1. Save the video from Vegas as an image sequence

2. Use a graphics program (Photoshop, Affinity Photo, Gimp, etc) to remove the background from each image, (Decide whether you want to include the shadow). Some graphics programs allow macros to help automatic processing a set of images.

3. Import the image sequence back into Vegas.

The results will vary depending on how much care you have taken in the graphics program.

I assume you are using Uncharted 4 so here is a similar character from that game

I have used that process for original video, but I don't think I would have the patience to do it for a game character.

Problem with Photoshop Actions is there is no motion estimation, just a bunch of stills. On my tests the results were predictably horrible.

Chroma key requires a chroma, i.e., a color, in the background. Your background is almost gray, same as the foreground, so the chroma key will not be of much help there.

Gosh, Vegas can do this. I'm surprised the old-timers don't remember the Vegas "difference mask".

If this forum still contained a competent search engine (it doesn't) or if the archive search was competent (it is awful as well) you could find all sorts of great posts explaining how to do this. Basically, a difference mask allows you to use any static background in exactly the same way as a green screen. You can "key" out the static background and replace it with anything else you want. As I understand it, this is exactly what you want to do.

The original tutorial on this subject, done by one of the Sonic Foundry engineers, is still up:

Two Cat Demo

It was really great, in the old days, where the engineers actually used the product and shared their really cool "secrets" with the user base.

The "two cat" example is more complicated than what you want to do because he managed to composite two shots of the same cat into the same picture.

Here's another example, from my own archive, that is exactly what you want to do. About ten years ago good friend and fellow entrepreneur (he's one of the best I've ever met) rented a function room in Vegas for his wife's birthday and invited a huge crowd. The show "American Idol" was in its 2nd or 3rd year, and at the height of its popularity. He wanted to surprise her by singing Stevie Wonder's "Happy Birthday" as an AI contestant. He locked down his camera and recorded himself singing in front of a doorway. No decent lighting, no nothing. He sent that to me along with a DVD of the first two seasons of the show. I then went through and found appropriate clips to intercut with his performance. I was able to create a background of the AI set by cloning out a long shot of one of the contestants. I used that as my new background (i.e., it was what I used to replace the walls and doorway in his house). Fortunately, he started the camera with no one in the scene, then walked into the scene, giving me a perfect shot of the background that I wanted to remove. Lacking that, you can Photoshop out the foreground object, but the background is then never quite perfect.

Here is a link to my ancient use of a difference mask:

American Idol "Contestant"

You'll see a few places where the "key" isn't perfect. With enough patience this can be overcome with a combination of the median filter and garbage mask, both of which are explained in the tutorial.

There have been a few dozen posts on this in the past, and if you use Google search on the archive of the old forum, you can find them by restricting the search to just that site. The search provided by Magix is totally incompetent and completely broken.

If you want, I have a Vegas project file (Vegas 13) that I created just two days ago, using exactly this technique because I needed to remove the watermark from some stock video. I bought the video, but the purchased version didn't perform like the demo, and the company wouldn't fix the problem so, being under a deadline, I simply removed the watermark from the version that worked. I figured that since I paid for what turned out to be a broken version, I should be able to use the demo version, so I don't think I was violating any laws.

Just PM me and I'll send the difference mask Vegas 13 project file to you. And, if you want the Vegas project file and all the media used in that Cat demo from all those years ago, I still have that as well.

This is a fairly advanced technique, involving parent-child tracks, masks, track compositing, and other features of Vegas that you may not yet have explored. If so, and if you are willing to do the work, you will open up a new and vast expanse of capabilities and creativity that the original engineers loaded into the program, way back in version 4-7, when the program really came of age.

P.S. Depending on what you're actually trying to do, you can also just use a simply mask (found in the pan/crop dialog). That's how I did this simple example that I posted in another forum for someone about six months ago:

Wow, I just inserted that link, but first looked for a way to embed the YouTube video. Does this pathetic home-brew forum software not even provide for that? Why doesn't Magix just buy some decent forum software, like every other company in the world? This stuff has been around since the days of the BBS (remember Wildcat software?). There are dozens and dozens of really important features, all missing from this bad hack. that really improve the experience for the users who paid big money for this software and expect a professional forum for that expenditure.

[edit] It looks like it sort of embedded, although it doesn't play in place like a normal embedded video. Non-standard UI is generally not a good thing.

The EVENT PAN/CROP does allow for masking, but how do I remove that background still? See here: https://imgur.com/a/QJOfN

Gosh, Vegas can do this. I'm surprised the old-timers don't remember the Vegas "difference mask".

If this forum still contained a competent search engine (it doesn't) or if the archive search was competent (it is awful as well) you could find all sorts of great posts explaining how to do this. Basically, a difference mask allows you to use any static background in exactly the same way as a green screen. You can "key" out the static background and replace it with anything else you want. As I understand it, this is exactly what you want to do.

The original tutorial on this subject, done by one of the Sonic Foundry engineers, is still up:

Two Cat Demo

It was really great, in the old days, where the engineers actually used the product and shared their really cool "secrets" with the user base.

The "two cat" example is more complicated than what you want to do because he managed to composite two shots of the same cat into the same picture.

Here's another example, from my own archive, that is exactly what you want to do. About ten years ago good friend and fellow entrepreneur (he's one of the best I've ever met) rented a function room in Vegas for his wife's birthday and invited a huge crowd. The show "American Idol" was in its 2nd or 3rd year, and at the height of its popularity. He wanted to surprise her by singing Stevie Wonder's "Happy Birthday" as an AI contestant. He locked down his camera and recorded himself singing in front of a doorway. No decent lighting, no nothing. He sent that to me along with a DVD of the first two seasons of the show. I then went through and found appropriate clips to intercut with his performance. I was able to create a background of the AI set by cloning out a long shot of one of the contestants. I used that as my new background (i.e., it was what I used to replace the walls and doorway in his house). Fortunately, he started the camera with no one in the scene, then walked into the scene, giving me a perfect shot of the background that I wanted to remove. Lacking that, you can Photoshop out the foreground object, but the background is then never quite perfect.

Here is a link to my ancient use of a difference mask:

American Idol "Contestant"

You'll see a few places where the "key" isn't perfect. With enough patience this can be overcome with a combination of the median filter and garbage mask, both of which are explained in the tutorial.

There have been a few dozen posts on this in the past, and if you use Google search on the archive of the old forum, you can find them by restricting the search to just that site. The search provided by Magix is totally incompetent and completely broken.

If you want, I have a Vegas project file (Vegas 13) that I created just two days ago, using exactly this technique because I needed to remove the watermark from some stock video. I bought the video, but the purchased version didn't perform like the demo, and the company wouldn't fix the problem so, being under a deadline, I simply removed the watermark from the version that worked. I figured that since I paid for what turned out to be a broken version, I should be able to use the demo version, so I don't think I was violating any laws.

Just PM me and I'll send the difference mask Vegas 13 project file to you. And, if you want the Vegas project file and all the media used in that Cat demo from all those years ago, I still have that as well.

This is a fairly advanced technique, involving parent-child tracks, masks, track compositing, and other features of Vegas that you may not yet have explored. If so, and if you are willing to do the work, you will open up a new and vast expanse of capabilities and creativity that the original engineers loaded into the program, way back in version 4-7, when the program really came of age.

Awesome response! Thanks a ton. I am not sure this forum has PM but you can email me vegaspro22 at gmail dot com and we can discuss? I may even pay someone to crop him out, maybe you can help?

I sent you a PM at the email address you provided, and included the project file and all the media from the difference mask I created a few days ago. I suggest that you continue to post your questions here in this forum because there are far more people here who can answer more broadly than I can, and because I am not going to have much time in the next several weeks, as my daughter's wedding approaches.