Problem getting clean key with Primatte Studio or Chroma Key Studio

Hi!

I have 4 videos where I’m trying to key out the background wall and just am not having much success with either BCC Primatte Studio or CC Chroma Key Studio. (host is VP17, OFX).

Auto-Analyze says it can’t do it and I need to do manual sample. Manual sample is giving crazy weird results. Obviously I can mask the outside with a rectangle but it’s still diong a poor job in what appears to me fairly uniform (obviously with shades).

Any tips would be really appreciated… tight deadline!

It appears you have something hanging on the wall on an angle. Light is hitting it and it is casing shadows.Those shadows are the problem. Can you scale up the video, reposition it and crop out what remains?
Next time,if possible. Shoot with that object out of the picture.

That is a really tough shot. Primatte Studio and Chroma Key Studio are specifically designed to key green/blue screens, not arbitrary background colors, and particular not neutral backgrounds. Those filters just won’t work on a gray background like this. The luma in her shirt is also very similar to the background so a lot of the other BCC keying filters will have a hard time isolating this. I think you’re a Vegas user so I’ve attached a very rough mockup of one approach in Vegas. It duplicates the track and puts a holdout copy on the upper track to preserve the interior of the foreground. BCC PixelChooser is applied to the upper track with Matte disabled, output set to Multiply Alpha, and Mocha used to loosely roto just inside the foreground. If you have a lot of motion in the shot this will take a much more thorough job of rotoing the foreground to really get it to work, but you could limit this to her shirt which is where the holdout is most needed. Then on the underlying track it uses two more copies of BCC PixelChooser, both set to Multiply Alpha. One copy uses Mocha for a rough garbage matte, again requiring a more sophisticated roto/tracking setup if there is much motion. The second copy of BCC PixelChooser uses the Key option in the Matte section to try to isolate the background wall color to key out the remainder while still preserving some edges. You could clone multiple copies of it to work on more narrow color ranges. Definitely not simple or awesome, but it’s a possible approach for this tough shot. Synopsis - holdout interior on one track, garbage matte + PixelChooser’s color key on second track.

Cheers,
Jason

ToughKey.zip (129.5 KB)

Yeah – I specifically asked them to shoot against a background with a contrasting color which is different from anything they are wearing, or their skin – this is what I got. Ugh.

Two related problem – getting Mocha to work properly.

  1. Inside Primatte Studio when I launch Mocha to create a mask (thought I might just mask out the subject instead of trying to pull the key color out), my center workspace (which normally shows the video) is black/blank. I tried disabling GPU use in the Mocha preference but same result. Also unplugged my 2nd monitor and restarted VP17 but same result.

  2. Auto-Analyze of Primatte Studio alerts “BCC Primatte Studio: Unable to auto-analyze this clip. Use Manual BG sampling to set the key color” Is it searching just for blue and green?

As mentioned in the other thread, can you make sure the current timeline indicator in Vegas is parked on the clip before launching the Mocha UI. That can be required to fetch host frames in Vegas. If that doesn’t help, please send your BCC and Mocha log files.

As for Auto-analyze, Primatte Studio is specifically designed to work with blue or green screens so that is what the auto-analyze is looking for and that is why it reports being unable to auto-analyze this clip. But even if you manually sample this clip, Primatte Studio is not likely to succeed at keying out a gray background since it is specifically looking for colored screens.

I hear you, and VERY much appreciate your help. I watched “tutorial #1” on Primatte again and am impressed to see I can keep grabbing new samples to add – it’s getting pretty close and may work for me here… again, Mocha tracking not possible without the preview which I don’t have time to troubleshoot properly (where would I find the BCC and Mocha log files… would they have info even if there are no raised errors?). I definitely was on a visible frame in Vegas … since it’s applied to the track as a compositor though, there really no longer is “the clip” to be parked on.

The BCC and Mocha log files would be here:
C:\Users\YOUR_USER_NAME\AppData\Roaming\BorisFX\Logs\BCC.log
C:\Users\YOUR_USER_NAME\AppData\Local\Imagineer Systems Ltd\imagineer.log
If you send them, please zip them and send via private message on the forum or email to jclement at borisfx dot com
They might indicate errors if any are happening under the hood. This sounds more like a temporal alignment issue however. The black screen you mention is exactly what you would get for “empty” parts of the timeline when applied as a custom compositing filter in Vegas. try scrubbing the timeline in the mocha UI to see if the footage appears somewhere else in time. If you could send along a project file we could take a look.

Cheers,
Jason

Thanks Jason – I’ll definitely follow up after I get this project wrapped up. I think I have to use Primatte and say it’s “good enough” – don’t have the time to figure out your better workflow.

Wish I could pay someone to just get a cleaned/keyed version of those 4 video files LOL