Mocha Pro Remove Tool - How to solve the issue of Mocha Remove not actually removing the objects
Hi, this is less a question than me simply posting a tip here so I can search in the future when I run into the same issues with Mocha Remove. Plus, by posting it publicly, someone else might stumble upon this answer. Also, would love additional tips on this thread, so chime in!
QUICK ANSWER first: I've seen this issue posted a few times here and there, and I've done some hair pulling this week before I figured it out. If you're using the Mocha Pro Remove Module and you find that, when rendering out the final sequence, it suddenly stops "removing" the foreground object (while continuing to render and spit out uncorrected frames), then do the following: Under the Search Range of the Remove tab, try setting the "# Frames Before" box and the "#Frames After" to the ENTIRE length of your shot AND make sure the frame Step is set to 1. I'm not saying you HAVE to do that. I got it to work once by only having that range be about 25% of my 600 fr shot. But I found that if I went and made adjustments to my roto spline and re-rendered, suddenly the removal process would stop on arbitrary frames. Setting it to the entire sequence length ensured that the "removal" would continue to the end of the shot every time.
Having said the above, if you have a long sequence at 1080 this technique will not be practical due to the processor/memory overhead required UNLESS you're using Cleanplates and have the box checked which says "Use Cleanplates Exclusively".
Ok,now more details that I learned.. the. hard. way.
1. Read and re-read the Remove docs. They are woefully short, but they will help you avoid some easy mistakes.
2. VERY IMPORTANT: The Search Range numeric boxes are KEYFRAMEABLE. If you have the red A (autokey) enabled, as you change values in those boxes while the timeline cursor is non-zero, you are actually setting keyframes in the timeline. Either it's a bug in Mocha Pro, or in my graphic card, but the green keyframe indicators did not show up in the timeline (except when I clapped my hands and turned around once, meaning they might pop on randomly). I was changing those parameters and never realized that I was setting keyframes. That resulted in so many render errors for me.
3. Also VERY IMPORTANT - This should be more clearly written and stated in the tutorials: Checking the box: "Use Cleanplates Exclusively" puts Mocha in a very simple image replacement mode. All of the cool voodoo that Remove does behind the scenes, sampling the background, etc. is turned off (or mostly turned off) and it renders very quickly as a result. My frustrating experience this week had to do with trying to use cleanplates AND have Mocha do it's magic. I got the best results by always using "Use Cleanplates Exclusively". My guess is that most VFX artists use this technique.
4. USING MULTIPLE CLEANPLATES: This is something the manual mentions as possible, but I can't find any actual video tutorials about it. This is very powerful stuff, and I'm surprised the Mocha folks don't promote this more. Also, I would suggest this is much better approach than using the Remove voodoo algorithm.
a. Create your cleanplate by clicking on your tracked background layer, NOT your roto layer. It
creates a cleanplate with a frame # in the "Results" folder. If you're just using one cleanplate,
stop reading this, just make sure the frame # is set to "All". But if, say, you're removing tracking marks from someones skin and that person is moving around a lot, you're going to need more than one cleanplate. Move through your footage and create cleanplates at each moment when you think you'll need a different plate.
b. Open each plate in Photoshop (note that each image will have appended frame numbers) and paint out a clean plate and save it with the SAME APPENDED FRAME NUMBERS.
c. Import the plates into REMOVE tab and make sure that none of the Cleanplates have a frame number which says "All". If it does, change that "All" to the frame number from which that cleanplate was created.
d. This is where Mocha earns its keep. As it renders, it will use the corresponding cleanplates at their respective frame numbers and do a slow blend between them so you don't see a "pop" as it switches between cleanplates. Remmber to check "Use Cleanplates Exclusively".
e. The default roto spline "Edge Width" setting of "3" was always too hard an edge for me. I always took it up to "8" for a more seamless blend.
I know there's a way to do it (I saw it done in tutorials), but I couldn't figure out how to render out all my roto removal splines in one pass. I had to render each roto removal spline as a separate pass and then comp them all in AE using the mattes they created. When you do that though, make sure you change the output name in the output section of the REMOVE tab, or else you will overwrite your previous remove.
Hopefully others will correct or add to this long post. That's the beauty of the Cow.
Quick update. Mary responded to my tech support email. Some original problems I was having had to do with this footage being interlaced. I deinterlaced it in AE and brought it back into Mocha. That actually fixed other problems I didn't mention, though not the fact that the "remove" would quit arbitrarily.
Lesson being: Though Mocha seems to handle interlaced footage fine, I would recommend deinterlacing before you bring it in to Mocha.
Some good tips included in this post.
Here is a link to mocha Pro Remove Modules that discusses "Clean Plates":
And general mocha Pro Remove Module videos:
When working on advanced removes that involve multi-planes, I would recommend rendering in passes and saving your project at stages. You can keep all the removes in one project be changing the source and output directories in the project path of the Remove Module.
Multiple clean plates - I agree this is a very powerful workflow and very often necessary to give you the best results on difficult removes. I will see if there is a specific video, and recommend that we create a new one.
On that note wanted to also mention (2) advanced tutorial options for mocha Pro users:
Thanks Robert for sharing this.
Thanks for the tip of checking "Use Cleanplates Exclusively"!
If you want to add a bug to your list, clicking Edit with None for Cleanplate Clip crash Mocha Pro. :)
Be aware that mocha Pro version 4 is now available.
Please let us know if you are still experiencing the problem.