Prescan surface area for movement before editing?

Hi, just downloaded mocha pro 2020 to give it a spin in LE mode.
Basically, I’d like to use the app to remove students moving their heads in recorded lectures.
So, the area in which this happens is basically always the same (right edge of the video frame), but I can’t predict when.
In order to avoid to have to skim through the whole recording to find out the culprits, would there be an option in mocha to kinda set a tracking area on forehand and to have mocha scan that area for movement in accelerated mode so as to pin down the frames that I need to edit afterwards ?
That would be a great timesaver for me if this option exists.

There’s not a way to currently do this but that is an interesting feature request I can let @martinb know about.


Thank you, Mary.
How would you suggest I proceed without that feature? Do I put the rendered stills in a timeline (e,g, premiere)?

So you can still use the remove or more preferably insert to replace the heads, that’s not the issue, we just don’t have a way to automate the frames the heads are on. You will have to do that manually.

But more than using the remove tool, you really probably want a performance replacement for those heads. You can find a tutorial here on that technique:

Can you try that and let me know?


Mary – Just to be clear: You’re saying that once all the painting is done in Silhouette, I need to render and export the finished product as stills. I can’t automate the stills in Silhouette or anywhere elsewhere? And I can’t simply put the stills in a timeline?

I didn’t mention Silhouette at all, I am confused about where that came from.

You can’t just drop stills into the timeline unless the shot is totally locked off. And even then you still have to track people if you’re going to replace their heads.

If your shot is locked off and the students aren’t hardly moving, you can just put a still frame of the offending students over that section or a series of frames repeating in a loop over that section, and feather in a roto shape around them to blend but that might give you noticeable errors in your results.

All I am saying is there’s no automated way right now to avoid having to skim through the whole recording to find out the culprits moving their heads automatically in Mocha Pro. But that there are other performance replacement techniques you can use depending on the shot to fix your issue manually.


I believe you are mixing your thread from the Silhouette forum here in the Mocha forum. For clarity:
The answer to that post is Silhouette exports image sequences. Most editing applications can import sequential frames and export.

Ah, the icons were so similar I did not notice they were coming from different users. I see, this must be a reply by email issue instead of a reply by the forum issue.

Hi, thanks for the tut, which I watched with interest. Looks more for advanced users TBH. I’m just stepping in the ring… Removing objects seems like a quicker solution for me, at least for now…
There’s two more questions I’d like to ask :

  1. Is there a way to remove student’s reflections on the whiteboard ? The difficulty I foresee is when the lecturer actually writes something on it, so how will I be able to simultaneously mask the reflexion while still being able to see what’s written ?
  2. Editing an HEVC recording in DaVinci (with Mocha as plugin) works (a bit stuttering when doing the playback), but exporting to HEVC again is way slow (6 hours) and quadruples the original size. Is there a way to have DaVinci apply Mocha’s edits only to particular frames ? Would that reduce size and time for export?

NB I tried to import HEVC media in Mocha’s standalone version, but that didn’t work. Does Mocha 2020 support HEVC ? I was surprised it also refused recordings that were shot in .mov format (iPhone). Any reason for this ?

iPhone’s shoot in variable frame rate. So, that’s probably why the footage is being rejected by Mocha. You’ll need to convert the footage into another format that is more conducive to editing, I’d go with either ProRes422 or DNxHD.

Additionally, if the shot is locked down and you have a student’s head slide into the frame a little every so often, just scale the entire shot by 10% or so and the errant head won’t enter the side of the frame. You can do that directly in Premiere.

As for the reflection on the whiteboard… the effort to fix it far outweighs the accolades you’ll likely get for in-depth VFX work on a college lecture video.

Thanks for the reply…

So I should just convert this in Handbrake to a constant bit rate? Using Filmic Pro to shoot, but can’t find a CBR option there. Any iOs app that’d allow me to do this ?

As a matter of fact, what I did was the following : converted the iPhone recording to HEVC with handbrake, then used Apple Compressor to convert it to ProRes442. Now this transformed a 300 Mb file to a whopping 35 Gb one and the standalone version of Mocha wouldn’t let met import it…

Ok, and with DaVinci ? (I’m being told its learning curve isn’t that steep…)

Ok, but let’s say I would like to put the effort in it anyway, I guess I have to play with cleanplates right ? Already checked out a few tuts about this. But is it even possible to have both cleanplates, reflection removal and dynamic writing on the whiteboard?

Can you not just import the iPhone footage into Adobe Media Encoder and convert it to ProRes422 with a standard frame rate (ie, 29.97) - CBR is Constant Bit Rate and has nothing to do with frame rate.

Yep. Files that make your editing life easier are less compressed.

I don’t know, I don’t use Resolve. I thought you said earlier you were using Premiere to edit. If so, select the clip in the timeline, go to Effect Controls and increase the Scale parameter to your liking.

For the reflections, I am a casual Mocha user (usually tracking logo blurs, etc) It’s hard to gauge without seeing the shot.

Got mixed up indeed. Thought you were referring to VBR, as the app I’m using to shoot videos is not the Apple one, but Filmic pro, that allows me to fix the frame rate. Mostly I’m shooting at 30 fps.

Will check out the rest. Thanks.

Tried to convert my HEVC file through Adobe Media Encoder as suggested (Apple ProRes 422HQ) yielding a .mxf file which Mocha 2020 standalone wasn’t able to open. What did I do wrong ? Then tried again in .mov format and still no go…

As to my replacement of ‘moving heads’ in my video shooting, wouldn’t the easiest way to get rid of these intruders be to replace the area in which they occur by a cleanplate screenshot, overlaid on the whole of the sequence rather than actively tracking the movements themselves inside it ?
I mean, it’s a static background anyway, so it wouldn’t make any difference. Would there be a beginner’s tut out there to easily achieve this ? Thanks.

You can find supported formats for Mocha Pro stand alone application here: Boris FX | Mocha® 2020 User Guide

If using Mocha as plugin, it will support all the files the host application supports.

The remove is going to be tricky for this, potentially, but hopefully it will work for you.

For the student reflection, you can try to key what is written and blur or take the contrast down on the board depending on how reflective the board is. That might work, or it might not, it’s going to depend on the shot and since I can’t see it I can only guess at solutions.

Unfortunately, Resolve doesn’t support Mocha plugins rendering to the timeline properly yet, we are still working with them for a solution so you will have to render your footage and export it out of Mocha Pro and reimport it into Resolve. You will need to find a codec and file format you can live with size wise that Mocha and Resolve both support and then use that. Mocha won’t render HEVC but it will render tiffs, jpegs, pngs, exrs, and more you can find in out supported file format list linked by Ross.


Hi and thanks for the reply. As the background is still, wouldn’t it be easier to just do a still image replacement (f.ex. with screenshot or cleanplate?) for that section of the recording in which the movements occur ? Would there be an easy tut for beginners for that ?

Only if the people aren’t moving and the camera isn’t moving and there’s no foreground occlusions. Once people and cameras start moving replacing with a still image becomes a problem.

We do not have a beginner tutorial for replacing people with a still, but if the camera is locked off, it’s as simple as dropping the still over the people, making a mask around the area you want to have replaced, and holding that frame for the length of the shot, and adding grain back to it.

If you have someone or something moving in front of them, then you need to start using rotoscoping to composite that back over the top.

I really recommend the getting started with Mocha series or the Mocha Fundamentals series for beginners.


Hi. With the latest mocha release, would this optional motion detection feature in a selected area have seen its debut ?

We aren’t there yet. But we do have some very interesting features coming. Stay tuned.