ADOBE AFTER EFFECTS: Forum Expressions Tutorials Creative Cloud

Mocha Pro: replacing screens that move in and out of frame

COW Forums : Adobe After Effects

<< PREVIOUS   •   FAQ   •   VIEW ALL   •   PRINT   •   NEXT >>
Glenn Chung
Mocha Pro: replacing screens that move in and out of frame
on Oct 25, 2016 at 7:02:56 pm

Hey all,

I have a shot that includes multiple screens: flatscreen TV, iPads, laptop, and digital frames, all on different planes and at at different distances from the camera. The shot starts close in on an iPad, then pans and zooms out to reveal all the rest of the screens in the room.

Is there a recommended technique to allow Mocha Pro to solve for the screens that move into and out of frame? It seems like Mocha Pro is OK if most of the screen remains in frame, but does not like it when the screens appear or disappear...

Thanks very much.


Return to posts index

Dave LaRonde
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 25, 2016 at 7:15:43 pm

Track 'em backwards.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


Return to posts index

Glenn Chung
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 25, 2016 at 7:17:29 pm

Yep, I do indeed use backwards tracking, but as soon as 50% of the screen moves out of frame Mocha Pro no longer recognizes the defined plane and the controls points start sliding around. Do I just have to "fix" the control points manually and keyframe?


Return to posts index


Dave LaRonde
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 25, 2016 at 9:46:42 pm

I think it might be the footage. Mocha doesn't play well with certain video codecs, the ones that don't contain complete information for each & every frame.

Try transcoding the problem clip -- with handles -- to a Quicktime Movie in the ProRes 422 (if you have it), JPEG 2000, Motion JPEG or PNG codecs. It will probably work better.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


Return to posts index

Dan Tran
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 25, 2016 at 11:29:10 pm

Hi Dave,

I'm having the same issues. In my shot, I am zooming out of a picture to start the scene and panning away from the picture at the end of the scene. Mocha is able to track the picture as the camera pans away but the tracker goes out of whack when zooming out to start the scene. I've tried tracking backwards and to transcode the clip using the ProRes422 codec as you've suggested but I'm still having the same issues. Do I need to manually adjust the tracker frame by frame?


Return to posts index

Roei Tzoref
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 26, 2016 at 12:42:46 pm

Establishing a proper mocha workflow depends how the shot looks like. Can we see the footage? ( both of you)

Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials


Return to posts index


Dan Tran
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 26, 2016 at 3:52:27 pm

Hi Roei,

Here is my footage I'm working on:


Return to posts index

Dave LaRonde
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 26, 2016 at 6:12:35 pm

Available light. No good contrast range. Ugh.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


Return to posts index

Dan Tran
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 26, 2016 at 8:03:56 pm

Hi Dave,

This is the raw footage. Should I do my color corrections first before tracking in Mocha?


Return to posts index


Roei Tzoref
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 26, 2016 at 9:17:55 pm

[Dan Tran] "This is the raw footage. Should I do my color corrections first before tracking in Mocha?
"


usually no. sometimes you can increase the contrast to help mocha but you can actually do this while in mocha by changing the color space. I was able to track your shot using shear and not perspective and setting the zoom parameter to help mocha with the rapid zooming in. 4% at the start and later (where you see the green keyframe) set it 24%. with a few tweaks here and there and you can get it to work.



next time try a better texture. it does not have to be green if you are not keying anything. this would help mocha a lot more then a few faded crosses. as for the start of the shot you can scale this manually because the there is no tracking data at the start

Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials


Return to posts index

Dan Tran
Re: Mocha Pro: replacing screens that move in and out of frame
on Oct 26, 2016 at 11:27:42 pm

Thank you so much Roei!!! This helps so much. And also thanks for the tips!!


Return to posts index

Glenn Chung
Re: Mocha Pro: replacing screens that move in and out of frame
on Nov 9, 2016 at 1:01:17 am

Hey sorry about the delay getting test footage up -- we've been on location shooting quite a bit. So here is the link to my test footage, originally shot on ProRes HQ 1080p23.976 but transcoded to M4V for size purposes. I have to track and replace all 3 screens...

<iframe src="https://player.vimeo.com/video/190804322" width="640" height="360" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
<p><a href="https://vimeo.com/190804322">BLADE1_S001_S001_T022</a> from <a href="https://vimeo.com/user4527139">GSC</a> on <a href="https://vimeo.com">Vimeo</a>.</p>


Return to posts index


Roei Tzoref
Re: Mocha Pro: replacing screens that move in and out of frame
on Nov 9, 2016 at 10:00:21 pm

[Glenn Chung] "It seems like Mocha Pro is OK if most of the screen remains in frame, but does not like it when the screens appear or disappear..."

actually this is exactly where Mocha excels traditional point tracking. of course you need to have enough information and if necessary you can manually track to object out of frame which usually is usually only a few frames and relatively easier than trying to get it automatically.

about your shot. you would better of turning off the screens or use a grey background for the screen (load up a grey background). you can see how the glows scale up as you lose focus this means more compositing for you . you are also going to have to deal with the reflections. mocha does not need much to track well. good lighting and some texture and color.

as for the tracking planes in you shot. where the screens go off there may be some manual tracking but even without it look how it sticks. these are the settings. there maybe a few corrections here and there but this is perfect for mocha and could be done very easily.




Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials


Return to posts index

Glenn Chung
Re: Mocha Pro: replacing screens that move in and out of frame
on Nov 9, 2016 at 10:02:38 pm

Cool, I was wondering if just using shear would work with this shot. Thanks so much!


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]