Play a track backwards

I have a clip of a room with a window at the end. The clip pans left to right. The window is overexposesd. I have a still photo taken of the room at the end of the pan, with the photo correctly exposed. The camera was on a tripod for the pan and the still.
I’ve created a track in Mocha. I want to be able to apply the track to the photo. I need to somehow paste the track so that it effectively plays in reverse, taking the still photo from its end position to its beginning position, while the main clip plays forwards.
I have the feeling this should be fairly straightforward, but I haven’t managed to get it work. Any advice would be appreciated.

Hi Mary, thanks for the reply. I’m trying to use the insert method, following your troll tutorial.
For some reason, when I import the still, it comes into Mocha very small. It’s about an inch in length on the screen. It seems to do this regardless of the image size I export from Photoshop. Because of this, I’m finding it difficult to align the imported image to the Mocha footage.
I’m getting the imported image into all kinds of weird and wonderful shapes using the handles on the surface tool, but none of them are anything like the shape I’m trying to achieve!

Hi Mary,
Clicking “Align Surface” helped, somewhat, and I was able to get closer to lining up the image. I’m now thinking that I might be better using the AE plugin. The first run was a proof of concept. The still image is going to need somework to blend in well with the movie clip, and as far as I can see using the AE plugin will make it easier to modify the still image. I’m on a slow dial-up tonight, so I can’t really do Skype, but I’ve uploaded some images so that you can see what I’m trying to do.
This (ImageShack - Best place for all of your image hosting and image sharing needs) is the last frame from the clip. I have several still images taken from exactly the same position, with the same camera, same focal length, and differing exposures. This (ImageShack - Best place for all of your image hosting and image sharing needs) is where I ran my first track. I had to do quite a lot of manual adjustments to get a roto, which is still not perfect. Would you recommend using the same area for the track in AE, or is there a better placement for the spline?

I could to - I think! To be honest, I’ve watched a lot of tutorials, and read the docs, but I still haven’t really got my head around what the Surface Tool is. I’ve seen several examples of clicking the Planer Surface button, and using that as a visual aid for assessing a track. And Steve Wright mentions in one of his tutorials that placement of the Planer Surface is important when exporting corner pin data, but I don’t feel that I have a clear understanding of what it is, or how to use it.

Yes, thanks. That helps me understand what it is. I guess its importance depends on exactly what you are exporting. If you are exporting just a track, then no data for the Planar Surface needs to be exported. Whereas if you are exporting, say, shape data (?), the size of the Planar Surface is needed. Is that correct?
I’m still having a little difficulty resizing the still. Like this (ImageShack - Best place for all of your image hosting and image sharing needs). What exactly do the two bounding lines mean? Is there a way to reset the Surface, and start again? The only place I’ve been able to nudge points around is in the Adjust Track tab. Is there a similar feature available in any of the other tabs - tracking, insert, etc.?
Thanks for your help.

OK. Thanks again for you help. I’ll play with it some more, and give you a shout if I get stuck. Just a couple of last questions:
I don’t quite follow your instructions for resetting the surface. To create a new layer, do I duplicate the existing one? And then …?
Once I’ve linked an inserted image, what are my options for exporting? Can I send the clip+ image back to AE? Can I render a new clip directly from Mocha?

Thanks for that. I’ll try it with your recommended splines.
Just to clarify, the issue I’m having is the white triangle that appears in the top right corner of the right hand window, in this clip (Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.). I probably confused matters by talking about transparency. That was just because I was trying to get clear in my own head exactly what the triangle is.
To recap what I’m trying to do: I want to replace all the windows in the footage with windows in the still. To achieve this, I’m using the following methodolgy.

  1. Track the windows in Mocha, and create shapes for the window panes.
  2. Export the shape data in Mocha and apply it to the footage in AE. This creates a mask. I invert the mask to cut a hole in the footage, revealing the still on the layer below.
  3. Export the tracking data in Mocha and apply it to the still in AE. This creates corner pin key frames for the still, causing it move along with the footage, keeping the windows in the still in sync with the window holes cut in the footage by the mask.
    Once everything is lined up, I can go back and colour correct the entire thing to make it all hold together more believably.
    I’ve already downloaded your new tutorial and watched it through a couple of times. It’s very helpful.
    Cheers,
    JB

I’ve tried creating a track similar to the one in your screen grab, like this (Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.), but the results are pretty much the same. I’m still seeing the white triangle in the corner (which will be black/yellow in the files I uploaded yesterday).

Hello again! I’ve been continuing to use Mocha, and I’ve had mixed results. Sometimes, I get exactly what I want, other times I can’t get it to work, and I don’t understand why. If you have a moment, I’ve uploaded an example of the type of problem I’m having. I’m not sure whether the problem is caused by some fundamental misunderstanding on my part, a bad track, or a difficult clip.
The project is a window replacement. One window was perfect. The other, I couldn’t get to work. The surface/insert tracks inwards, leaving part of the window showing just transparency. This is the link (Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.). If you have a moment to look at it, that would be really helpful.

Looking again at your suggested spline, I see that you have the surface lined up with the window. Placement of the surface has been the one thing that I’ve found most difficult to understand.
In the documentation, it gives a procedure to use if the insert is smaller than the footage -create a precomp, etc. However, my insert is not smaller than the footage. It’s the same size. The only part of the insert I’m interested -the window- is smaller than the footage, but the insert itself - the png still - has the same dimensions as the footage.
What I’ve been doing is going to the first frame in Mocha, and hitting align surface. I did this because of the reasoning outlined above: the png file, to which the track will be applied, has the same dimensions as the footage. I wonder if this is where I’m going wrong.

I have tried it in Mocha Pro, and I get exactly the same result. Like this (Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.).
I’ve watched the youtube tutorial, but I don’t think that’s going to help. I am seeing this problem even when I use an insert that is the same size as the footage.
I really think that it’s a problem with the track. If you watch this scrub through (Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.), you can see that the surface clips the corner in exactly the same it does in the final output. That’s happening in Mocha, before I go into AE, before I do anything with inserts. It’s just the track. I don’t see that behaviour in the previous, successful tracks I’ve made.
I really appreciate your patience, here, and the time you’ve put into this thread. But I’m of the opinion that this is a case where it’s simply not possible to use Mocha to do what I want. It’s not possible to get a solid track on the window panes that I want to replace.

I’m afraid you’ve lost me there, Mary. I can’t visualise the steps required in the process that you describe.
One thing I have noticed is that if I scrub through the track, then surface cuts off the corner in exactly the same way that I’m seeing in AE. That’s what made me wonder if it was the track itself that was causing the problem. Here’s a screengrab (Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.).

Still no luck, I’m afraid.
—Quote—
You need to make a larger than your composition precomp and place your insert into that comp.
—End Quote—
So, I enlarged the still in Photoshop by 25%. This still is 2400 x1350. I took this still into AE, and put it into a comp 2400 x 1350
—Quote—
You need to precomp that into a comp that is the size of your regular comp.
—End Quote—
So, I precomped the 2400 x 1350 still layer. This precomp defaults to the same size as the original - 2400 x 1350, so I manually changed it to 1920 x 1080.
—Quote—
You need to apply your data from mocha as the fullscreen, aligned surface data.
—End Quote—
So, in Mocha, I aligned the surface at frame 1. I exported the tracking data and pasted it into the 1920 x 1080 precomp.
When I paste the tracking data, the image is moved up and left, leaving a black strip on the bottom and right of the image; the aspect ratio is wrong, and the triangle is still there… sorry … Here’s a screengrab (Microsoft OneDrive - Access files anywhere. Create docs with free Office Online.).

Ahh - yes. That certainly sounds as thought it will be the problem. Head duly slapped, and banged on desk for good measure! I’ll give it another try, later on today. Because the modified still makes the insert bigger than the footage, I think I’ll have to go through the extra AE precomp steps to make it work.
I’ll also have a look at doing it in MochaPro. The first time around, I didn’t go as far as rendering it. I scrubbed it through, and I could see that it wasn’t working, so I stopped there.
I’ll let you know how it goes. Enjoy Vegas!

Hi there,
You should be able to adjust the side of the insert by moving the surface tool around OR by adjusting the clip size in the clip tab by cropping the image with the yellow dotted lines that appear around your footage in the clip tab or when you view the clip in the viewport.
If your insert tool is warping in ways you don’t need it to be in, adjust the surface in the track tab instead, where you have less warp options. If you need interesting warps, try using the grid warp tool in the insert tab.
If you’re still having issues, I am Mary.Poplin on skype and we can try to screenshare so I can see what’s going on in your shot.
Cheers,
Mary

If you are compositing in after effects using mocha AE, it is as straightforward as:

  1. Making sure your clip settings in mocha and your composition and footage settings in AE match exactly, so frame rate, aspect ratio, and image size must all match between mocha and ae,

  2. aligning the window in a pre-comp that is the size of your clip,

  3. finding the right frame where the track lines up in mocha,

  4. hitting the align surface button,

  5. clicking the export tracking data button (use AE corner pin),

  6. copy that track to the clipboard,

  7. and then in AE make sure you are on the first frame of the comp and paste the data in.
    If you are in mocha Pro, you just use the insert module by:

  8. importing your still image onto a layer that is attached to your good mocha track with the insert clip drop down menu,

  9. aligning the still with the surface tool on the frame where it matches best

  10. Going to the insert tab and adjusting settings (you’ll probably want to click motion blur on to get movement blur to match)

  11. And rendering forwards and backwards.
    Let me know if you have any questions!
    Cheers,
    Mary

Can you just crop the image to the size of the window and line the surface tool up to the window with that image to make sure all four corners are lining up?

OK. Think of it as a representation of the corner pin, yes. That’s a good way to think of it. It’s basically the tool by which you line up planes to the track. See, the track is tracking planar data, and to composite something with that planar data you need a tool that will show you what whatever you want to place in the scene will do when it moves along with the track. Thats where the surface tool comes in.
If you align the surface tool to the four corners of the door, you can fill in the door with an image, if you line up the surface too to the entire frame (align surface) you will align an image to the entire frame of the shot.
In order to use align surface to full effect you have to align the surface to the exact frame where the image you are trying to composite into the shot lines up with the moving shot. So it it lines up on frame 43, you hit align surface on frame 43. If it aligns on 74 you hit align surface on frame 74. It will then warp correctly with the track from that frame on.
Do you understand now?
Cheers,
Mary

Hi there.
Ok, a couple of things might be happening. Again, without seeing your shot in motion its hard to tell.

  1. Is your track solid to begin with? Check it in the “track” tab by turning the grid on and seeing if the grid moves along with the object you are trying to track.
  2. You shouldn’t even need to use the yellow “curve” lines at all for this shot, you should just align the corners. You can do that in the track tab instead of the insert tab for LESS point options. Which it seems like would be good for you.
  3. You should not be using the adjust track tab to move your surface ever, you only use adjust track to adjust your track. Everything in mocha is a child of the track, so moving the surface won’t help you, only fixing the track will.
  4. You can reset your surface easily and completely by making a new layer and linking the track to the old layer. Align the surface in the track tab first before you go to insert.
  5. If you’re just trying to replace the window, crop the window replacement to the actual size of the door and bring that new file in instead of your full size shot you’re using.
    If you still have problems, send me an email with the best number to reach you at and I’ll walk you through this.
    Cheers,
    Mary

To create a new layer you have to create a new spline. Just connect a few points and you’ll have a new layer.
Attach that layer to the track by using the “link to track” drop down menu.
Adjust the surface to where you want it.
If you are in mocha Pro, you can render the insert out of mocha Pro with an alpha right into your results folder.
If you are in mocha AE you can export a corner pin to After Effects to drive a corner pin in after effects. BUt you won’t be able to export the “insert” to After Effects from mocha, just the corner pin.
:slight_smile:
Mary