Identifying image regions

In MatchMover, you can load one matte for each sequence. The matte, however, must have the same resolution and number of frames as those of the sequence.

The matte can be loaded simultaneously with the loading of the actual film sequence if it is included in the alpha channel. In the File > Load Sequence or File > Load Images window, check the option “Use alpha channel as matte”.

The example shows a black matte that serves to focus the points on a moving car.

Following the child-parent hierarchy, the matte is listed in the Project window and Track window in the Image Sequences folder under the sequence it covers.

Displaying, hiding, and deleting mattes

If mattes are displayed, all the areas masked out are shown with the matte color and transparency in the 2D Mode. You can hide or show mattes by doing one of the following:

Select Display > Matte from the main menu.
Right-click in the Workspace and select Display > Matte.

The check mark beside the Matte option signifies that the matte is shown. Click the option to deselect it and hide the matte. You will see the full video footage.

To delete a matte, right-click the matte in the Project window and select Delete Matte from the pop-up menu.

Setting the matte properties

The Parameters Window lists the matte properties.

The matte’s Label and File Name
The Number of Frames in the sequence
The beginning and end Frames in the range
The Range of frames being used
The Interlace attribute that you can set to None, Upper field first, and Lower field first.
The displayed color and transparency
The Group attributes.

You can also select the channel being used by the matte sequence. Red, Green, Blue, Alpha, and Gray (for grayscale images) channels. However, if a matte has only certain channels, the other channels are grayed out.

Checking the option Inverted to invert the area that is masked. Optionally, right-click the matte in the Project window and select Invert to check the option.

Each matte is displayed using alpha blending, with customizable transparency and color for each. Mattes also can be tagged as “Group” with a label, and are therefore used to design a coherent rigid mobile object. While autotracking, each object is handled separately, and a group of the specified label is created with its tracks in it, and is calibrated as a separate moving object.

Drawing mattes in MatchMover

MatchMover’s Matte Drawing Tool allows you to draw binary mattes to identify areas. These areas can be excluded from the automatic tracking process, or used to identify rigid moving objects. Mattes are the result of compositing one or several contours, which are closed, 2D polygons, defined using control points and animated over time.

The Matte Drawing Tool allows you to place control points and, therefore, define contours. For any given frame, once you edit a contour, the frame is called a “keyframe” and the contours are interpolated in between keyframes.

A contour is active at the current frame if it effectively masks an area out. This is true for all frames between the first keyframe and the last keyframe, inclusive.
A contour is inactive before its first keyframe and after its last keyframe.

You do not need to define a matte for each frame. Defining a matte for some keyframes is sufficient to exclude the required area from the tracking process. MatchMover interpolates the matte in the frames between the keyframes.

You can apply several contours to the same image sequence, either at the same frame or at different frames.

The matte drawing workflow is described as follows:

Create and close a contour.
Create keyframes and interpolate the contour.
Edit the contour, if necessary.
Use several contours to mask areas of a sequence.
NoteBoth imported mattes and contours can be used at the same time.

Creating a new contour

When you draw a contour, the last point that was added or edited is the active point. For an open curve, the active point must be the last point of the curve. The active point is highlighted red.

To draw a new contour:

Do one of the following:
- Select Contour > New Contour.
- Click the New Contour icon in the Toolbar.
MatchMover enters the Contour Drawing mode, creates a new empty contour and selects it. The pointer changes to .

NoteTo exit the Contour Edition Mode, select any other element in the project (or press Esc).
Click in the Workspace where you want to begin drawing the contour. The newly created control point is added to the curve and it is then selected as the active point.
Click in the Workspace to add a second point to the contour. A new point is added to the contour and it becomes the active point.
NotePressing Del or Backspace deletes the active point.
Continue clicking in the Workspace until you have defined the contour you want.
If you have placed at least three points, do one of the following to close the contour:
- Press Enter
- Double-click the mouse button
- Hover the pointer over the first point of the contour. The pointer changes to . Click the mouse button.

A keyframe is created for the current contour and a new contour is added to the Contours folder in the Project window.

When you create a new contour, you create a new matte. The new matte is listed in the Project window as a child of the sequence to which it belongs.

In the Track window, contours are shown as children of the sequence mask.

The Track window shows for each contour:

Keyframes represented by a dark icon with a central black dot
Interpolated frames represented by a lighter color
Frames where this contour is not in use remain with the background color.

Selecting points and contours

In the Contour Drawing mode in the 2D View, you can select:

A contour by clicking on it in the Project window or the 2D View
A control point in a selected contour by clicking on it in the 2D View. The pointer changes to a nd the point becomes the active point.

When you select a contour in the Contour Drawing mode, it is represented by a thick outline and control points.

Other contours in the selected frame are represented by thin outlines and control points.

If the selected contour is inactive for the current frame, it is represented by a dashed line.

Inactive contours that are not selected are not displayed.

NoteWhile you are working on contours, the resulting matte is not shown in the 2D View, only the outline is displayed, even if matte display is turned off.

Changing a contour’s properties

The image below shows the contour’s Parameters window.

To rename the contour, change the name of the contour in the Label text field in the Parameters Window. The matte’s name is updated in the Image Sequences folder in the Project window.
The read-only text field Control points displays the number of vertices or control points for the contour.
Check the option Inverted to exclude the area outside the contour instead of excluding the one inside.
Check the Group attributes to specify a rigid moving object and set its corresponding sub-folder name.
Choose contour displayed color and use the slider to adjust the transparency.

Deleting a contour

Do one of the following:

Select a contour and either:
- Select Contour > Delete.
- Right-click in the 2D View and select Delete Contour from the pop-up menu.
- Press the Delete key.
Right-click the contour in the Image Sequences folder in the Project window or the Track window and select Delete Contour from the pop-up menu.

The selected contour is removed.

About keyframes and interpolating the contour

A keyframe is created for each closed contour. When you change the current time, the contour shown in the Workspace depends on the content of the contour at this frame.

If this is a keyframe, the contour for this keyframe is displayed.
If the contour is interpolated at this frame, the result of the interpolation is displayed.
Otherwise, the curve for the closest keyframe will be displayed.

Editing the curve at the current frame creates a new keyframe at the current frame and interpolates it between the other keyframe from which it was copied.

Adding a keyframe

To add a keyframe, do one of the following:

Select Contour > Add Keyframe.
Right-click in the 2D View and select Add Keyframe from the pop-up menu.

MatchMover creates a keyframe for the selected contour at the current frame using either the interpolated curve, if any, or the displayed curve.

If the new keyframe is between existing keyframes, then the interpolated curve is used. Otherwise a copy of the contour at the nearest keyframe is used. This ensures that the domain of definition of a contour is always an interval.

For example, a keyframe is defined at the time t0. When the time is changed to t1, the former curve is still displayed. When the curve is edited at t1, a new keyframe is created and interpolation of the curve will be performed between t0 and t1.

Deleting a keyframe

To delete a keyframe, do one of the following:

Select Contour > Remove Keyframe.
Right-click in the 2D View and select Remove Keyframe from the pop-up menu.

Editing a contour

Once you have created a contour, you can edit it to define the shape of your required matte.

Adding points to a contour

To add a new point to a contour, double-click anywhere on the selected contour.

The point is added for all keyframes of the contour.

Moving a point in a contour

To move a point in a contour:

Select a point so that it becomes the active point.
While holding down the pointer, drag the point to a new position.

Deleting a point from a contour

To delete a point from a contour:

Select a point so that it becomes the active point.
Do one of the following:
- Select Contour > Delete Point.
- Press the Backspace button on the keyboard.

The active point is removed from the contour and the preceding point becomes the active point. The point is deleted for all keyframes of the contour.

Moving the contour

To translate a contour:

Select a contour. See Selecting points and contours.
Click and drag the pointer anywhere in the 2D View.

The contour and its control points are translated and a keyframe is created at the current frame.

Rotating the contour

To rotate a contour:

Select a contour. See Selecting points and contours.
Press Shift+click. The pointer changes to . Drag the pointer anywhere in the 2D View.

This action rotates all the control points defining the current curve by a constant angle around a given 2D point, determined by the original position of the pointer at the time of the click, and creates a keyframe at the current frame.

Scaling the contour

To scale a contour:

Select a contour. See Selecting points and contours.
Press Ctrl+Alt+click. The pointer changes to . Drag the pointer horizontally in the 2D View.

The center of the scale is the original position of the pointer at the time of the click. The scale factor increases toward the right, decreases towards the left.

Copying and pasting a contour

You can copy and paste a contour at one keyframe only using the Copy and Paste commands.

To make a copy and paste a keyframe of a contour:

Do one of the following:
- Select a contour to duplicate and select Contour > Copy.
- Right-click in the 2D View and select Copy Contour from the pop-up menu.
- Right-click the contour in the Image Sequences folder in the Project window or the Track window and select Copy Contour from the pop-up menu.
MatchMover creates a copy of the contour at the current keyframe and stores it into a buffer.

NoteOnly one curve can be copied that way; if there is already a curve in the buffer, it is overwritten.
Select the contour and the frame where you will paste the contour frame as a new keyframe.
Select Contour > Paste.

Duplicating a contour

To duplicate all keyframes of a selected contour.

Select a contour then do one of the following:

Select Contour > Duplicate.
Right-click in the 2D View and select Duplicate Contour from the pop-up menu.

MatchMover creates an exact copy of the current contour featuring all keyframes. The contour is interpolated between this new keyframe and the existing ones.