Trimming

With some edits on the timeline it is possible to do trimming. By trimming you shrink or grow the edit boundaries (head or tail) by dragging them. In drag and drop mode or cut and paste mode, move the cursor over an edit boundary until it changes shape. The drag handle shows as a left or right facing fat arrow when you cursor near the clip start or end. If the cursor faces left, the dragging operation affects the beginning of the edit. If the cursor faces right, the dragging operation affects the end of the edit.

The effect of each drag operation not only depends on the behavior button but whether the beginning or end of the edit is being dragged. When you release the mouse button, the trimming operation is performed.

For all file formats, other than still images, the extent of the trimming operation is limited to the source file length. Attempting to drag the start of the edit beyond the start of the source, limits it to the source start. In all trimming operations, all edits which start on the same position as the cursor when the drag operation begins are affected. You have to disarm tracks in order to prevent edits from being affected.

You have 6 different choices of which mouse button to use for specific types of editing while using the drag handle. You change the drag handle mouse effects by using the Settings → Preferences → Interface tab and modifying the Editing section as shown in the next figure 6.3. The drag handle affects not only the clip you are working on but also frequently the entire duration of all clips on the timeline.

Figure 6.3: Default choices for mouse: Ripple for LMB; Roll for MMB; Slip for RMB

A description of the fundamental/common terminology for choices follows.

All Edits (ripple)

shorten or lengthen the start or end of a single piece of media while moving all media to the right of that clip up or down on the timeline correspondingly. Timeline duration is modified. In a drag All Edits operation, the beginning of the edit either cuts data from the edit if you move it forward or pastes new data from before the edit if you move it backward. The end of the edit pastes data into the edit if you move it forward or cuts data from the end of the edit if you move it backward. All the following edits shift. If you drag the end of the edit past the start of the edit, the edit is deleted.

One Edit (roll)

move the in and out point of a single clip without changing the timeline duration. In a drag One Edit operation, nothing is cut or pasted. If you move the beginning or end of the edit forward, the source reference in the edit shifts forward. If you move the beginning or end of the edit backward, the source reference shifts backward. The edit remains in the same spot in the timeline but the source shifts.

Src Only (slip)

move the in and out point of a single clip without changing the timeline duration. In a drag Src Only operation, nothing is cut or pasted. If you move the beginning or end of the edit forward, the source reference in the edit shifts forward. If you move the beginning or end of the edit backward, the source reference shifts backward. The edit remains in the same spot in the timeline but the source shifts.

Slide

a single clip is moved but retains its current in and out point; however the out point of the clip to the left changes and the in point of the clip to the right also changes. Timeline duration remains the same.

Edge Left/Right

moves the edge of the clips.

No effect

no changes are made. You might want to use this choice to prevent accidental movements.

NOTE:

you cannot do Trim operations on Hard Edges, which are produced by a cut operation ("x"). To create a cut useful for trimming you must select an interval (at the limit of one frame) to be muted ("m"); now the edges of the edits will be trimmable because they are not Hard Edges. See 5.4, Split - blade cut and hard edges.

The next table displays the options and results with the Key Table here first.

s = src media start
p = proj position
l = length
c = cut distance
rest == p+=c: for rest of clips
01 = flags edits_moved, rest_moved

		Drag Left	Drag Right
curr s += c, l -= c; + rest		←	→	rest
abc12345xyz	Ripple left edge 11 →	abc012345xyz	abc2345xyz
curr l += c; + rest		←	→	rest
abc12345xyz	Ripple right edge 01 →	abc1234xyz	abc123456xyz
prev l += c; curr ps+= c, l -= c		←	→
abc12345xyz	Roll left edge 00 →	ab012345xyz	abcd2345xyz
curr l += c; next ps+= c, l -= c		←	→
abc12345xyz	Roll right edge 00 →	abc1234wxyz	abc123456yz
s -= c		←	→
abc12345xyz	Slip left edge 10 →	abc23456xyz	abc01234xyz
s -= c		←	→
abc12345xyz	Slip right edge 10 →	abc23456xyz	abc01234xyz
prev l += c; curr p+= c; next ps += c, l -= c		←	→
abc12345xyz	Slide left edge 10 →	ab012345wxyz	abcd12345yz
prev l += c; curr p+= c; next ps += c, l -= c		←	→
abc12345xyz	Slide right edge 10 →	ab12345wxyz	abcd12345yz
curr s -+= c, l += c; + rest		←	→	rest
abc12345xyz	Edge left edge 11 →	abc2345xyz	abc0123456xyz
curr l -+= c; + rest		←	→	rest
abc12345xyz	Edge right edge 01 →	abc1234xyz	abc123456xyz

Next, a more immediate and colorful view shows these trimming options (figure 6.4).

Figure 6.4: The 5 types of Trim: note the different lengths of the results.

How to do a J-cut or L-cut

A J-cut is a split edit film editing technique in which the audio from a following scene overlaps the picture from the preceding scene, so that the audio portion of the later scene starts playing before its picture as a lead-in to the visual cut. An L-cut is a different split edit film editing technique in which the audio from preceding scene overlaps the picture from the following scene, so that the audio cuts after the picture, and continues playing over the beginning of the next scene (figure 6.5). To do either a J-cut or an L-cut, you first shorten the first or second video a little. Then you block the audio tracks from changing by disarming the appropriate tracks. Finally use One Edit (roll) the cutting edge off the videos. Moving to the right creates a J-cut and moving to the left creates an L-cut.

Figure 6.5: J-cut to left and L-cut to right