Editing Video and Audio Clips

You can trim the start and end of a clip, which is useful when you need to remove a portion of an asset for artistic reasons (such as a bumped camera). It is important to understand that video clips in DVD Studio Pro are trimmed based on GOP boundaries—you cannot choose a specific frame to trim to. The typical GOP (Group of Pictures) size for NTSC video is 15 frames—for PAL video it is 12 frames. This means you may have to choose between trimming a little too much or not quite enough. If you need to trim a clip precisely, you should use a video editor to make the trim, and then bring the asset back into DVD Studio Pro.

You can trim audio clips by frames, making it possible to trim off a popping noise.

Trimming can also be a way to use a small part of a longer asset. Only the part of the asset that is in the stream is included in the final disc size.

About the V1 Stream

The first video stream, V1, has requirements different from the other streams. DVD Studio Pro automatically ensures these conditions are met.

  • The first clip must be at the beginning of the timeline. There cannot be a gap between the timeline’s first frame and the first frame of the V1 clip. All other streams, including the other video streams, can have their first clip start anywhere in the timeline.

  • You cannot have gaps between clips in the V1 stream. All other streams can have gaps between their clips.

  • When building the project, the track ends at the last frame of video in the V1 stream. Any streams that have clips extending beyond the V1 clips are automatically truncated by the build process.

Trimming and Positioning Clips

There are several methods you can use to trim and position a stream’s clips within the Track Editor.

To trim a stream’s clip by dragging
  1. Position the pointer over the end of the clip you want to trim. The pointer changes to a bracket with an arrow pointing in the direction you can trim.

    Figure. Track Editor stream showing the trim bracket.
  2. Drag the clip’s edge to its new position.

Note: You cannot trim a clip beyond the edges of the asset.

To help guide you when trimming your clip, drag the playhead to the point you want to edit to. A vertical line appears across all streams, which you can use as a guide to trim an edge to. Be sure to use the timeline zoom feature to provide a close-up view of the area you’re editing.

Use care not to lose your video and audio synchronization when trimming. Instead of dragging, you can enter values in the Start and End boxes at the top of the Track Editor and the Duration and Clip Start Offset entries in the Clip Inspector to trim a clip more precisely so that you can repeat exactly the trim on other clips.

To use the start and end values to position and trim a clip
  1. Select the clip you want to trim. Its start and end values appear in the Track Editor’s Start and End boxes.

  2. Enter a new Start time. The beginning of the clip moves to that time.

    This moves the entire clip, but does not actually trim it.

  3. Enter a new End time. The end of the clip is trimmed to that time.

To use the Clip Inspector to trim a clip
  1. Select the clip you want to trim.

    The clip appears in the Clip Inspector.

  2. Enter a new Clip Start Offset to trim the clip’s start.

    The clip’s start position on the timeline is not changed—only its end position is moved to match its new duration.

  3. Enter a new Duration value to trim the clip’s end.

Clip Conflicts

There are a number of rules to keep in mind when you trim and position a clip.

Video Clips

Dragging clips to the V1 stream is different from dragging audio clips. In part this is due to the requirement that there can be no gaps in the V1 stream, and there must be a clip at its beginning.

The following situations cause video clips already in the V1 stream to move. This can cause problems if the video clips have associated audio or markers because they do not move with the video.

  • If you drag a video clip to the start of a V1 stream that already has a clip assigned: The new clip becomes the first clip and the original one (and any that follow it) shuffle down the timeline.
  • If you drag a video clip to the point where two existing video clips meet in a V1 stream: The new clip is inserted between them.
  • If you drag a video clip to the stream, and the “Find matching audio when dragging” preference setting is enabled: The audio in the A1 stream is trimmed or moved to accommodate the new video clip, even if that clip does not have matching audio. This maintains sync between the track’s existing video and audio clips.

Audio Clips

Because audio clips can be placed anywhere in their audio streams, the results are different from those you get when working with video clips.

  • If you drag an audio clip to any open area within an audio stream: The clip is placed there. If the open area is not long enough to hold the whole clip, the clip’s end is trimmed so that it will fit. Unlike video clips, audio clips do not move unless you move them intentionally.