Editing > Working With Containers, Matte Containers and Multi-channel Clips > About Multi-channel Clips >

# Edit the Timing of a Matte in a Multi-Channel Clip to Match the Source Clip

Timing modifications done inside a multi-channel segment are saved in the source clip in the library. All instances of that source clip are updated to use the new timing.

You can only slip a shot to adjust its timing. You cannot trim.

To protect the structure of the source footage, it is not possible to add dissolves or layers inside the multi-channel clip. Use matte containers for more complex editing.

To create a temporary grade to help you set the timing of a matte in a multi-channel clip:

1. Exit the multi-channel clip on the timeline.
2. Enable a Secondary.
3. Enable one of the External Matte channels (R/G/B/A).
4. Modify the grading so that you can see the matte media over the image.
5. From the Timeline menu, enter the multi-channel clip.
6. Slide the clip in the timeline to change the timing. Use the display of the matte over the shot to help you find the right starting frame.
7. Click the Up arrow to exit the multi-channel segment. You are now ready to grade your shot.