Replace Edit is a tricky feature to grasp at first, but is extremely powerful. I find it most useful in online editing, where I’m often replacing temporary footage with final, high resolution footage. The images are the same, but I can’t just recapture the footage with Batch Capture or Batch Import.

For instance, if I’m replacing stock footage, I often have to perform an “eye-match.” That’s where I choose a frame on the timeline as a reference, then find the corresponding frame in the high quality version. I want to replace the low quality version in the timeline with the final version. Without Replace Edit, this would be slow:

1. Copy any transitions on the timeline, because they will probably be lost when you overwrite and trim
2. Find matching frames with the playheads (so the source monitor looks like the record monitor)
3. In the sequence, mark from the matched frame to the end of the sequence
4. Overwrite that part of the clip with the new source
5. Put the playhead back on the cut where the matched frame is
6. Use Trim Mode to stretch the new source from the matched frame back to the beginning of the clip

Replace Edit is much easier:

1. Find matching frames in source and timeline with the playheads
2. Clear the in and out points on the timeline
3. Perform a Replace Edit

The footage in the timeline will be replaced with the source, starting at the matched frame and extending out to each nearest cut. Transitions will be maintained, but effects will be lost. If you want to keep your effects, step into them and perform the replacement there.

If you want, you can set in and out points on the timeline and Replace Edit will overwrite everything between the points. In and out points have no effect on the source side.