Making the Best of a Bad Transition: Flow vs. Morph Cut

Posted on by Larry

Both Apple and Adobe released new transitions for their software recently that cause me real problems. Apple calls their’s “Flow,” and Premiere calls their’s “Morph Cut.”

The problem with both of these is that they make edits invisible. In today’s era of Fake News, both of these transitions can easily make it seem that someone has said or done something that they haven’t.

I’ve talked with both Apple and Adobe about this and both said, essentially, that creating Fake News was not their intent. Instead, they wanted to help filmmakers solve editing problems when they didn’t have enough coverage.

You can decide for yourself. Personally, I never use them and recommend against them.


Here’s a traditional edit, where we cut from a medium shot to a tight shot. It is enough of a change that the audience is not distracted by the change in angle. (Thanks to Dr. Vint Cerf for permission to use these clips.)

Here’s a traditional jump cut, where the size of the person in the frame does not change. Instead, they “jump” from one position to another. This unjustified movement is called a “jump cut” and clearly implies that an edit occurred. I don’t like jump cuts and avoid them where possible.

If a jump cut can’t be avoided, we would cover it with B-roll, which not only covers the jump but also indicates that edits were made to the of the speaker’s clip.

Now, we have a new option: the ability to blend between the two clips to make it look like no edit occurred. Here’s how these two transitions achieve their look.


When we have a jump cut, like the one above, we can now apply the Flow transition to the edit point. It is located in Transitions > Dissolves.

FCP X then uses optical flow technology to analyze and create new images for the transition, blending from the image at the Out to the image at the In.

As you can see in the sequence above, this blending can be effective at normal playback speed, but the individual frames look pretty weird. Optical Flow sometimes works great and sometimes it doesn’t.

The good news about this transition is that it requires no additional video in order to create its blended frames. The bad news is that this blending can create unusual, somewhat deformed images during the transition.

This transition works best when it is short, say 10 – 20 frames. The longer it lasts the stranger the results will look.


Adobe calls its transition Morph Cut – located in the Dissolve bin of the Effects panel.

This uses an entirely different system to create its invisible edit. Instead of creating new frames, it looks for other frames in the video that allow it to “morph,” or match, the movement it would take to create this transition in real-life.

His hands notwithstanding, this approach yields higher quality results, as you can see here.

The good news about this transition is that each individual frame is reasonably high quality. The bad news is that, for this transition to work the best, it needs lots of other frames in the video to pick from to build the morph.

Unlike the Flow transition, the Morph Cut can hold up well for longer periods, but, still, I would not extend it much past a second.


There are times where this effect can solve problems, especially in narrative fiction where we need to switch between shots and don’t have enough coverage to hide the edit.

However, those situations are relatively few in number compared to when we want to manipulate real-life. And, for that, these transitions can form a very slippery slope. They are nice to know about, but be very careful in using them.

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12 Responses to Making the Best of a Bad Transition: Flow vs. Morph Cut

  1. I agree that these are bad transitions.

  2. We documentary editors have always manipulated reality. We make people speak in coherent sentences, and say what they meant. I have made a person say ‘hundreds’ right on camera when she really said ‘thousands’. Before Flow, I could make a 4 frame or 8 frame dissolve easily enough. Flow is good for cutting out long pauses, but not for rewriting sentences. Frame size change is better in that case.

  3. Al Davis says:

    Larry: Although I have no argument for the potential to falsify narration with these tools; Morph Cut saved our production from a completely blown interview.
    We had a terrific interview with a non-talent expert. Although her content was terrific, she said UMMM between every thought. After reviewing in post, we realized this was so painful, it was unusable.
    Enter Morph Cut, and a gem of an interview. Exactly what she delivered with no annoying pauses. Nobody ever knew what we did it was so smooth. Even a re-shoot would not have solved the problem, because this was the best she was ever going to deliver. As with most non-talent interviews; It was more important to let her talk, and not break her thought continuity.

    Morph Cut used responsibly!

  4. Scott Pinzon says:

    ANY tool can be used for good or ill. Habitat for Humanity uses hammers; so do mentally ill serial killers. That doesn’t make hammers bad.

    Same for Morph Cut. I think your article does not sufficiently consider in-house corporate trainers, such as myself, who constantly use amateur spokespersons (I have written, produced, or directed more than 250 corporate videos, and have gotten to use professional actors approximately five times). When you have to record a lecture, there is only one camera, and the talent has no talent, Morph Cut becomes a life-saver.

    Perhaps your concern about “fake news” can be solved through making metadata more readily read. In the same way interested parties can see who edited a WikiLeaks article, maybe video sites need to reveal the where/when shot information stored with video footage.

    • Larry Jordan says:


      I’m enjoying reading all these comments, including yours. It is always good to expand our thinking.

      Thanks for taking the time to write.


  5. Philip Snyder says:

    As I wrote you several months ago, I had big problems getting an effective transition with Flow after I upgraded to OS 10.12 (Sierra). Prior to that with El Capitan, it did the job it was designed to do: bridging jumpcuts smoothly. Post upgrade, it would create a “freeze and release” effect looking like a bad cross dissolve. Other editors on Apple forums have reported this as well. I submitted to FCP X Feedback and discussed with Apple tech people. They asked me to do tests in both OS’s and submit them. I did back in February. So far, no response.

  6. I can remember a few situations where this dissolve would have saved me hours ….
    And for me video production is about having the audience get the point ….
    and ums and ahhs and other word crutches really get in the way of the communication.

    Thanks for all you do!

  7. Bernard Tagholm says:

    I’ve never used either of the transitions mentioned in the article, but I have used MorphCut from Motion VFX. In most cases it smoothly fixes an annoying jump cut, but if the jump covers too many frames the effects it produces can be more distracting than the jump. What it boils down to is how you use the tool. It can be a life saver when editing video with amateur talent when B-roll is not an option, providing a professional result. I’ve had many a nervous on-camera presenter thank me afterwards for making them look good. And even the weird effects created when covering long jumps can be useful when you need an eye catching effect, but they can also be over used. As I’m sure you’ll agree good editing judgement is paramount.

  8. Michael Munroe says:

    I had to remove a phrase just before the conclusion of the intro stand-up shot of the host in a project with English and Spanish versions today. Even with the camera locked down, I found that a quick cross dissolve was too obvious. I remembered your article and found that the Flow transition in FCP X did the job. I used a 7 frame transition in the English intro and a 15 frame transition in the Spanish intro. Fortunately, the host had kept his right hand in the same position and the result looks quite natural.

    And I do agree that this transition should be used sparingly. In this case though, it worked and saved quite a bit of effort and time that would have been involved in a re-shoot.

    Larry, thanks very much for posting this article.

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