Transcribe to Captions feature doesn't work within a compound clip. Is this expected behavior?

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Transcribe to Captions feature doesn't work within a compound clip. Is this expected behavior?

I ran into problems attempting to use the Transcribe to Captions feature of FCP X in a project. I'd select a clip, ctrl-click on it as specified in Apple's documentation, and attempt to select Transcribe to Captions. But that option was grayed out. Through some experimentation I determined that I'm unable to access the feature when working within a compound clip. This was true regardless of the audio source (imported, or recorded directly into FCP X using the VoiceOver recording feature).

However when the exact same audio clips are used directly in a project timeline, and not within a compound clip, the Transcribe to Captions feature can be selected and works as expected. I thought I'd post this here in hopes of saving someone else some trouble, as my web searches didn't turn up anything in the way of potential explanations. Anyone know if this is "working as designed" or a bug?

Note that the Transcribe to Captions feature is only available on Apple Silicon Macs. Apparently this is because FCP X does the transcription locally on the Mac, rather than sending it to the cloud as Adobe Premier and DaVinci resolve do.

Another tip: Once I got the feature working I found that some of the resulting captions would be marked in red. This turns out to mean FCP's detected a problem with the caption after transcription. With the caption selected, look in the inspector and you'll find a description of the problem at the bottom. In my case, it usually said the caption was too close to another and needed to be moved some number of frames.

MacBook Pro 16″, macOS 15.5

Posted on Aug 1, 2025 6:31 PM

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Answer 1

Top-ranking reply

Andre Molyneux Author

Level 1

29 points

Aug 2, 2025 7:34 AM in response to Luis Sequeira1

Luis,

Thanks for replying. Further experimentation shows that captions can exist within compound clips. But there are caveats:

Captions can only be created manually inside of a compound clip. Transcribe to Caption doesn't work.
Within the compound clip itself the captions are useless. They're grayed-out upon creation and cannot be enabled.
When the compound clip is used in a project timeline, the captions within the compound clip remain disabled.

However, they can serve a purpose. I found that when a compound clip containing captions is used in a project timeline, one of the selections presented when ctrl-clicking the compound clip is Extract Captions. Doing this copies the captions from within the compound clip to the project timeline, retaining in and out points, but now they're enabled and work as expected.

Extract Captions is covered in the FCP User Guide, in "Advanced Editing->Add, adjust, and share captions->Import captions". It's discussed in the "Import a media file with embedded CEA-608 captions" subsection, although compound clips aren't mentioned specifically.

I'm guessing it's done this way so there can't be a conflict between captions embedded in a compound clip (or imported media file) and those on the timeline. Only captions created in, or extracted to, the project timeline are enabled.

But since captions can be manually created within a compound clip, it leaves open the question as to why Transcribe to Caption is disabled there.

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Answer 2

Aug 2, 2025 7:45 AM in response to Andre Molyneux

Andre Molyneux wrote:

Luis,

Thanks for replying. Further experimentation shows that captions can• exist within compound clips. But there are caveats:

Captions can only be created manually inside of a compound clip. Transcribe to Caption doesn't work.

• Within the compound clip itself the captions are useless. They're grayed-out upon creation and cannot be enabled.

• When the compound clip is used in a project timeline, the captions within the compound clip remain disabled.

However, they can serve a purpose. I found that when a compound clip containing captions is used in a project timeline, one of the selections presented when ctrl-clicking the compound clip is Extract Captions. Doing this copies the captions from within the compound clip to the project timeline, retaining in and out points, but now they're enabled and work as expected.

Extract Captions is covered in the FCP User Guide, in "Advanced Editing->Add, adjust, and share captions->Import captions". It's discussed in the "Import a media file with embedded CEA-608 captions" subsection, although compound clips aren't mentioned specifically.

I'm guessing it's done this way so there can't be a conflict between captions embedded in a compound clip (or imported media file) and those on the timeline. Only captions created in, or extracted to, the project timeline are enabled.

But since captions can be manually created within a compound clip, it leaves open the question as to why Transcribe to Caption is disabled there.

Thank you. I stand corrected.

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Answer 3

Aug 2, 2025 2:28 AM in response to Andre Molyneux

You are right that it does only work in a project timeline, and for a very simple reason: captions only exist in projects, not clips (compound or otherwise).

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Answer 4

Aug 2, 2025 7:28 AM in response to LocaAlicia

LocaAlicia wrote:

Can you show us a screenshot of your caption settings? What format are you using?

The format is irrelevant, and it is also irrelevant that the OP was trying the Transcribe to Captions tool.

It would be the same if he tried to add captions manually.

Compound clips don't have captions, projects do.

So the solution if one wants captions is to put the compound in a project, and do Transcribe to Captions there.

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Answer 5

Aug 1, 2025 7:29 PM in response to Andre Molyneux

Can you show us a screenshot of your caption settings? What format are you using?

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Answer 6

Aug 2, 2025 11:28 PM in response to Andre Molyneux

it usually said the caption was too close to another and needed to be moved some number of frames.

If you change it from "CEA-608" to the standard "SRT", the warning should disappear, so could you try that?

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Answer 7

Aug 2, 2025 11:58 PM in response to LocaAlicia

LocaAlicia,

I'm using CEA-608 but I believe the behavior was the same with the default iTT captions before I switched formats. Are these the settings you're asking about?

[Edited by Moderator]

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