Captivate 2019 Closed Captioning Synchronization Slips

Report · Feb 22, 2022

Captivate has been pretty good for me in keeping audio and captioning synchronized - close enough that I haven't worried about the odd tenth of a second difference.

My current project is driving me nuts. I have gone through the closed captioning editing process three times now and every time I have had a series of captions that have slipped significantly - 2-3 seconds in come cases, 1 second most commonly. This throws everything off until it doesn't and the captioning is back in synch with the audio.

Yes, I am closing and saving the Captivate file between caption reviews, but that doesn't seem to help.

I am copying/pasting my captions from an ASCII text file, so I can't blame any errant Word artifacts.

Anyone have an idea about how to keep Captivate captions locked to where they are supposed to be?

Many thanks!

Don

Report · Feb 22, 2022

I have never encountered this particular issue. Like you I have found Captivate's CC synchronisation to be very reliable.

If this is only occurring in one particular CPTX project file then I would begin to assume that perhaps the project or one or more slides on it had become corrupted. If the issue is occurring on specific slides, try deleting those slides and inserting new ones rebuilt from scratch. Perhaps that will remove the glitch.

Report · Feb 23, 2022

Thanks, Rod;

Good thoughts, but this is the final stage of a very painful project, so rebuilding is not an option.

I thought perhaps I was doing the pause/copypaste routine too quickly, that maybe Captivate needed this sequence slowed down so it could get all the updates written before moving on. Slowing my inputs has not helped.

I will save to a new filename, and maybe that will help.

Note to Adobe: it wouldn't offend me in the least if Captivate could natively generate captioning. YouTube and TEAMS - unbelievably - can do this on the fly.

Report · Feb 23, 2022

Looks like this has been a problem for a while:

https://community.adobe.com/t5/captivate-discussions/captivate-2019-issue-with-closed-caption-sync-w...

Pat Smith posted that the issue arises when the vid does not start at time 0 but is delayed in the timeline, which is my set up. Irksome.

Report · Feb 23, 2022

Are you saying that there is complete silence for a period of several seconds on the slide BEFORE the audio begins? Are you using Text to Speech or normal human voiceover?

I would suggest you try adding some very low-level audio from the start of the slide timeline to the point where the audio begins. Even though this sound is so soft the user would not be able to hear it, Captivate will still detect it as sound. This might then mean your CC functions better.

Perhaps I have never encountered this CC synch issue because I always do my own voiceover and that always starts near the beginning of the slide timeline.

Report · Feb 24, 2022

Hi Rod,

Correct, there is about two seconds of silence at the beginning of the slide, that is where I have the titling. After that, the MP4 starts, at about the 2 second mark. The MP4 is a TEAMS meeting capture presentation that I am making pretty(er...).

It is the synching of the narration and the CC that is going amiss.

Owing to the length and complexity of this presentation, while it is possible to re-edit the MP4 and insert black for two seconds and start the vid at the 0 point is possible, rebuilding the CC would be a hassle I would like to avoid.

Text-to-speech is NOT being used... we have SOME standards here... not many, but some. I am synching the MP4 audio.

NOW, this is the first time I have run into this issue...but this is also the first time I have delayed the start of the vid to allow for titling that is NOT an integrated part of the vid.

Interesting notion about adding white noise.... have no idea how to do that since Captivate allows for just one audio track, however, right?

Report · Feb 24, 2022

Yes. Just one audio track allowed for the slide timeline. Though you can also add audio in the background as well as for individual objects, those clips are not able to be synched with the Closed Captioning.

If you have removed all audio for those initial seconds (perhaps by deleting it or adding silence) then maybe you can copy some audio from somewhere in the video where nothing is being said. Maybe a pause between paragraphs. Copy this audio into the silent area repeatedly to fill the hole and lower its volume so that it appears to be silent to the listenter.

Report · Feb 24, 2022

Ahhh.... edit the audio in situ... haven't tried that.

In any event, I DID edit a video that didn't have any play-pretties on it, and added two secs of blackscreen and then fades into the presentation. The CC still shifted on me. And the goofed part is, some slides are perfect, some have shifted. Im trying to find the common denominator here, but haven't yet.

'Preciate all your help and ideas, thank you!

Report · Feb 24, 2022

Sounding more and more like a corrupted project to me.

Report · Feb 24, 2022

Not sayin' it couldn't be.... this has been a very heavily-pounded on and tweaked effort.

Report · May 19, 2022

All, an update on my issue with closed captioning losing synch with the audio in a Captivate project.

To recap: In long TEAMS interview captures, the CC synchonization will slip, often by several seconds, and it takes repeated re-synching passes to get the CC and audio to remain remotely in time.

As was indicated by RobWard and others, two issues may be causing my issues, and I am cautiously optomistic that a workaround is reliable.

The TEAMS interview captures come in at 8 FPS but the Captivate project exports out at 30 FPS. This I think is the main source of my synch issues. Using Camtasia to re-render out at 30 FPS seems to help the synch, along with having the MP4 start at 0:00:00.

I did have the video start about 2 secs in to allow for fade-in and titling, but I am working that by a different method.

What I have found to be more of an irk is that with straight MP3 audio tracks, I see the ROW number in the CC editor that corresponds to the flags in the time window, but those ROW numbers are not displayed when doing CC work on an MP4. Irksome.

Report · May 19, 2022

The best way around this is the create an html page for the video and use a .vtt file for the captions.

The issue is that there are different timers at work here. The slide runs on a timer, the cc is on a timer and the video has it's own time. The slide timer doesn't wait for the video to load enough to begin playing. The timers end up getting out of synch.

When you do it with html the synch stays perfectly since the captions are listening to the video's timeupdate events.

Report · May 19, 2022

Hmmm.... well.... that is a few levels deeper to solve the issue than I was hoping for.

Thank you for the info!

Report · May 19, 2022

I agree that Dave's solution is probably the best, but if that's a bridge too far for you, here are some other suggestions:

The differences in the frame rate between Teams video and Captivate might not be the whole story. A lot of video is encoded with a Variable Frame Rate that increases the frame rate where action or movement is greater and reduces it where subjects are not moving as much. I have found that this can also affect synchronisation with audio, especially if you are lipsynching narration.

One free software app I use all the time to solve this is called Handbrake. I import the Variable Frame Rate video into Handbrake and re-render it out at Constant Frame Rate.

Also remember that audio can have variable or constant BIT rate, which is not the same as FRAME rate, but the principle is similar. Constant bit rate audio will stay in synch better with video, especially if they are both constant rate.

Perhaps you can test out whether re-encoding your video for constant frame rate and constant bit rate gives better results.

Report · May 20, 2022

Oh, SNAP! Handbrake, forgot all about that !!! Used it in the past but it has been a while.

Yes, I like this idea, thank you!!