I've been having a pretty miserable time with various aspects of synchronisation over the last few weeks and thought I should get something down here for the benefit of future poor souls experiencing similar issues and searching the forum. The problems have been submitted as bug reports but I've heard nothing of any significance back.
Background: 64-bit Captivate 2019 running on good-standard i7 PC with loads of memory and decent graphics card.
Issue 1: I recorded several lengthy video demos, screen res 1280x720, set to generate smartshapes rather than captions, then later edited some of the text in the smartshapes and added audio to them as voiceover for the demo. When I publish as mp4 video, the audio is out of synchronisation with its associated smartshape by up to about three seconds. The workaround for this is to publish nothing longer than about seven minutes. As my videos were about twenty minutes, I ended up with three different seven-minute videos that I then joined together in either Camtasia or PowerDirector. Synch was then OK.
Issue 2. This is altogether more serious and cost me considerable time. I had e-learning containing videos that were set as web objects streaming from Vimeo, but wanted to incorporate these as local slide video and add some closed captions. The videos are mp4 format so I just insert video - slide video - 'from your computer' - 'progressive download' - show video on 'stage' - and 'modify slide duration to accommodate video'. The videos are then inserted and slide duration adjusted to incorporate them. Due to my previous experiences, everything was snipped up so there were no videos over about ten minutes duration, and mostly considerably shorter. This all worked fine with no apparent problems. So then, to add the closed captions, I select each video and click on 'Edit Video Timing'; then select the 'closed captioning' tab and start copying and pasting dialogue from my transcript. After a few minutes of video, if I went back to an earlier section, the captions would suddenly jump so that they were all about two seconds in advance of the video, getting worse further along the timeline. So I then move all the little yellow markers to the right to bring them back into synchronisation. (This isn't easy either, because every so often you're dragging the little yellow marker and it suddenly goes whizzing off to the right, ending up near the end of the video.) I ended up adding only three or four captions at a time, clicking OK, re-opening the Edit Video Timing dialogue, checking what I'd just done, correcting it if necessary, then adding three or four more. There seems to be no consistency with video length either, because sometimes this would only start happening several minutes into a video, then other times it would start immediately. So if anybody from Adobe reads this, I urge you to either (a) rebuild the Edit Video Timing/Closed Captioning tool from the ground up (I imagine it's all done with some kind of Flash code), or (b) allow us to add our own closed captions with something like Camtasia, and allow us to import them into Captivate as SRT files, which would be pretty foolproof as exact timings are specified in the file.