External videos - how to sync with data?

[pawliger]

I am using external GoPro videos. I have not found a reliable way to get data to match up with the video at the right time.

Say I have data for a lap that takes 1:00. I have 1:15 long video that has :05 of lead in, then the 1:00 for the lap, then :10 of extra.

When I add the video to the lap, I am asked to set the frame corresponding to the end of the lap. So I set it to 1:05 (I wish I could enter this as numbers as the scrollbar is not precise enough) But when I do this and generate an overlay the data in the overlay is off by about .5s. Note I do not change the intro or extro when rendering the overlay.

[Harry]

[Moved to Using LapTimer]

As starting the video recording requires a small amount of time (around 1 second) once LapTimer triggers a lap, this delay is always offset to video frame times. So if you sync manually, you need to take this into account. Instead of using the slider only, please try the small + and - minus buttons, they are designed to do the fine adjustment.

Before adjusting the sync point, please revert to your raw video first by selecting the lap from Lap List and pressing the Revert button. To re-adjust a sync point set, select the video Preview, scroll down to the lap associations and select the row representing your lap. This will open the sync dialog with your former sync point preserved.

- Harry

[pawliger]

So in my scenario, are you saying I should instead set the end time to 1:06 instead of 1:05?

Also, the Video Sync Setting dialog says to 'Select the frame matching the end of the timed lap'. But sometimes changing the time via the + and - buttons doesn't change the displayed frame. Should I assume the displayed time is used and the frame display is only approximate?

[pawliger]

One more issue: I processed the raw GoPro video with ffmpeg to produce a 720p .mp4 file as you suggested in another topic I posted previously.

I produced the overlay video and it seems to be OK though on my Nexus 5 the video doesn't play back smoothly - it has jumps in it. This whether I use the Gallery or Photos app to play back.

And when I transfer the overlay video file to my Mac I cannot play it back - I only hear audio and just see black, blank video.

[Harry]

One more issue: I processed the raw GoPro video with ffmpeg to produce a 720p .mp4 file as you suggested in another topic I posted previously.

I produced the overlay video and it seems to be OK though on my Nexus 5 the video doesn't play back smoothly - it has jumps in it. This whether I use the Gallery or Photos app to play back.

And when I transfer the overlay video file to my Mac I cannot play it back - I only hear audio and just see black, blank video.

Please try VLC on your Mac. It supports lots of decoders Quicktime does not support.

- Harry

[gplracerx]

The plus/minus buttons change the time in increments of 0.01 seconds. At 30 frames/sec, you need to change the time by 0.03 seconds, i.e. three button presses, to go to the next or previous frame and by 0.1 seconds or ten presses to change by three frames.

If you never plan to overlay internally recorded videos, you might want to change the Overlay Synchronization setting in Expert Settings to zero. Then you can select the exact frame when you sync a video.

Obligatory reminder: Don't mess with other Expert Settings unless you know what you're doing.