Manual time sync data does not render

[parkermccoll]

Steps to reproduce:

• Load .fit file --> renders correctly
• Load .mp4 file --> couldn't auto-align warning
• Enter manual offset --> corrected video start overlaps with GPS range
• .fit data does not render

[Romancha]

Hi parkermccoll.

Thanks for the report. I need a bit more info to reproduce this:

1. GPStitch version (top-left next to the logo)
2. Video file — camera make/model, plus the output of:

   ffprobe -v error -show_entries format_tags=creation_time:stream=codec_type,width,height,duration <your.mp4>
   

3. Manual offset value you entered (in seconds or hours)
4. What "does not render" means exactly — does the render job fail with an error, complete with no overlay at all, or complete with the overlay but no telemetry values?
5. Screenshot of the Manual Offset panel after entering the offset (showing Corrected video start / GPS range)

Server log output from the terminal where you ran gpstitch during the render would also help a lot if you can grab it.

[parkermccoll]

Thanks for the quick reply!

1. v0.14.1
2. GoPro Max2, 8k 360, reframed to 4k mp4 using GoPro Quik

[STREAM]
codec_type=video
width=2160
height=3840
duration=34.966667
[/STREAM]
[STREAM]
codec_type=audio
duration=34.968005
[/STREAM]
[STREAM]
codec_type=data
duration=34.962000
[/STREAM]
[FORMAT]
TAG:creation_time=2026-04-10T17:46:54.000000Z
[/FORMAT]

3. Offset -63480 seconds
4. Overlay completes using video data (speed, map). No GPS data.

gpstitch terminal output.txt

[Romancha]

Thanks for the detailed info and screenshots!

A couple of clarifying questions:

1. Preview vs Render — when you say ".fit data does not render", do you mean the preview in the editor doesn't show .fit data, or that you started a full video render and the output video is missing .fit data? (The terminal log you attached doesn't show a render job being started, only preview generation.)

2. Which metrics are missing? — The preview screenshot shows speed (24) and a map with a route. Are these values correct for your ride? Your .fit file likely comes from a bike computer — does it contain metrics like heart rate, cadence, or power? If so, are those the values that are missing/showing as zero?

3. Did you try rendering the full video? If yes, could you share the terminal output from the moment you clicked the Render button?

What I found so far: Your reframed GoPro Max2 MP4 still contains embedded GoPro GPS data (I can see >> Found GPS9 in the logs). I've identified that the preview currently uses the video's embedded GPS instead of the .fit file when both are available — which would explain missing .fit-specific data. I'm working on a fix.