“Aaaaarg – the timecode on my source clips doesn’t match the actual time they were shot!”

If your camera date/time was accurate, you can fix the timecode by transcoding the source files based on their actual creation time (as saved to your SD/XQD/SSD card in-camera). You’ll need to run some scripts. This solution is from a macOS POV. Fix your timecode to match the real time (in macOS) below.

 

 

Without correct time-based timecode – clips will only import as a continous sequence
Working on the script with ChatGPT
The script to update timecode, nicely formatted in Xcode
Once timecodes are fixed the clips can be added to the timeline in by time of shot
Correct your Timecode settings in-camera so you don’t have to faff about with all this scripting nonsense.

 

 

Why is the Timecode goofy?

When editing my first multi-camera shoot, I found that the timecode in the recorded files did not match real time, despite Timecode Origin being set to Current Time in both of my [Nikon Z] cameras. So, laying out clips on the timeline and syncing them with the separate audio track was a real PITA.

By default, on my Nikon Z cameras, Record Timecode is off. When turned on, Timecode Origin is set to Current Time. Sounds great, yeah?

But the default Timecode Count-up method is set to [Record run], meaning timecode only increments when recording. So, if you stop recording at midday for a break of 2 hours, 13 minutes, and 53 seconds, the next shot will start back at midday (+ 1 frame) rather than the actual time.

To ensure your timecode reflects real time in each clip, you must set Timecode Count-up to [Free run] in your camera settings. Nikon Z 8 Timecode Settings.

How to fix (to the nearest second)

While staring morosely at the folder with my source clips, I noticed the file creation dates were accurate.

So, off to ChatGPT I went, and after an hour of trial and error, I had a working solution. It was much quicker and more accurate than manually editing the timecode in DaVinci Resolve.

Solution

Using basic scripting, we can re-encode the source files with new timecode metadata based on the modification date. This requires FFmpeg (installed via Homebrew).

Fixing Timecode to Match Real Time (macOS)

1. Install Homebrew & FFmpeg

First, install Homebrew (if you don’t have it yet). Open Terminal (search “Terminal” in Spotlight) and paste:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

Once installed, add FFmpeg by running:

brew install ffmpeg

2. Duplicate and Navigate to Your Video Files

  1. Duplicate your source video folder (the script rewrites the new files over the old ones – by design). Make a backup first!
  2. Open the Terminal application
  3. Type cd (with a space after cd)
  4. Drag & drop the folder with your video files into the Terminal window
  5. Press Enter

💡 Tip: This saves you from manually typing the file path!

3. Save & Run the Fix-Timecode Script

A. Create the Script

  1. Open TextEdit
  2. Click Format > Make Plain Text
  3. Copy & paste the following script:
#!/bin/bash

for file in *.MOV; do
    echo "Processing: $file"

    # Extract existing timecode (for reference)
    existing_tc=$(ffmpeg -i "$file" 2>&1 | grep -o 'timecode [0-9:]*' | awk '{print $2}')
    echo "  Existing Timecode: $existing_tc"

    # Extract file creation time
    creation_time=$(mdls -raw -name kMDItemContentCreationDate "$file" | tr -d 'Z')

    # Extract frame rate (detects 25fps or 50fps)
    fps=$(ffprobe -v error -select_streams v -show_entries stream=r_frame_rate -of csv=p=0 "$file" | awk -F'/' '{print $1/$2}')
    if [[ "$fps" == "25" ]]; then
        timecode_format="HH:MM:SS:FF"
    else
        timecode_format="HH:MM:SS;FF"  # Drop-frame notation for 50fps
    fi
    echo "  Detected FPS: $fps ($timecode_format format)"

    # Convert creation time to HH:MM:SS
    timecode=$(date -j -f "%Y-%m-%d %H:%M:%S %z" "$creation_time +0000" "+%H:%M:%S:00")

    # Use a temporary file to modify metadata
    temp_file="temp_$file"

    ffmpeg -i "$file" -c copy -timecode "$timecode" "$temp_file"

    # Replace original file with updated file
    if [[ -f "$temp_file" ]]; then
        mv "$temp_file" "$file"
        echo "  Updated Timecode: $timecode"
    else
        echo "  Error updating $file"
    fi
done
  1. Click File > Save
  2. Name it fix_timecode.sh (ensure it has the .sh extension)
  3. Save it in the same folder as your video files

B. Make the Script Executable

Back in Terminal, navigate to your video folder again (cd [drag & drop folder]).
Then make the script executable by running:

chmod +x fix_timecode.sh

C. Run the Script

Now, execute the script with:

./fix_timecode.sh

✅ What Happens?

  • The script reads the creation timestamp from each file
  • It detects the frame rate (25fps or 50fps)
  • It applies the correct timecode format
  • It updates each file’s timecode without re-encoding

 

⚠️ Caveats & Notes

  • Your camera clock must have been set correctly when recording
  • Camera clock accuracy drifts over time – sync your cameras soon before the shoot.
  • Filesystem timestamps may not have sub-second precision, so fine-tuning might still be needed
  • Drop Frame vs. Non-Drop Frame is not covered here.
  • Timecode only spans 24 hours, so multi-day shoots need additional tagging/grouping.