Canon EOS 6D Instruction Manual page 221

Shooting still photos during movie shooting will cause a discrepancy
between the actual time and time code.
If [Free run] is set and you change the time, zone, or daylight saving
time (p.36), the time code will be affected.
The time code is not recorded for video snapshots.
Regardless of the [Movie rec count] setting, the time code will always be
recorded to the movie file.
Movie Playback Count
You can select what to display on the movie playback screen.
[Rec time] : Displays the recording time and playback time during
movie playback.
[Time code] : Displays the time code during movie playback.
With [Time code] set:
During movie shooting
If you change the setting for either [Movie play count] in [Z2: Time
code] or for [x3: Movie play count], the other setting will also change
automatically.
"Frames" are not displayed during movie shooting and movie playback.
3 Setting the Time Code
During movie playback
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