Canon EOS 5D Mark III Instruction Manual (en)

 Setting the Time Code
You can select what to display on the movie-shooting screen.
[Rec time]
: Indicates the elapsed time from the start of the movie 
[Time code] : Indicates the time code during movie shooting.
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.
Movie Recording Count
Movie Playback Count
Shooting still photos during movie shooting will cause a discrepancy 
between the actual time and time code.
Regardless of the [Movie rec count] setting, the time code will always be 
recorded to the movie file.
During movie shooting
During movie playback
With [Time code] set:
If you change the setting for either [Movie play count] in [z5 (movie): 
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.