Variable type to hold timecode values representing video frames. This may be a
position or a duration (length).
Note it is *signed* long to allow negative values -
The max range of unsigned long is
LONG_MAX 2147483647 Maximum (signed) long value
LONG_MIN -2147483647-1 Minimum (signed) long value
This is plenty to handle the maximum number for frames in a 24 hour working
period, which is 24*60*60*30 == 2592000
See MXOMF_NOTTC
typedef signed long MXOMF_TIMECODE;