10.9 Timeline Display: Negative Timecodes
Your project settings includes an option to set project start time.
Kind: concept (user-guide-section) Chapter: 10 Pitch and Time Manipulation Source: REAPER User Guide v7.70
Your project settings includes an option to set project start time. Negative timecodes will be shown on the REAPER timeline/ruler before the project start time if that start time (00:00:00.00) is set to some time into the project. For example, 10 seconds before project time zero is displayed as -01:59:50:00 because that position is in hour number -1, the first hour to the left of zero, and that position is 59:50:00 into that hour. Every element of the timecode runs forwards, but the hour field is allowed to be negative so it runs ...-2,1,0,1,2,... . In DF timecode mode frames are dropped predictably at the start of every minute that is not divisible by 10. There is a consistent number of frames between any two H:M:S:F positions that have the same relative difference between any two elements, for example -01:57:00:02 to 00:00:00:00 is the same number of frames as 00:57:00:02 to 01:00:00:00.