Struct DropFrameCalc 

pub struct DropFrameCalc;

Drop-frame timecode calculator for 29.97 fps.

29.97 fps = 30000/1001 fps. To keep timecode aligned with real time, 2 frame numbers are dropped per minute, except every 10th minute. Actual frame count per 24-hour day: 24 * 107892 = 2,589,408 frames.

Implementations

impl DropFrameCalc

pub fn frame_count_to_df(frame_count: u64) -> (u8, u8, u8, u8)

Convert a frame count to drop-frame timecode (hh, mm, ss, ff).

Uses the standard SMPTE drop-frame algorithm.

Reference algorithm (from SMPTE 12M): D = frame_count D_f = D + 2 * (D / 17982) + 2 * ((D % 17982 - 2) / 1798) [only if remainder >= 2]

pub fn df_to_frame_count(hh: u8, mm: u8, ss: u8, ff: u8) -> u64

Convert drop-frame timecode (hh, mm, ss, ff) to a frame count.

Standard SMPTE formula: frame_count = 108000hh + 1800mm + 30ss + ff - 2(total_minutes - total_minutes/10)

Note: 108000 = 30 * 3600 (raw 30fps hour count, NOT the drop-frame hour count).

pub fn format_df(frame_count: u64) -> String

Format a frame count as a drop-frame timecode string.

Drop-frame timecode uses semicolons (;) as separators.

pub fn parse_df(tc: &str) -> Option<u64>

Parse a drop-frame timecode string (HH;MM;SS;FF) into a frame count.

Returns None if the string is not a valid drop-frame timecode.

pub fn is_dropped_frame(hh: u8, mm: u8, ss: u8, ff: u8) -> bool

Check whether a given timecode position is a dropped frame number.

Frames 0 and 1 at the start of each minute (except multiples of 10) are dropped.