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fix: Fix NDF LTC wall-clock time calculation

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Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>
This commit is contained in:
Chris Frankland-Wright 2025-08-05 20:59:19 +01:00
parent ed48c1284d
commit e4c49a1e78
1 changed files with 9 additions and 10 deletions
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19
src/system.rs
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@ -45,21 +45,20 @@ pub fn calculate_target_time(frame: &LtcFrame, config: &Config) -> DateTime<Loca
let timecode_secs =
frame.hours as i64 * 3600 + frame.minutes as i64 * 60 + frame.seconds as i64;
// Total duration in seconds as a rational number, including frames
let total_duration_secs =
Ratio::new(timecode_secs, 1) + Ratio::new(frame.frames as i64, 1) / frame.frame_rate;
// For non-drop-frame fractional rates (23.98, 29.97), timecode runs slower than wall clock.
// We need to scale the timecode duration up to get wall clock time.
// The scaling factor is 1001/1000. For drop-frame, this isn't necessary.
let scaled_duration_secs = if *frame.frame_rate.denom() == 1001 && !frame.is_drop_frame {
total_duration_secs * Ratio::new(1001, 1000)
// We must convert the entire timecode to a frame count using the nominal rate (e.g. 30),
// and then divide by the true fractional rate to get real wall-clock seconds.
// For integer rates or drop-frame, the components can be summed directly as they represent real time.
let total_duration_secs = if *frame.frame_rate.denom() == 1001 && !frame.is_drop_frame {
let nominal_rate = if *frame.frame_rate.numer() > 25000 { 30 } else { 24 }; // 30 for 29.97, 24 for 23.98
let total_frames = timecode_secs * nominal_rate + frame.frames as i64;
Ratio::new(total_frames, 1) / frame.frame_rate
} else {
total_duration_secs
Ratio::new(timecode_secs, 1) + Ratio::new(frame.frames as i64, 1) / frame.frame_rate
};
// Convert to milliseconds
let total_ms = (scaled_duration_secs * Ratio::new(1000, 1))
let total_ms = (total_duration_secs * Ratio::new(1000, 1))
.round()
.to_integer();