SMPTE 12M Linear Timecode synchronization for frame-accurate subtitle cueing in professional live productions.
Sub!t features a custom-built C++ native addon (subit-ltc-native) using CoreAudio for real-time LTC input from any audio interface. A JavaScript fallback mode with a full filter chain ensures broad compatibility across all setups.
Professional live events demand bulletproof timecode handling. Sub!t includes multiple layers of protection to ensure your subtitles stay in sync.
Extrapolates playhead from last known good TC during signal dropouts
Requires 4 consecutive incrementing frames before accepting TC baseline
Compensate timing differences between TC source and subtitle cues
Schmitt trigger filtering for clean zero-crossing detection
Automatically advance the GO output to the next file tab when the incoming timecode enters its designated range. When no tab matches the current TC range, the system falls back to sequential order—advancing to the next tab that contains cues.
Organize subtitles across multiple file tabs with different TC ranges. Sub!t automatically switches between them as the show progresses—hands-free operation during the performance.
Sync subtitles to the show's master timecode. Cues fire automatically at precise moments, eliminating manual operator errors.
Lock subtitles to LTC from your playback server or DAW. Load LTC audio files for offline programming and rehearsal.
Distribute the same LTC signal to multiple Sub!t instances for synchronized subtitle display across venues.