1Understanding SMPTE Timecode
SMPTE timecode (Society of Motion Picture and Television Engineers) provides a standardized way to identify each frame of video or film. Originally developed for television broadcast, timecode has become essential for synchronizing audio and video in post-production, live events, and any multimedia work requiring frame-accurate alignment.
For audio professionals, timecode bridges the gap between musical time and video time. Film composers score to timecode. Sound designers sync effects to specific frames. Post-production mixers deliver audio that aligns perfectly with picture. Understanding timecode is essential for anyone working with music and video together.
Our timecode calculator converts between SMPTE timecode and other useful formats including total frames, seconds, milliseconds, and audio samples. This enables precise translation between video-world timing and audio-world timing.
2The Timecode Format
Timecode displays as HH:MM:SS:FF—hours, minutes, seconds, and frames. Unlike a simple clock, the final digits represent frame count rather than fractions of a second. At 30 frames per second, frame 00 through frame 29 occur within each second before rolling to the next second.
Reading Timecode: 01:23:45:15 means 1 hour, 23 minutes, 45 seconds, and 15 frames into that second. At 30fps, frame 15 occurs exactly halfway through second 45. The total elapsed time is approximately 1 hour, 23 minutes, and 45.5 seconds.
The frame count resets with each second, similar to how seconds reset with each minute. Maximum frame values depend on frame rate—29 for 30fps, 24 for 25fps, and so on. Frame 00 is the first frame of each second.
3Frame Rate Standards
Different video standards use different frame rates. Film traditionally uses 24 frames per second (fps). PAL television (Europe, Australia) uses 25fps. NTSC television (North America, Japan) uses 29.97fps. Modern digital video often uses 30fps or 60fps.
The frame rate affects timecode-to-time conversion. One hour of timecode at 24fps equals exactly 86,400 frames (24 × 60 × 60). At 30fps, one hour equals 108,000 frames. Our calculator accounts for frame rate when converting between timecode and real time.
Choosing the wrong frame rate causes sync errors that accumulate over time. A one-hour program timed at 30fps but played at 29.97fps drifts by 3.6 seconds. Always confirm frame rate before beginning any timecode-dependent work.
4Drop Frame Timecode
The 29.97fps NTSC frame rate creates a problem: timecode counted at exactly 30fps drifts from real time. A one-hour show displayed as 01:00:00:00 in non-drop timecode actually runs 3.6 seconds longer than a real hour. Drop frame timecode solves this by periodically skipping frame numbers.
Drop frame skips frames 00 and 01 at the start of each minute, except every tenth minute. No actual video frames are dropped—only the numbers are skipped to keep timecode aligned with clock time. Drop frame timecode uses semicolons (01:00:00;00) instead of colons to indicate this mode.
Use drop frame for broadcast content that must match real-time duration. Use non-drop for film-originated content or when frame count accuracy matters more than real-time alignment. Our calculator supports both modes and shows the difference in total frames.
5Audio and Video Synchronization
Audio sample position must align with video frame position for proper sync. At 48kHz audio and 30fps video, each frame spans exactly 1,600 samples (48,000 ÷ 30). Our calculator converts timecode directly to sample position, enabling precise audio placement against picture.
DAWs with video import typically lock to timecode automatically. Understanding the underlying math helps troubleshoot sync issues. If audio and video drift apart, check that both use the same frame rate and that sample rate conversion hasn't introduced errors.
For frame-accurate audio editing, calculate the sample position of each frame boundary. If a sound effect must hit exactly on frame 01:15:30:12, multiply total frames by samples-per-frame to find the exact sample location in your audio timeline.
Our delay time calculator helps with sync-related timing, while the sample length calculator converts between samples and time for audio-specific measurements.
6Converting Between Formats
Total frames from timecode: (hours × 3600 + minutes × 60 + seconds) × frame_rate + frames. This converts timecode to an absolute frame count useful for calculations. At 30fps, 00:01:00:00 equals 1,800 frames.
Seconds from frames: frame_count ÷ frame_rate. At 24fps, 2,400 frames equals exactly 100 seconds. Non-integer frame rates like 29.97 require careful handling—use the exact rate, not 30, for accurate conversion.
Milliseconds provide useful precision for audio work. Our calculator shows millisecond equivalents for any timecode, enabling comparison with audio timing specifications that use milliseconds rather than frames.
Sample position for audio requires knowing both frame count and audio sample rate. The calculator assumes 48kHz (professional video standard) but the formula works for any rate: samples = seconds × sample_rate.
7Post-Production Audio Workflow
Film scoring typically begins with importing video and locking the DAW to its timecode. The composer sees timecode in the timeline and can spot music cues to specific frame locations. Hit points—moments where music emphasizes on-screen action—are specified in timecode.
Sound design works similarly. A door slam at 00:45:23:08 must be placed precisely at that frame's audio sample position. The calculator converts this timecode to samples for exact placement in any DAW.
Audio delivery for video requires understanding technical specifications. Broadcast often requires audio starting at 01:00:00:00 timecode with specific pre-roll. Knowing frame-to-sample relationships ensures delivered audio aligns correctly with picture.
8Professional Tips
Always document frame rate for every project. Label sessions clearly with frame rate. Confusion between 29.97 and 30 causes subtle but accumulating sync errors that may not be obvious until the end of a long program.
When receiving video for audio work, verify timecode and frame rate before beginning. Import a short section and check sync before committing to full production. Five minutes of verification saves hours of correction later.
Keep a timecode calculator accessible—on your phone, bookmarked in your browser, or as a desktop utility. Quick conversions during sessions prevent workflow interruptions and ensure accurate decisions.
For tempo-synced work within video projects, our frame rate to BPM calculator shows tempos that align perfectly with frame boundaries, eliminating drift between musical beats and video frames.