When to Edit Timing Manually

Global tools like the offset slider and linear drift calibration handle the majority of subtitle sync problems. Manual timing editing is needed for cases that global corrections cannot address:

• Individual cue errors: A specific subtitle appears too briefly or lingers too long while all others are fine.
• Segmented desync: A scene is added or removed in the middle of the video, shifting all subsequent cues. This creates a breakpoint that requires editing each segment separately.
• Overlapping cues: Two consecutive subtitles overlap in time, causing both to appear on screen simultaneously.
• Reading time optimization: A subtitle with dense text needs longer display duration, while a short one-word line can be shortened.
• Fine-tuning after global correction: After applying offset or drift calibration, individual cues near scene transitions may need minor adjustments.

SyncFlow combines global and manual editing in one interface, so you can apply a broad correction first and then fine-tune individual cues without switching tools.

Using the Inline Editor

The Cues Registry displays every subtitle cue with its number, start time, end time, and text. Each field is editable in place.

The inline editor is the fastest way to fix a small number of cues. For larger batches of adjustments, the waveform editor provides visual control.

Waveform Cue Editing

The waveform preview displays the audio waveform of your video with subtitle cue markers overlaid. Each cue appears as a colored bar spanning from its start time to its end time.

The waveform editor provides visual context for timing decisions. You can see where speech starts and ends in the audio waveform, making it easier to align cue boundaries precisely with spoken dialogue. This is especially useful for adjusting subtitle duration to match natural speech pauses.

Split and Merge Cues

Splitting a Cue

Splitting divides one subtitle cue into two at the current playhead position. This is useful when a single subtitle contains two lines of dialogue that should appear as separate timed cues, or when a scene change occurs mid-cue.

• Place the playhead at the split point.
• Select the cue to split.
• Click Split Cue. The original cue ends at the split point, and a new cue starts at the split point and continues to the original end time.
• Edit the text of each resulting cue as needed.

Merging Cues

Merging combines two consecutive cues into one. This is useful when short adjacent subtitles would read better as a single line.

• Select two consecutive cues in the Cues Registry (Shift+click for range selection).
• Click Merge Cues. The text of both cues is combined, and the timing spans from the first cue's start to the second cue's end.
• Edit the combined text to remove any redundancy.

Both operations maintain the gap between the merged/split cue and its neighbors. The undo history records each operation separately, so you can revert split or merge without affecting other edits.

Keyboard Shortcuts for Editing

SyncFlow provides keyboard shortcuts for efficient editing without leaving the video player context:

These shortcuts work across all editing modes — offset adjustment, inline text editing, and cue selection. They are designed to minimize context switching during the editing workflow.

Undo and History

SyncFlow maintains a full undo history for every editing action. Every change — offset adjustment, drift calibration, inline timestamp edit, text change, split, merge — is recorded as a separate entry in the history.

Press Ctrl+Z to step backward through the history one action at a time. The undo is unlimited, so you can revert any number of changes back to the original file state. Press Ctrl+Shift+Z to redo any undone action.

The undo history is preserved in the .syncflow project file. If you save a project, reload it later, and continue editing, the undo history from the previous session is available alongside new edits.

Verification Best Practices

After manual editing, verify your work systematically:

1. Check for overlaps: Review the Cues Registry for any cues with overlapping time ranges. SyncFlow highlights overlapping cues visually.
2. Check reading time: Ensure each subtitle stays on screen long enough to be read comfortably. A common rule is at least 1 second for short cues and 3-4 seconds for a full line of text.
3. Play through edited sections: Use the A-B loop to play back each edited section at full speed. Verify that each cue appears and disappears at the correct moment relative to the dialogue.
4. Export and test: Download the corrected file and load it into your media player (VLC, Plex, etc.) for final verification. Different players may handle edge-case timestamps slightly differently.

For an overview of all sync correction methods available in SyncFlow, see the complete guide to fixing out-of-sync subtitles.