video-editing

name	video-editing
description	Video editing decisions: what to cut vs keep, cut techniques (J-cut, L-cut, hard cut), pacing by format, edit decision structure, silence/filler removal, talking head editing. Use when making editorial decisions about video content. Keywords: video editing, cut, trim, j-cut, l-cut, pacing, filler words, silence, talking head, edit decision, transition, dead air, false start

Video Editing — Editorial Decisions

What to Cut

1. Filler words: "um", "uh", "like", "you know" — cut at word boundaries using word timestamps
2. False starts: When the speaker restarts a sentence, keep only the final take
3. Dead air: Silence longer than 1.5 seconds should be trimmed to ~0.5 seconds
4. Off-topic tangents: If the speaker wanders, cut to the next relevant segment
5. Repeated points: Keep the best delivery, remove redundant takes

What NOT to Cut

• Breath pauses: Natural 0.3-0.8 second pauses between sentences. These sound natural.
• Emphasis pauses: Intentional pauses for dramatic effect
• Reactions and transitions: Verbal bridges like "So..." or "Now..." that provide flow

Cut Techniques

Technique	Description	When to Use
J-cut	Audio from next segment starts ~0.5s before visual cut	Smooth transitions
L-cut	Audio from current segment continues ~0.5s after visual cut	Maintaining continuity
Hard cut	Instant transition	Major topic changes
Jump cut	Cut within same shot (visible jump)	YouTube/social energy, pacing
Match cut	Visual similarity bridges two different shots	Creative storytelling

Pacing by Format

Format	Approach
Short-form (< 60s)	Aggressive cuts. Minimal dead air. High energy. Visual change every 1-3s
Medium-form (1-10 min)	Balanced. Keep natural pauses for breathing room. Change every 3-5s
Long-form (> 10 min)	Let scenes breathe. Only cut obvious problems. Change every 5-10s

Edit Decision Structure

When planning an edit, define:

• Cuts: Ordered list of segments to keep (source, in/out points, speed)
• Overlays: Timed overlay placements (images, diagrams, lower thirds)
• Subtitles: Subtitle configuration (enabled, style, source file)
• Music: Background music settings (asset, volume, ducking, fades)
• Transitions: Transition type and timing between cuts

Silence Removal Workflow

1. Detect silence with FFmpeg: silencedetect=noise=-35dB:d=0.4
2. Parse silence_start/silence_end timestamps from stderr
3. Generate segments of non-silent audio
4. Concatenate segments with the concat demuxer
5. Optional: apply atempo=1.14 for subtle speedup that feels natural

Talking Head Editing Checklist

• No visible jump cuts without intentional style choice
• Audio doesn't pop or click at cut points
• Pacing matches content energy and target platform
• Speaker's face is never covered by overlays
• All cuts are at word boundaries (not mid-word)
• Filler words removed unless they serve the personality
• B-roll covers any remaining jump cuts

Lip Sync (Dubbing / Localization)

When replacing audio and matching lips:

Input	Tool	Output
Existing VIDEO + new audio	Lip sync	Video with synced lips
Still PHOTO + audio	Talking head generator	New video from photo

Decision rule: If you have video footage of the person, use lip sync. If you only have a photo, use talking head generation.

Workflow for localization:

transcribe(video) → translate → TTS(translated text) → lip_sync(original_video, new_audio)

Keep original video as source for each language — never chain lip sync outputs.

Face padding for lip sync: [0, 10, 0, 0] (top, bottom, left, right) works for 90% of footage. Increase bottom if chin gets cropped.

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Kolbo MCP Integration

Task	Kolbo MCP Tool	Notes
Transcribe for edit points	transcribe_audio	Word-level timestamps for precise cuts
Lip sync dubbing	generate_lipsync	Source video + new audio
Generate B-roll	generate_video or generate_image	Cover jump cuts
Generate narration	generate_speech	Re-record with AI voice
Visual analysis	chat_send_message + Gemini	"Analyze this video for edit points"

Editing workflow with Kolbo:

1. transcribe_audio → get full transcript with word timestamps
2. Identify filler words, dead air, false starts from transcript
3. Generate FFmpeg trim commands for non-silent/non-filler segments
4. generate_image or generate_video → B-roll for covering jump cuts
5. Concatenate clips + burn-in subtitles + mix audio
6. Review with production-review skill

Localization workflow:

1. transcribe_audio → source language transcript
2. Translate the transcript (use chat_send_message for translation)
3. generate_speech → TTS in target language
4. generate_lipsync → sync new audio to original face
5. Repeat for each language (always from original, never chain)

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Local / Free Options

IMPORTANT: Always use Kolbo MCP tools by default (transcribe_audio, generate_lipsync). FFmpeg silence removal is safe to use directly. For anything else, confirm with the user first.

FFmpeg (safe, standard): Silence detection/removal, trimming, concatenation — all built-in.

Transcription: If the user wants offline, faster-whisper runs on CPU (pip install faster-whisper). Confirm before installing.