cut-silences

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Agent 1 of the video editing pipeline. Removes silences and dead air from a talking-head recording. Use when asked to cut silences, trim pauses, remove dead air / gaps, or tighten the pacing of a raw video, given a word-level transcript. Produces an edit list (EDL), a re-timed transcript for downstream agents, and optionally the cut video via ffmpeg. Does NOT cut mistakes, repeats, or false starts — that is the cut-mistakes agent.

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Sourcenateherkai/hyperframes-student-kit

Added on2026-10-14

NPX Install

npx skill4agent add nateherkai/hyperframes-student-kit cut-silences

SKILL.md Content

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Cut Silences (Pipeline Agent 1)

First step of the automated edit. Takes a raw recording + its word-level transcript and removes only silence: dead air before the first word and after the last word, plus inter-word pauses longer than a threshold (trimmed down to a natural breath, never a hard zero-gap). It leaves the speaker's words untouched — false starts, retakes, and stutters are the cut-mistakes agent's job (Agent 2).

This agent is deterministic and transcript-driven, so its output (

*.silence-transcript.json

) feeds cleanly into the next agents and the beat-sync validator.

When to use

"cut the silences", "trim the pauses", "remove dead air", "tighten the pacing"
As the first stage of the master edit workflow, right after transcription.

Prerequisites

A word-level transcript JSON. Either the ElevenLabs Scribe shape (

{ words: [{ text, start, end, type }], audio_duration_secs }

) or a generic

{ words: [{ text, start, end }] }

. Generate one with the workspace transcriber:

bash

node scripts/transcribe-elevenlabs.mjs path/to/raw.mp4    # -> path/to/raw.json

Usage

bash

# 1) Plan only — compute the cut, write EDL + re-timed transcript (no video touched)
node .agents/skills/cut-silences/scripts/cut-silences.mjs <transcript.json> \
  --out-dir video-projects/<slug>/assets

# 2) With a video — also write the ffmpeg command (still does not render yet)
node .agents/skills/cut-silences/scripts/cut-silences.mjs <transcript.json> \
  --video video-projects/<slug>/assets/raw.mp4 --out-dir video-projects/<slug>/assets

# 3) Render the cut video (local ffmpeg, re-encode, A/V kept in sync)
#    add --apply to actually run ffmpeg
node .agents/skills/cut-silences/scripts/cut-silences.mjs <transcript.json> \
  --video video-projects/<slug>/assets/raw.mp4 --apply \
  --output video-projects/<slug>/assets/edited-silenced.mp4

Options

Flag	Default	Meaning
`--video <path>`	—	Source video; enables the ffmpeg command / render
`--out-dir <dir>`	next to transcript	Where outputs are written
`--output <path>`	`<video-stem>.silenced.mp4`	Cut-video path
`--gap <s>`	`0.55`	Minimum pause treated as trimmable silence
`--head-pad <s>`	`0.22`	Silence kept before the first word
`--tail-pad <s>`	`0.34`	Silence kept after the last word
`--apply`	off	Actually run ffmpeg to render the cut

How it decides (the silence rules)

Pauses below
```
--gap
```
(0.55s) are left alone — natural speech rhythm.
For a trimmed pause, a natural breath is kept, scaled by context:
```
0.24s
```
for long pauses (≥2s),
```
0.20s
```
after a sentence ender (
```
. ! ?
```
),
```
0.14s
```
otherwise. The kept breath is biased slightly toward the end of the previous phrase.
Head/tail dead air is trimmed to
```
--head-pad
```
/
```
--tail-pad
```
.
Delete ranges are merged; keep ranges are the complement. The cut is rendered with an ffmpeg
```
trim
```
/
```
atrim
```
+
```
concat
```
filtergraph (written to a
```
*.silence-filter.txt
```
script and passed via
```
-/filter_complex
```
), so video and audio stay in sync.

Outputs (written to

--out-dir

)

File	Purpose
`<stem>.silence-edl.json`	Keep/delete ranges, durations, params — the edit list
`<stem>.silence-transcript.json`	Words re-timed onto the edited timeline (feeds Agent 2 + beats)
`<stem>.silence-decisions.md`	Human-readable summary + largest pauses trimmed
`<stem>.silence-filter.txt`	The ffmpeg filtergraph (only with `--video` )
`<video-stem>.silenced.mp4`	The cut video (only with `--apply` )

The JSON summary printed to stdout includes

removed

,

removedPct

, range counts, and output paths — useful for the master workflow to log and chain.

Tuning notes

Talking-head YouTube default (
```
--gap 0.55
```
) removes roughly 15-20% of a typical raw take as pure silence. Lower
```
--gap
```
for a punchier, faster cut; raise it to preserve more natural breathing room.
If a cut feels too aggressive at sentence boundaries, raise the sentence-break breath, or raise
```
--gap
```
.

Hand-off to the next agent

Pass

<stem>.silence-transcript.json

(and the

silenced.mp4

if rendered) to the cut-mistakes agent. Because timestamps are already on the edited timeline, downstream beat timing and

scripts/validate-beat-sync.mjs

work without further adjustment.

cut-silences

NPX Install

Tags

SKILL.md Content

Cut Silences (Pipeline Agent 1)

When to use

Prerequisites

Usage

Options

How it decides (the silence rules)

Outputs (written to
`--out-dir`
)

Tuning notes

Hand-off to the next agent

cut-silences

NPX Install

Tags

SKILL.md Content

Cut Silences (Pipeline Agent 1)

When to use

Prerequisites

Usage

Options

How it decides (the silence rules)

Outputs (written to --out-dir)

Tuning notes

Hand-off to the next agent

Outputs (written to
`--out-dir`
)