Actions

Actions define what auto-editor does to different parts of your media. By default, silent sections are cut out and loud sections are kept at normal speed. Actions give you fine-grained control over this behavior.

Basic Syntax

Actions are specified using the --when-silent and --when-normal options:

# Cut silent sections (default behavior)
auto-editor video.mp4 --when-silent cut

# Keep normal sections unchanged (default behavior)
auto-editor video.mp4 --when-normal nil

Available Actions

nil

Syntax: nil

Do nothing. Keep the section unchanged at normal speed with normal pitch.

# Keep everything, even silent sections
auto-editor video.mp4 --when-silent nil

cut

Syntax: cut

Remove the section completely from the output.

# Remove silent sections (default behavior)
auto-editor video.mp4 --when-silent cut

# Remove loud sections (inverted editing)
auto-editor video.mp4 --when-normal cut

speed

Syntax: speed:<value>

Change the playback speed while preserving pitch using time-stretching.

Value range: 0.0 to 99999.0
Typical range: 0.5 to 3.0

# Speed up silent sections to 8x (preserving pitch)
auto-editor video.mp4 --when-silent speed:8

# Slow down normal sections to half speed
auto-editor video.mp4 --when-normal speed:0.5

How it works: Uses FFmpeg's atempo filter to change speed without affecting pitch. This is like a DJ's time-stretching feature.

varispeed

Syntax: varispeed:<value>

Change the playback speed by varying pitch, like analog tape or vinyl.

Value range: 0.2 to 100.0
Typical range: 0.5 to 2.0

# Speed up silent sections with pitch variation
auto-editor video.mp4 --when-silent varispeed:2

# Create slow-motion effect with lower pitch
auto-editor video.mp4 --when-normal varispeed:0.5

How it works: Uses FFmpeg's asetrate filter to change sample rate, which changes both speed and pitch together. This is the classic tape speed effect.

volume

Syntax: volume:<value>

Adjust the audio volume level.

Value range: Any positive float
1.0 = normal volume
0.5 = half volume (-6dB)
2.0 = double volume (+6dB)

# Reduce silent section volume to 20%
auto-editor video.mp4 --when-silent volume:0.2

# Boost loud sections
auto-editor video.mp4 --when-normal volume:1.5

Multiple Actions (Chaining)

You can combine multiple actions using commas. Actions are applied in the order specified and their effects multiply together.

# Speed up AND reduce volume
auto-editor video.mp4 --when-silent speed:3,volume:0.5

# Combine speed and varispeed for complex effects
# Effective speed: 1.25 × 1.25 = 1.5625x
auto-editor video.mp4 --when-normal varispeed:1.25,speed:1.25

# Triple action: speed, varispeed, and volume
auto-editor video.mp4 --when-silent speed:2,varispeed:1.5,volume:0.8

How Speed Multiplies

When you combine speed and varispeed, their effects multiply:

# These combinations give you fine control:
varispeed:1.25,speed:1.25  # = 1.5625x total speed
varispeed:2,speed:0.5      # = 1x speed (varispeed pitch, normal speed)
speed:2,speed:1.5          # = 3x total speed

Common Use Cases

Fast-Forward Through Silence

auto-editor video.mp4 --when-silent speed:8

Subtle Speed Variations

# Slightly slow down normal sections for emphasis
auto-editor video.mp4 --when-normal speed:0.9

Duck Audio During Silence

# Keep silent sections but reduce volume
auto-editor video.mp4 --when-silent volume:0.3

Creative Effects

# Nightcore effect: speed up and pitch up
auto-editor video.mp4 --when-normal varispeed:1.25

# Slow-mo with deep voice
auto-editor video.mp4 --when-normal varispeed:0.75

# Fast silent sections with reduced volume
auto-editor video.mp4 --when-silent speed:6,volume:0.4

Podcast Editing

# Cut silence, slightly speed up speech
auto-editor podcast.mp3 --when-silent cut --when-normal speed:1.15

Music Editing

# Keep everything but boost quiet parts
auto-editor song.mp3 --when-silent volume:1.8 --when-normal volume:1.0

Deprecated Options

The following options are deprecated but still supported:

# Old way (deprecated)
auto-editor video.mp4 --silent-speed 8 --video-speed 1

# New way (preferred)
auto-editor video.mp4 --when-silent speed:8 --when-normal speed:1

Technical Details

Audio Processing

speed: Uses atempo filter, supports values 0.5-100.0 per stage
varispeed: Uses asetrate + aresample, range 0.2-100.0
volume: Uses volume filter, any positive value

Video Processing

Both speed and varispeed affect video frame selection
Effects multiply together for combined speed calculations
Video is resampled to match the effective playback speed

Filter Chain Order

When using multiple actions, they're applied in this order:

speed (time-stretching)
varispeed (sample rate change)
volume (gain adjustment)

This order ensures optimal audio quality.

Examples by Category

Speed Variations

# Subtle speedup
auto-editor video.mp4 --when-normal speed:1.1

# Aggressive silence removal
auto-editor video.mp4 --when-silent speed:99999
# (speed:99999 is equivalent to cut)

# Complex speed layering
auto-editor video.mp4 --when-normal speed:1.2,varispeed:1.1

Volume Control

# Normalize loud/quiet sections
auto-editor video.mp4 --when-silent volume:2 --when-normal volume:0.8

# Ducking effect
auto-editor video.mp4 --when-silent volume:0.1

Creative Combinations

# Chipmunk effect on silence
auto-editor video.mp4 --when-silent varispeed:2,volume:1.2

# Deep voice on normal sections
auto-editor video.mp4 --when-normal varispeed:0.7

# Fast and quiet silence
auto-editor video.mp4 --when-silent speed:10,volume:0.2