trim

Cut audio segments with precise timing control and optional fade effects.

Overview

The trim command extracts specific time ranges from audio files with frame-accurate precision. Whether you're cutting interview highlights, removing unwanted segments, or creating short clips for social media, this command provides precise control with professional fade options.

Key Features:

• Time-based trimming (HH:MM:SS format or seconds)
• Duration-based extraction
• Optional fade-in and fade-out effects
• Fast mode (stream copy without re-encoding)
• Frame-accurate cutting
• Batch processing for multiple files

Common Use Cases:

• Creating podcast highlights or clips
• Removing intro/outro from recordings
• Extracting music choruses or verses
• Creating social media audio clips
• Removing unwanted sections (coughs, background noise)
• Batch trimming multiple recordings to same length

Usage

Options

Basic Options

Time Selection

Effects & Output

Flag Details

--start - Start Time

Specify where to begin the trim. Accepts multiple time formats.

Time Formats:

Seconds (Numeric)

• Examples: 30, 90, 125.5
• Use for: Quick cuts, simple ranges

HH:MM:SS (Time format)

• Examples: 00:01:30, 00:02:45.500
• Use for: Precise timing, longer content

MM:SS (Shortened format)

• Examples: 01:30, 02:45
• Use for: Content under 1 hour

Examples:

# Start at 30 seconds
--start 30

# Start at 1 minute 30 seconds
--start 00:01:30
--start 90

# Start at 2 hours 15 minutes
--start 02:15:00

--end - End Time

Specify where to stop the trim (inclusive). Uses same time formats as --start.

Usage:

You must specify either --end OR --duration, but not both:

• Use --end when you know the exact end timestamp
• Use --duration when you know how long the clip should be

Examples:

# Trim from 30s to 90s (60 seconds total)
--start 30 --end 90

# Trim from 1:00 to 2:30
--start 00:01:00 --end 00:02:30

# Extract first 30 seconds
--start 0 --end 30

--duration - Duration

Specify the length of the extracted segment. Uses same time formats.

Usage:

Alternative to --end. The trim will start at --start and continue for this duration.

Examples:

# Extract 60 seconds starting from 30s
--start 30 --duration 60

# Extract 2 minutes starting from the beginning
--duration 120
--duration 00:02:00

# Extract 30 seconds starting from 1 minute
--start 60 --duration 30

Tip: Duration is often more intuitive than calculating end times.

--fade-in - Fade-In Effect

Apply a gradual volume increase at the start of the trimmed audio.

Duration Range: 0.1 to 10 seconds

Common Values:

0.5-1 second - Quick fade

• Music transitions
• Hiding cut marks
• Smooth starts

2-3 seconds - Standard fade

• Radio-style intros
• Podcast episode starts
• Professional feel

4-5 seconds - Slow fade

• Cinematic effect
• Ambient tracks
• Gradual introductions

Examples:

# Quick 1-second fade-in
--fade-in 1

# Professional 2.5-second fade
--fade-in 2.5

# Cinematic 5-second fade
--fade-in 5

--fade-out - Fade-Out Effect

Apply a gradual volume decrease at the end of the trimmed audio.

Duration Range: 0.1 to 10 seconds

Common Values:

Same as fade-in. Typically matched (e.g., 2s fade-in + 2s fade-out).

Examples:

# Fade in and out
--fade-in 2 --fade-out 2

# Quick ending
--fade-out 1

# Slow cinematic ending
--fade-out 5

Audio Fade Curves:

Fades use a linear volume curve by default, which sounds natural for most content.

--fast - Fast Mode

Enable stream copy mode for instant trimming without re-encoding.

How It Works:

• Copies audio data directly without decoding/re-encoding
• Nearly instant processing
• No quality loss
• Only cuts at keyframe boundaries (may be slightly imprecise)

When to Use:

• Large files where re-encoding would take too long
• Format and codec don't need to change
• Precision within ~1 second is acceptable
• Quick previews or rough cuts

When NOT to Use:

• Need frame-accurate cuts
• Applying fade effects (requires re-encoding)
• Changing format or codec
• Professional/broadcast work requiring exact timing

Examples:

# Fast trim (stream copy)
mediaproc audio trim podcast.mp3 --start 60 --duration 300 --fast

# Accurate trim (re-encode)
mediaproc audio trim podcast.mp3 --start 60 --duration 300

Examples

Extract 60 Seconds from Middle

Trim with Fade Effects

Fast Trim for Quick Preview

Batch Trim Multiple Files

Remove Intro and Outro

Extract Chorus with Fades

Common Workflows

Podcast Editing

# Remove intro music (starts at 30s)
mediaproc audio trim episode.mp3 --start 30

# Extract highlight clip
mediaproc audio trim episode.mp3 --start 15:30 --duration 120 --fade-in 1 --fade-out 2

# Create teaser (first 60s with fade-out)
mediaproc audio trim episode.mp3 --duration 60 --fade-out 3

Music Editing

# Extract chorus
mediaproc audio trim song.flac --start 90 --duration 45

# Create radio edit (trim long intro/outro)
mediaproc audio trim album-version.flac --start 15 --end -20

# Make loop with crossfade
mediaproc audio trim beat.wav --start 8 --duration 16 --fade-in 0.5 --fade-out 0.5

Social Media Clips

# Create 15-second TikTok clip
mediaproc audio trim song.mp3 --start 60 --duration 15 --format mp3

# Instagram Story audio (15s with fades)
mediaproc audio trim track.mp3 -s 75 -d 15 --fade-in 0.5 --fade-out 1

# Twitter audio clip (2:20 max)
mediaproc audio trim audio.mp3 --duration 140 --format mp3

Interview Editing

# Remove preparation time at start
mediaproc audio trim interview.wav --start 120

# Extract specific answer
mediaproc audio trim interview.wav --start 15:30 --end 18:45

# Quick rough cut for review
mediaproc audio trim interview.wav -s 300 -d 600 --fast

Time Calculation Tips

Converting to Seconds:

• 1 minute = 60 seconds
• 10 minutes = 600 seconds
• 1 hour = 3600 seconds

Useful Conversions:

# 1:30 (1 min 30 sec)
--start 90

# 5:45 (5 min 45 sec)
--start 345

# 15:00 (15 minutes)
--start 900

Duration Calculations:

# Extract from 1:00 to 3:30 (2min 30sec)
--start 60 --end 210
--start 60 --duration 150

# Extract from 10:00 to 15:00 (5 minutes)
--start 600 --end 900
--start 600 --duration 300

Quality Considerations

Re-encoding:

When not using --fast, audio is re-encoded:

• Lossy formats (MP3, AAC): Slight quality loss
• Lossless formats (FLAC, WAV): No quality loss

Multiple Trims:

Avoid trimming already-trimmed lossy files repeatedly:

• Each trim re-encodes (lossy → lossy)
• Quality degrades with each generation
• Always trim from original source when possible

Format Preservation:

By default, output format matches input. Use --format to convert while trimming.

Performance Tips

Fast Mode for Large Files:

# Instant trim for previews
mediaproc audio trim large-file.mp3 --start 300 --duration 60 --fast

Preview Before Processing:

# See the command before running
mediaproc audio trim audio.mp3 --start 60 --duration 120 --dry-run

Verbose Output:

# Monitor progress for long files
mediaproc audio trim audio.mp3 --start 300 -d 600 -v

Batch Processing:

# Trim all files to same length
for file in *.mp3; do
  mediaproc audio trim "$file" --start 0 --duration 180
done

# Or use globbing
mediaproc audio trim *.mp3 -s 0 -d 180 -o trimmed/

Precision Notes

Frame Accuracy:

• Audio is sampled at specific rates (44.1kHz, 48kHz, etc.)
• Each sample is 1/44100 or 1/48000 of a second
• Trimming is accurate to the sample level when re-encoding
• Fast mode (stream copy) is accurate to codec frame boundaries (~26ms for MP3)

Fade Timing:

Fade effects are applied AFTER trimming:

• Fade-in starts at the trim start time
• Fade-out ends at the trim end time
• Fades do not extend beyond the trimmed boundaries

Negative Times:

Some players support negative end times (trim from end):

# Remove last 30 seconds
--start 0 --end -30

Note: This feature depends on FFmpeg version and may not work in all cases.

Related Commands

• convert - Convert trimmed audio to other formats
• normalize - Normalize after trimming
• merge - Combine multiple trimmed clips

Learn More

• FFmpeg Trim Filter
• Audio Fade Effects
• Stream Copy Explained