Audio Handler

Analyze, convert, and process audio files.

Supported Formats

Quick Commands

Metadata (ffprobe)

# Get all metadata
ffprobe -v quiet -print_format json -show_format -show_streams audio.mp3

# Get duration only
ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 audio.mp3

# Get bitrate
ffprobe -v error -show_entries format=bit_rate -of default=noprint_wrappers=1:nokey=1 audio.mp3

# Get sample rate and channels
ffprobe -v error -select_streams a:0 -show_entries stream=sample_rate,channels -of default=noprint_wrappers=1 audio.mp3

# Human-readable info
ffprobe -hide_banner audio.mp3

Convert Formats (ffmpeg)

# Convert to MP3 (good quality)
ffmpeg -i input.wav -codec:a libmp3lame -qscale:a 2 output.mp3

# Convert to MP3 (specific bitrate)
ffmpeg -i input.wav -codec:a libmp3lame -b:a 192k output.mp3

# Convert to WAV (uncompressed)
ffmpeg -i input.mp3 output.wav

# Convert to FLAC (lossless)
ffmpeg -i input.wav output.flac

# Convert to M4A/AAC
ffmpeg -i input.wav -codec:a aac -b:a 256k output.m4a

# Convert to OGG Vorbis
ffmpeg -i input.wav -codec:a libvorbis -qscale:a 5 output.ogg

# Convert to Opus (best for speech)
ffmpeg -i input.wav -codec:a libopus -b:a 64k output.opus

Trim & Clip

# Trim audio (from 30s to 90s)
ffmpeg -i input.mp3 -ss 30 -to 90 -c copy output.mp3

# Trim from start to duration
ffmpeg -i input.mp3 -t 60 -c copy output.mp3  # First 60 seconds

# Trim with re-encode (more accurate)
ffmpeg -i input.mp3 -ss 30 -to 90 output.mp3

Volume & Speed

# Adjust volume (2x louder)
ffmpeg -i input.mp3 -af "volume=2" output.mp3

# Reduce volume (half)
ffmpeg -i input.mp3 -af "volume=0.5" output.mp3

# Normalize audio
ffmpeg -i input.mp3 -af "loudnorm" output.mp3

# Speed up (1.5x)
ffmpeg -i input.mp3 -af "atempo=1.5" output.mp3

# Slow down (0.75x)
ffmpeg -i input.mp3 -af "atempo=0.75" output.mp3

Merge & Concatenate

# Concatenate audio files
ffmpeg -i "concat:part1.mp3|part2.mp3|part3.mp3" -acodec copy output.mp3

# Merge with file list
echo "file 'part1.mp3'" > list.txt
echo "file 'part2.mp3'" >> list.txt
ffmpeg -f concat -safe 0 -i list.txt -c copy output.mp3

# Mix two audio tracks
ffmpeg -i voice.mp3 -i music.mp3 -filter_complex amix=inputs=2:duration=longest output.mp3

Extract Audio from Video

# Extract audio track
ffmpeg -i video.mp4 -vn -acodec copy audio.aac

# Extract and convert
ffmpeg -i video.mp4 -vn -acodec libmp3lame -b:a 192k audio.mp3

Playback (macOS)

# Play audio file
afplay audio.mp3

# Play with volume (0.0 to 1.0)
afplay -v 0.5 audio.mp3

# Play in background
afplay audio.mp3 &

# Stop playback
killall afplay

Text-to-Speech (macOS)

# Speak text
say "Hello, this is a test"

# Save to file
say -o output.aiff "This will be saved as audio"

# List voices
say -v ?

# Use specific voice
say -v "Samantha" "Hello, I am Samantha"

# Convert to MP3
say -o temp.aiff "Text to convert" && ffmpeg -i temp.aiff output.mp3 && rm temp.aiff

Scripts

audio_info.sh

Get comprehensive audio metadata.

~/Dropbox/jarvis/skills/audio-handler/scripts/audio_info.sh <audio_file>

convert_audio.sh

Convert between formats with quality options.

~/Dropbox/jarvis/skills/audio-handler/scripts/convert_audio.sh <input> <output> [quality]

trim_audio.sh

Trim audio with start/end times.

~/Dropbox/jarvis/skills/audio-handler/scripts/trim_audio.sh <input> <output> <start> <end>

normalize_audio.sh

Normalize volume level.

~/Dropbox/jarvis/skills/audio-handler/scripts/normalize_audio.sh <input> <output>

Quality Guide

Notes

• ffmpeg handles almost all audio formats
• -c copy is fast but may be inaccurate for trimming
• Re-encode (-af) for precise cuts but takes longer
• Opus is best for speech at low bitrates
• Use loudnorm filter for consistent volume across files