Audio Extractor

Extracts audio from video files to WAV format for further analysis. Converts to mono 16kHz PCM format optimized for speech/energy analysis.

Use Cases

• Extracting audio for speech analysis
• Preparing audio for energy calculation
• Converting video audio to standard format

Usage

python3 /root/.claude/skills/audio-extractor/scripts/extract_audio.py \
    --video /path/to/video.mp4 \
    --output /path/to/audio.wav

Parameters

• --video: Path to input video file
• --output: Path to output WAV file
• --sample-rate: Audio sample rate in Hz (default: 16000)
• --duration: Optional duration limit in seconds (default: full video)

Output Format

• Format: WAV (PCM 16-bit signed)
• Channels: Mono
• Sample rate: 16000 Hz (default)

Dependencies

• ffmpeg

Example

# Extract first 10 minutes of audio
python3 /root/.claude/skills/audio-extractor/scripts/extract_audio.py \
    --video lecture.mp4 \
    --duration 600 \
    --output audio.wav

Notes

• Output is always mono for consistent analysis
• 16kHz sample rate is sufficient for speech analysis and reduces file size
• Supports any video format that ffmpeg can read

Skill Companion Files

Additional files collected from the skill directory layout.

scripts/extract_audio.py

#!/usr/bin/env python3
"""
Audio extractor - extracts audio from video to WAV format.
"""

import argparse
import os
import subprocess


def extract_audio(video_path, output_path, sample_rate=16000, duration=None):
    """Extract audio from video to WAV format."""
    cmd = [
        "ffmpeg",
        "-i",
        video_path,
        "-vn",  # No video
        "-acodec",
        "pcm_s16le",  # 16-bit PCM
        "-ar",
        str(sample_rate),  # Sample rate
        "-ac",
        "1",  # Mono
    ]

    if duration:
        cmd.extend(["-t", str(duration)])

    cmd.extend([output_path, "-y"])

    subprocess.run(cmd, check=True, capture_output=True)

    return output_path


def main():
    parser = argparse.ArgumentParser(description="Extract audio from video")
    parser.add_argument("--video", required=True, help="Path to input video")
    parser.add_argument("--output", required=True, help="Path to output WAV file")
    parser.add_argument("--sample-rate", type=int, default=16000, help="Sample rate (default: 16000)")
    parser.add_argument("--duration", type=int, default=None, help="Duration limit in seconds")

    args = parser.parse_args()

    print(f"Extracting audio from: {args.video}")
    print(f"Sample rate: {args.sample_rate} Hz")
    if args.duration:
        print(f"Duration limit: {args.duration}s")

    extract_audio(args.video, args.output, args.sample_rate, args.duration)

    # Get output file size
    size_mb = os.path.getsize(args.output) / (1024 * 1024)
    print(f"\nAudio extracted to: {args.output}")
    print(f"File size: {size_mb:.2f} MB")


if __name__ == "__main__":
    main()