extract
Extract audio tracks from video files in multiple formats with quality control.
Overview
The extract command extracts audio streams from video files, converting them to standalone audio files in your chosen format. Perfect for creating podcast episodes from video recordings, extracting music from music videos, or creating audio-only versions for mobile consumption.
Key Features:
- Extract from all major video formats (MP4, MKV, AVI, MOV, WebM)
- Output to MP3, AAC, WAV, FLAC, Opus, or OGG
- Quality presets and custom bitrate control
- Sample rate and channel configuration
- Batch processing for multiple videos
Common Use Cases:
- Creating podcast episodes from video recordings
- Extracting music from music videos or concerts
- Creating audio-only versions for offline listening
- Extracting dialogue for transcription
- Archiving audio from video sources
Quality Retention: Extracting audio does not degrade the original audio quality unless you convert to a lower bitrate format. Use lossless formats (FLAC/WAV) to preserve original quality.
Usage
Options
Basic Options
| Option | Alias | Type | Default | Description |
|---|---|---|---|---|
--output | -o | string | Auto | Output file or directory path |
--format | -f | string | mp3 | Output format: mp3, aac, wav, flac, opus, ogg |
--verbose | -v | boolean | false | Show detailed FFmpeg output |
--dry-run | boolean | false | Preview command without executing |
Quality & Encoding
| Option | Alias | Type | Default | Description |
|---|---|---|---|---|
--quality | -q | string | medium | Quality preset: low, medium, high, lossless |
--bitrate | -b | string | 192k | Audio bitrate (e.g., 128k, 192k, 320k) |
--sample-rate | number | Sample rate in Hz (e.g., 44100, 48000) | ||
--channels | number | Number of channels: 1 (mono), 2 (stereo) |
Flag Details
--format - Output Format
Choose the output format based on quality needs and compatibility.
Lossy Formats (Compressed):
MP3 - Universal compatibility
- Best for: General distribution, podcasts, music
- Bitrate range: 96k-320k
- File size: Moderate
AAC/M4A - Better quality per bitrate
- Best for: iOS, iTunes, modern devices
- Bitrate range: 96k-320k
- File size: 20-30% smaller than MP3
Opus - Modern, efficient codec
- Best for: Streaming, web apps, podcasts
- Bitrate range: 32k-256k
- File size: Best compression
OGG Vorbis - Open source
- Best for: Open source projects, web
- Bitrate range: 96k-320k
- File size: Similar to AAC
Lossless Formats:
FLAC - Compressed lossless
- Preserves original audio quality exactly
- File size: 40-50% of WAV
- Best for: Archival, hi-fi playback
WAV - Uncompressed
- Preserves original audio quality exactly
- File size: Largest
- Best for: Professional editing, mastering
--quality - Quality Presets
Convenient presets for common extraction scenarios.
low (96k)
- Podcast speech
- Voice recordings
- Low bandwidth needs
medium (192k) - Default
- Music extraction
- General use
- Good quality/size balance
high (320k)
- High-quality music
- Critical listening
- Near-transparent quality
lossless (FLAC)
- Archival purposes
- Professional work
- Bit-perfect extraction
--bitrate - Audio Bitrate
Control the output quality and file size for lossy formats.
Recommended Bitrates:
| Content Type | Low | Medium | High |
|---|---|---|---|
| Speech/Voice | 64k | 96k | 128k |
| Podcast | 96k | 128k | 192k |
| Music | 128k | 192k | 320k |
| Hi-Fi Music | 256k | 320k | FLAC |
Examples
Extract Audio to MP3
Extract Lossless Audio
Extract and Convert to Opus
Batch Extract from Multiple Videos
Extract with Custom Sample Rate
Common Workflows
Podcast Production
# Extract interview from video recording
mediaproc audio extract interview.mp4 -f mp3 -b 128k
# Create high-quality master
mediaproc audio extract interview.mp4 -f flac -q lossless
Music Archival
# Extract concert audio in lossless format
mediaproc audio extract concert.mkv -f flac
# Create distribution MP3
mediaproc audio extract concert.mkv -f mp3 -b 320k
Mobile Optimization
# Small file size for mobile
mediaproc audio extract video.mp4 -f opus -b 96k
# Mono for voice content
mediaproc audio extract lecture.mp4 -f mp3 -b 96k --channels 1
Video Format Support
Supported Input Formats:
- MP4 - MPEG-4 containers (most common)
- MKV - Matroska containers (high quality)
- AVI - Audio Video Interleave
- MOV - QuickTime format
- WebM - Web video format
- FLV - Flash video (legacy)
- WMV - Windows Media Video
- M4V - iTunes video format
Audio Codec Detection:
The command automatically detects the original audio codec:
- AAC, MP3, Opus, Vorbis, AC3, DTS, PCM, FLAC
Performance Tips
Stream Copy (No Re-encoding):
If the video already contains the desired audio format, you can copy it directly without re-encoding:
# Extract MP3 audio without re-encoding
mediaproc audio extract video.mp4 -f mp3 --codec copy
Note: This only works if the video's audio codec matches your output format.
Preview Before Extracting:
# See what the command will do
mediaproc audio extract video.mp4 -f mp3 --dry-run
Verbose Output:
# Show detailed FFmpeg progress
mediaproc audio extract video.mp4 -f mp3 -v
Quality Considerations
Original Audio Codec:
Video files contain audio in various codecs:
- AAC (most common in MP4)
- AC3/Dolby Digital (DVDs, Blu-rays)
- DTS (high-quality movies)
- Opus (WebM videos)
- Vorbis (older WebM/OGG)
Re-encoding Impact:
- Extracting to a lossy format (MP3, AAC) will re-encode and may reduce quality
- Extracting to lossless (FLAC, WAV) preserves original quality
- Multiple lossy conversions degrade quality (avoid converting lossy → lossy → lossy)
Generational Loss: Each time you convert between lossy formats, quality degrades. Always keep lossless masters and convert from those.
Related Commands
convert- Convert between audio formatsnormalize- Normalize extracted audio levelstrim- Trim extracted audio