video-extract

Video Extract

Process video files with ffmpeg: extract frames, clips, audio, and more.

Prerequisites

Install ffmpeg:

brew install ffmpeg

Verify: ffmpeg -version

Commands

Video Info

ffprobe -v quiet -print_format json -show_format -show_streams input.mp4
# Quick summary:
ffprobe -v error -show_entries format=duration,size,bit_rate \
  -show_entries stream=codec_name,width,height,r_frame_rate input.mp4

Extract Frames

# Single frame at timestamp
ffmpeg -y -i input.mp4 -ss 00:01:30 -vframes 1 frame.jpg

# Frame every N seconds
ffmpeg -y -i input.mp4 -vf fps=1/5 frames/frame_%04d.jpg   # every 5 sec

# All frames (use sparingly on long videos)
ffmpeg -y -i input.mp4 frames/frame_%04d.png

Extract / Trim Clip

# Clip from start time, duration
ffmpeg -y -ss 00:00:30 -i input.mp4 -t 00:00:15 -c copy clip.mp4

# Clip from start to end time
ffmpeg -y -ss 00:01:00 -to 00:02:30 -i input.mp4 -c copy clip.mp4

# Re-encode for clean cut (slower but frame-accurate)
ffmpeg -y -i input.mp4 -ss 00:00:30 -t 00:00:15 clip.mp4

Extract Audio

# Extract as MP3
ffmpeg -y -i input.mp4 -vn -acodec mp3 -q:a 2 audio.mp3

# Extract as AAC (smaller)
ffmpeg -y -i input.mp4 -vn -acodec aac -b:a 192k audio.aac

# Extract as WAV (lossless)
ffmpeg -y -i input.mp4 -vn audio.wav

Format Conversion

# To MP4 (H.264 + AAC, web-compatible)
ffmpeg -y -i input.mov -c:v libx264 -c:a aac -crf 23 output.mp4

# To WebM
ffmpeg -y -i input.mp4 -c:v libvpx-vp9 -c:a libopus output.webm

# To GIF
ffmpeg -y -i input.mp4 -vf "fps=10,scale=640:-1" output.gif

# Compress (reduce size)
ffmpeg -y -i input.mp4 -vcodec libx264 -crf 28 compressed.mp4

Create Thumbnail

# At specific timestamp
ffmpeg -y -i input.mp4 -ss 00:00:05 -vframes 1 -vf scale=640:-1 thumb.jpg

# Best frame (scene detection)
ffmpeg -y -i input.mp4 -vf "thumbnail,scale=640:-1" -frames:v 1 thumb.jpg

Subtitles

# Extract embedded subtitles
ffmpeg -y -i input.mkv -map 0:s:0 subtitles.srt

# Burn subtitles into video
ffmpeg -y -i input.mp4 -vf subtitles=subtitles.srt output_with_subs.mp4

Usage Examples

"Extract a frame every 10 seconds from lecture.mp4"

mkdir -p frames
ffmpeg -y -i lecture.mp4 -vf fps=1/10 frames/frame_%04d.jpg
echo "Frames saved to ./frames/"

"Cut from 2:30 to 5:00 in video.mp4"

ffmpeg -y -ss 00:02:30 -to 00:05:00 -i video.mp4 -c copy clip_2m30s_to_5m.mp4

"Get the audio from interview.mp4 as MP3"

ffmpeg -y -i interview.mp4 -vn -acodec mp3 -q:a 2 interview_audio.mp3

"Convert recording.mov to mp4"

ffmpeg -y -i recording.mov -c:v libx264 -c:a aac -crf 23 recording.mp4

Rules

Check if ffmpeg is installed first: which ffmpeg
If not installed, show brew install ffmpeg and stop
Always use -y flag to avoid interactive prompts
Use -c copy for lossless clip extraction when possible (much faster)
For large files, warn user about processing time before starting long operations
Default output goes in the same directory as input with a descriptive suffix
When extracting many frames, create a subdirectory to avoid clutter
Report output file path and size after completion