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