video-editor

# Video Editor (ffmpeg) Video editing operations for cutting, merging, converting, and processing video files. ## Prerequisites Requires `ffmpeg` and `ffprobe` installed: ```bash brew install ffmpeg ``` ## Quick Start ### Cut/Trim Video Extract a segment from a video: ```bash {baseDir}/scripts/cut.sh /path/to/input.mp4 --start 00:00:10 --end 00:00:30 --out /path/to/output.mp4 ``` Or use duration instead of end time: ```bash {baseDir}/scripts/cut.sh /path/to/input.mp4 --start 00:01:00 --duration 30 --out /path/to/output.mp4 ``` ### Merge Videos Concatenate multiple videos (must have same codec/resolution): ```bash {baseDir}/scripts/merge.sh video1.mp4 video2.mp4 video3.mp4 --out merged.mp4 ``` ### Convert Format Convert between video formats: ```bash {baseDir}/scripts/convert.sh input.mov --format mp4 --out output.mp4 ``` ### Extract Audio Extract audio track from video: ```bash {baseDir}/scripts/extract-audio.sh input.mp4 --out audio.mp3 ``` ### Add Subtitles Burn subtitles into video: ```bash {baseDir}/scripts/add-subtitles.sh input.mp4 subtitles.srt --out output.mp4 ``` ### Resize Video Change video resolution: ```bash {baseDir}/scripts/resize.sh input.mp4 --width 1920 --height 1080 --out output.mp4 ``` Or scale proportionally: ```bash {baseDir}/scripts/resize.sh input.mp4 --scale 720 --out output.mp4 ``` ### Adjust Speed Speed up or slow down video: ```bash {baseDir}/scripts/speed.sh input.mp4 --rate 2.0 --out output.mp4 # 2x faster {baseDir}/scripts/speed.sh input.mp4 --rate 0.5 --out output.mp4 # 0.5x slower ``` ### Crop Video Crop to specific region: ```bash {baseDir}/scripts/crop.sh input.mp4 --x 100 --y 100 --width 800 --height 600 --out output.mp4 ``` ## Common Workflows ### Social Media Clip Cut a segment and resize for Instagram/TikTok: ```bash # First cut the segment {baseDir}/scripts/cut.sh input.mp4 --start 00:00:15 --duration 15 --out clip.mp4 # Then resize to vertical format {baseDir}/scripts/resize.sh clip.mp4 --width 1080 --height 1920 --out tiktok.mp4 ``` ### Extract Highlights Cut multiple segments and merge: ```bash {baseDir}/scripts/cut.sh input.mp4 --start 00:00:10 --duration 5 --out highlight1.mp4 {baseDir}/scripts/cut.sh input.mp4 --start 00:01:30 --duration 5 --out highlight2.mp4 {baseDir}/scripts/merge.sh highlight1.mp4 highlight2.mp4 --out highlights.mp4 ``` ### Add Background Music Replace or mix audio: ```bash # Replace audio ffmpeg -i video.mp4 -i music.mp3 -c:v copy -map 0:v:0 -map 1:a:0 -shortest output.mp4 # Mix audio (video audio at 70%, music at 30%) ffmpeg -i video.mp4 -i music.mp3 -filter_complex "[0:a]volume=0.7[a0];[1:a]volume=0.3[a1];[a0][a1]amix=inputs=2:duration=first" -c:v copy -shortest output.mp4 ``` ## Tips - **Quality**: Use `-crf 18` for high quality, `-crf 28` for smaller files (default is 23) - **Presets**: Use `-preset slow` for better compression, `-preset fast` for quicker encoding - **Hardware acceleration**: On Apple Silicon, add `-c:v h264_videotoolbox` for faster encoding - **Copy mode**: Use `-c copy` to avoid re-encoding (much faster, but limited editing) ## Troubleshooting ### Merge fails with "Codec mismatch" Videos must have the same codec, resolution, and frame rate. Re-encode them first: ```bash ffmpeg -i input1.mp4 -c:v libx264 -c:a aac -vf "scale=1920:1080" -r 30 temp1.mp4 ffmpeg -i input2.mp4 -c:v libx264 -c:a aac -vf "scale=1920:1080" -r 30 temp2.mp4 {baseDir}/scripts/merge.sh temp1.mp4 temp2.mp4 --out merged.mp4 ``` ### Subtitles not showing Ensure subtitle file format matches extension (.srt, .ass, .vtt). Check encoding: ```bash file -I subtitles.srt # Should show charset=utf-8 ``` Convert if needed: ```bash iconv -f GBK -t UTF-8 subtitles.srt > subtitles_utf8.srt ```